4201 4205.output

* GB784608 (A)

Description: GB784608 (A) ? 1957-10-09

Manufacture of oximes of cycloaliphatic ketones

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The EPO does not accept any responsibility for the accuracy of data and information originating from other authorities than the EPO; in particular, the EPO does not guarantee that they are complete, up-to-date or fit for specific purposes.

COMPLETE SPECIFICATION Manufacture of Oximes of Cycloaliphatic Ketones We, FARBWERKE HOECHST AKTIENGESELL- SCHAFT vormals Meister Lucius & Bruning, a body corporate recognised under German law, of Frankfurt (M)-Hochst, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement :- Various processes are already known for reducing secondary cycloaliphatic nitro-hydrocarbons, for example, with stannous chloride or with hydroxylamine or also with hydrogen and a catalyst, to obtain the oximes of the cycloaliphatic ketones. The present invention is based on the obser- vation that the salts of thiosulphuric add or the salts of polythionic acids can be used in aqueous solution as reducing agents for the manufacture of oximes from the water-soluble salts of secondary nitro-compounds of the cycloaliphatic series, the nitro-compound and salt of thiosulphuric acid and ! or polythionic acid being used in the proportion of 1 mol of nitroWcompoundt to 1 to 1-mols of salt of thiosulphuric acid and/or salt of polythionic acid. As aqueous salt solutions of secondary nitrocycloaliphatic hydrocarbons, thiosulphuric acid polythion acids there are chiefly

used the alkali metal and ammonium salt solutions. The sodium and potassium salts of the said compounds are particularly suitable for the purpose in question. Spedification N 738,888 describes and claims a process for the production of oximes wherein there are introduced aqueous solutions of about eauivalent amounts of secondary aliphatic or cycloaliphatic aci-nitro compound or their salts and of thiosulphates simultaneously into excess aqueous acid. In the examples of said specificaton, two mols of reducing agent are used per mol of nitrocompound, as opposed to the use of 1 to 11, mols of reducing agent ner mol of nitro-comc pound according to the present invention. No reaction occurs in an alkaline solution but only in a neutral to acid solution, preferably adjusted by the rapid addition of the acid required to effect this condition of nonalkalinity. Since during the addition of the acid to an aqueous solution of a salt of a secondary nitro-cycloaliphatic hydrocarbon in the presence of a water-soluble salt of thiosulphuric acid andi/or a water-soluble salt of a polythionic acid the reaction can take place in various directions, exactly defined reaction conditions must be observe. Besides the preferred rapid addition of the acid, it is of pri- mary importance to operate at a temperature below 50 C., preferably at a temperature between-10 C. and +10 C. The reduction takes place when, for example, to a solution containing both a nitro-hydrocarbon salt and an alkali thiosulphate, a quantity of acid is rapidly added until the solution shows a neutral to acid reaction, the pH value not exceeding 7. This occurs as soon as the alkali present, which is derived from solution of the nitro-cycloaliphatic hydrocarbon, is neutralised and in addition thereto about half of the first stage of dissociation of the salt of the thiosulphuric acid or of the salts of the polythionic acid. The reaction takes place rapidly and is complete after stirring has been continued for 1-3 hours. A mixture of thiosulphate salts and polythionic acid salts may also be used as reducing component. It is likewise possible tu use a mixture of the various polythionic acid salts. If the polythionic acid salts are used alone for the reduction, all the members of that group are suitable, such as the di-, tri-, tetra-, penta-and hexathionic acid salt. The addition of an acid must be carried out with due regard to the following principle. The acid causes the liberation of the thio acid in question from the salt of the particular reducing thio acid salt.-By adding an acid rapidly, as mentioned above, the thio, acid set free can exert its reducing action immediately after its formation, the danger of spontaneous decomposition with formation of elementary sulphur being

thus avoided. If this principle is observed, those skilled in the art will be able without difflculty to fix the length oR the period in each individual case during which addiiica- tion must take place. It should be noted, in order to avoid loss, that in a medium containing the above-named sulphur compound, the oximes of the cyclo aliphatic ketones are of better solubility in pure water. From the aqueous reaction solu tions from which the oxime has been separated a large proportion of the available sulphur can be recovered. The process can be considerably improved by adding, before or after the introduction of the acid, a small proportion of hydroxylamine or a salt thereof, such as a hydroxylamine sulphonate, or of a mixture of compound yielding hydroxylamine under the reaction conditions. For example, a mixture of sodium nitrite and sodium bisulphite in aqueous solution may be used in the reduction of the salts of nitrocycloaliphatic hydrocarbons, because the hydroxylamine sulphonates are formed therefrom according to the so-called Raschig process. Via to 1/, mol of hydroxylamine is sufficient per 1 mol of nitro-cycloaliphatic hydrocarbon. All the cycloaliphatic secondary nitro-compounds which contain up to a maximum of 20 carbon atoms may be used in the present process. As reducing agents there may be used all the water-soluble salts of thiosulphuric acid or of the polythionic acids. The neutralisation or acidification can be carried out by means of strong inorganic acids, for example hydrocloric and sulphuric acids. The oximes which are obtained by the process of the present invention can, in general, be used directly for the great variety of purposes for which the oximes are useful. The yields obtained by the present process may rise to about 92 per cent. In the case of tri-, tetra and pentathionic acids, which are relatively stable, it is possible to mix at a low temperature the polythionic acid salt and the acid to be added to the reaction mixture ; the salt solution of nitro-cycloaliphatic hydrocarbon is then caused to run in. Here again the object is to ensure that the polythionic acid set free does not undergo a decomposition with separation of sulphur, before it can exert its reducing action. The following examples illustrate the invention, the parts being by weight unless otherwise stated and the relation between part by weight and part by volume being the same as that of the kilogram to the litre :-

EXAMPLE 1. A solution of 300 parts of crystalline sodium thiosulphate (Na, 520. 1. 5HO) in 250 parts by volume of water is added at 0 C. to a solution of 130 parts of nitrocyclohexane in 605 parts by volume of 2. 5N-sodium hydroxide solution. The mixture is stirred for 1 hour at 0 C. alld 600 parts by volume of 4N-hydrochloric acid (cooled tO-105 C) are then rapidly added. The solution assumes an intensive blue coloration which only slowly disappears. After stirring has been continued for 3 hours, the hydrogen ion concentration is adjusted to a pH-value of 6 to 7 and the cxime is separated and extracted with ether. After the evaporation of the ether, the solution is distilled under reduced pressure. The total yield amounts to 70 parts of cyclohexanone- oxime, corresponding to 65 per cent. EXAMPLE 2. A solution of 300 parts of crystalline scdium thiosulphate (Na25203. 5H20) in 250 parts by volume of water is added at 0'C. to a solution of 130 parts of nitrocyclohexane in 605 parts by volume of 2. 5N-sodium hydroxide solution. The mixture is stirred for 1 hour at 0 C. and 700 parts by volume of 4N-hydrochloric acid (cooled to-10 C.) are then rapidly added. The solution assumes an intensive blue coloration. After 2 to 5 minutes a saturated aqueous solution of 2 parts of hydroxylamine hydrochloride is added and stirring is continued for 1 hour. The hydrogen ion concentration is adjusted to a pH-value of 6 to 7, the solution is filtered with suction and the filtrate is extracted with ether. The ether is evaporated and the residue is distilled under reduced pressure. The total yield amounts to 100 parts of cyclohexanone-oxime corresponding to 92 per cent. EXAMPLE 3. 500 parts by volume of 4N-HC1 (cooled to 18 C.) are carefully added to a solution cooled to 0'C. of 250 parts of sodium trithionate (Na2S30G) in 300 parts by volume of water. A solution cooled to 0 of 130 parts of nitro-cyclohexane in 605 parts by volume of 2. 5N-sodium hydroxide solution is then caused to run in. The solution assumes a blue-green coloration which only slowly disappears. After 2 hours the hydrogen ion concentration is adjusted to a pu-value of 6 to 7 and the solution is filtered with suction. The nitrate is extracted with ether. The ether is evaporated and the residue is distilled under reduced pressure. The yield amounts to 30 parts of pure cyclohexanone-oxime corresponding to 27. 5 per cent.

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* GB784609 (A)

Description: GB784609 (A) ? 1957-10-09

Improvements in or relating to processes for reducing acidity of nitric acidsolutions containing metal salts

Description of GB784609 (A)

PATENT SPECIFICATION Inventor: THOMAS VICTOR HEALY Date of filing Complete Specification Nov 16, 1954. Application Date Nov 17, 1953. 784,609 No 31918/53. o Complete Specification Published Oct 9, 1957. Index at Acceptance:-Classes 1 ( 2), A 2; 1 ( 3), A 1 (D 28: GX); and 32, B 5 E. International Classification: -B Old C 01 b, g. COMPLETE SPECIFICATION Improvements in or relating to Processes for Reducing Acidity of Nitric Acid Solutions, containing Metal Salts We, UNITED KINGDOM ATOMIC ENERGY AUTHORITY, of London, a British Authority do hereby declare the invention, for which we pray that a patent may be granted to us, and the nithod by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to the reduction of the acidity of aqueous solutions containing nitric acid. In the processing of aqueous nitric acid solutions of chemical substances particularly fission products, wherein reduction of the bulk of the solutions by evaporation is carried out, the concentration of the nitric acid that will result may be undesirably high It is known (Ber vol 32, 1392 ( 1899)) that fornmaldehyde decomposes nitric acid with the formation of gaseous products and water The addition of formaldehyde to such nitric acid solution during reduction of the bulk

by evaporation would therefore be suitable for reducing the acid concentration. The present invention is based on the observations that with solutions containing nitric acid of concentration not exceeding 8 N the following reaction takes place with formaldehyde:3 CH 20 + 4 HN Oa,-> 4 NO+ 3 CO 2 + 5 HO and that nitric oxide is capable of decomposing nitric acid of concentration above 8 N to produce nitrogen dioxide and water According to the invention a heated nitric acid solution not exceeding 8 N and containing metal salts is treated with formaldehyde to decompose nitric acid with the formation of nitric oxide and the nitric oxide is passed into contact with further nitric acid solution of acidity above 8 N and containing metal salts, whereby to decompose nitric acid in the further nitric acid solution of metal salts and reduce the acidity thereof to a value below 8 N. In a preferred form of the present invention the nitric oxide is produced continuously and is continuously contacted with the aqueous solution of acidity above 8 N to reduce its acidity to a value not exceeding 8 N, and this solution is then contacted with formaldehyde so as to produce nitric oxide In a further 50 preferred form the nitric oxide is contacted in countercurrent flow with the aqueous solution having acidity above SN In a particularly preferred form of the present invention water is evaporated from the aqueous solu 55 tion having acidity not exceeding 8 N. By using the process of the invention the formaldehyde may be employed more economicallv to reduce the concentration of nitric acid in aqueous solutions to low values 60 The formaldehyde may be used in gaseous form or as an aqueous solution, conveniently the commercially available 35 to 40 per cent solution, or as paraformaldehyde. For carrying out the invention in a continu 65 ous manner there may be employed a vessel serving as a boiler and provided with an inlet for formaldehyde, an outlet for removing solution of Iow acid content and a gas and vapour outlet leading to a vertical packed column to 70 the top of which solution to be treated may be fed. Initially the nitric acid solution less than SN in nitric acid is introduced into the boiler and the temperature raised to the boiling 75 point Formaldehyde, preferably in the form of a 35 to 40 per cent aqueous solution, is introduced to bring about the decomposition of nitric acid to nitric oxide A flow of the nitric acid solution, containing nitric 80 acid above 8 N, into the top of the packed column is started, the rate of flow being maintained in proportion to the nitric oxide given off from the solution in the boiler The solution fed to the top of the column is preferably 85 obtained by the evaporation of water from an aqueous solution of metal salts in nitric acid having acidity not exceeding 8 N.

The concentration of nitric acid in the solution descending the column will decrease by 90 reaction with the nitric oxide evolved in the boiler and will undergo further decrease in the boiler Solutions having low nitric acid content may be withdrawn from the vessel continuously and subjected to concentration by evaporation. In this way a reduction of the nitric acid concentration from 15 N to 0 25 N can be effected. The following is a preferred way of carrying the invention into effect, as applied by way of example to an aqueous solution which has resulted from dissolving neutron-irradiated uranium in nitric acid and separating the majority of the uranium and plutonium, the solution containing fission products nitric acid and low concentrations of added electrolytes, reference being made to the accompanying drawing which shows in vertical cross section a form of apparatus which may be employed. The boiler 1, which may be of stainless steel or other corrosion resistant substance, is arranged on an electrical heater unit 2 and is provided with pipes 8 and 10 The neck of boiler 1 is attached to a vertical column 3 which is packed with ceramic packing 4 or other packing resistant to nitric acid, the column having a sprayer 7 attached to a pipe The upper end of the column is connected to a pipe 6 through which gases generated in the apparatus may be discharged At the lower end of the column a grid 11 supports the packing 4. The aqueous solution, 8 N in nitric acid and containing fission products is introduced into the apparatus by way of pipe 6 and when an appropriate amount of the solution 9 has collected in the boiler 1, the electrical heater 2 is energized to bring the solution to the boiling point A 40 per cent aqueous solution of formaldehyde is run into the boiler by way of the pipe 8 Further aqueous solution about 15 N in nitric acid and containing fission products is passed into the apparatus by way of pipe 5 and the sprayer 7 Nitric oxide evolved in the boiler 1 passing up the column 3 in countercurrent flow to the aqueous solution reacts with the nitric acid The solution entering the boiler 1 from the column will undergo a turther reduction in nitric acid content in boiler 1 and solution containing 0.25 N nitric acid is withdrawn by way of the pipe 10 The latter solution is subjected to concentration by evaporation to raise the normality in nitric acid to 15 N, and the concentrated solution again introduced into the apparatus for further reduction of the nitric acid content In this manner the concentration of the dissolved metal salts was increased fifty fold while the nitric acid was reduced to 0 25 N.

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* GB784610 (A)

Description: GB784610 (A) ? 1957-10-09

Process for preparing -ss-ketoacetals




COMPLETE SPECIFICATION Process for preparing ~-Ketoacetals We, EASTMAN RODAS COMPANY, a company organise under the laws of the State of New Jersey, United States of America, of 343, State Streot, Rochester, New York, United States of America (Assignees of DONALD MACARTHUR BURNESS, GEORGE LELAND FLETCHER and JAMES SAMUEL HULL), do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statemem :- This invention relates to the preparation of chemical compound in particular to the preparation of ?-ketoaldehyde acetals. Several methods have been proposed for preparing ketoacetals. Nelles (United States Patent 2, 091, 373) described a preparation involving an alkyl 2-chloro-vinyl ketone but this synthesis is difficult te handle on a

commercial scale because of the nature of the intermediates. Kaushall (J. Indian Chem. Soc., 20, 53) described reacting sodium hydroxymethylene acetone with ethyl alcohol in the presence of ethyl bromide to form the jS-ketovinyl ether. This method actually forms a mixture of the ~-ketovinyl ether and the ~-ketoacetal as shown by subsequent work. Dyer et al (J.A.C.S, 56, 222 (1934)) showed that sodium ethyl formyl acetate formed an acetal with ethyl alcohol in the presence of hydrogen chloride. Sugasawa (Japanese Patent 177, 821) and, later, Richmond (United States Patent 2, 570, 713) reacted sodium hydroxymethylene acetone with ethyl alcohol in the presence of hydrogen chloride to form (3-kembutyraldehyde diethyl acetal but the yield was low (45. 7 and 20%) and the product contained a sizable quantity (10% and 24%) of triacetyl benzene. Richmond also propose the use of other alcools such as methyl alcohol to form the corresponding acetal. We have found that the Richmond process, like that of Kaushall, gives a large amount of ~-ketovinyl ether in the product which is difficult to separate and which greatly lessens the yield of the desired R-lcetoacetal. In the Itichmond process the sodium hydroxymethylene ketone, alcohol and hydrogen chloride are brought together or commingled or, preferably, the hydrogen chloride in solution in the alcohol is admixed with the sodium hydroxymethylene ketone by which procedure an excess of the sodium compound is present during the first part of the mixing period. In the Richmond process also sodium bicarbonate is used to neutralize excess acid after reaction, resulting in the formation of water in the reacted mixture. According to the present invention there is provided a method of making the dimethyl acetal of an aliphatic-ketoaldehyde as herein defined which comprises making a substantially anhydrous mixture (1), comprising an alkali metal enolate of the ; S-keto-aldehyde, anhydrous methyl alcohol and anhydrous hydrogen chloride, allowing the mixture (1) to react, neutralising the reacted mixture (2) and separating the dimethyl acetal of the jS-ketoaldehyde from the resulting mixture (3), said method being characterised in that said enolate is added with mixing to a solution of such an amount of said hydrogen chloride in said methyl alcohol that the pH of the mixture (1) is maintained below 1 throughout the mixing, the mixture (1) is allowed to react at said pH at a temperature not above 25 C., the pH ot the reacted mixture (2) is raised to from 6 to 7 by the addition of an alkali metal alkoxide and the resulting mixture is maintained at said latter pu while the dimethyl acetal of the ~-ketoaldehyde is separated therefrom. In a preferred embodiment of the present invention the mixture (1)

also contains methyl formate. The pH values referred to and as used hereinafter represent the apparent pH values for the non-aqueous system as measured on a Beckmann tz meter. Aliphatic ss-ketoaldehydss, of which the dimethyl acetals are prepared according to the present invention, are represented by the formula R. CO. CEI (RX wherein R is an alkyl, vinyl or aralkyl group and Rl is H or an alkyl group. The alkali metal enolates of these aliphatic j6-ketoaldehydes are repre sented by the formula R. CO. CR') =CH. OM wherein R and RI have the meanings g, iven above. The reaction which is believed to take place in the formation of the enolate des crib d below is indicated as follows :- R. CO. CH+H. CO. OR+MOR"'-R. CO. C (R') =CHOM+R"OH+R"'OH @@@@@@@@@@@@@@@@@@ meaning given above, R 11 is an alkyl group, R 111 is an alkyl group and M is an alkali metal atom. In practising the present invention, the desirea alkali metal enolate of the Jb etoaide- hyde can be prepared in any known manner. Preferably, however, the enolate is prepared by reacting an alkali metal, such as sodium or potassium, or an alkali metal alkoxide, such as sodium methoxide, sodium ethoxide, sodium isopropoxide or the corresponding potassium or other alkali metal alkoxide, with an alkyl formate, such as metayl or ethyl formate, and a ketone, such as acetone, methyl etnyi ketone, methyl vinyl ketone or the like, to form the alkali metal enolate. In the preferred form of the present mvention, however, the mixture (1) contains also methyl formate. In practising the preferred form of the present invention, the desired alkali metal enolate is preferably prepared by reacting an alkali metal or alkali metal aloo- holate, and a ketone with excess methyl formate to form a slurry of alkali metal tormyl ketone in the methyl formate. Although in the preferred form ot the present invention the alkali metal formyl Hetone is prepared by reacting a ketone, and an alkali metal or alkali metal alcoholate in excess methyl formate (which may if desired contain small amounts of other alkyl formates such as ethyl formate), to form a slurry of the alkali metal formyl ketone in the methyl formate for direct addition to the methyl alcohol and hydrogen chloride, the alkali metal formyl ketone can be prepared in any desired manner and can be then admixed with methyl formate prior to addition to the acetalizing reaction mixture or added separately as desired. It is preferred, however, to prepare the slurry directly by formation of the alkali metal formyl ketone in the methyl formate medium since this obviates purifying or recovering the alkali metal formyl ketone from the reaction mixture in which it is formed or

dissolving it in another solvent such as methyl alcohol. The ketone employed in preparing the alkali metal formyl ketone, of course, will depend upon the particular B-Iretoacetal which is desired, and any of the well-known ketones can be used such as acetone, methyl ethyl ketone, diethyl ketone, methyl vinyl ketone. Similarly any of the well-known alkyl formate esters can be employed such as ethyl formate or the like ; but, since methyl formate is employed as vehicle in the preferred process, the formate is desirably methyl formate in an excess amount whereby it fulfils the dual function of a reactant and vehicle. The alkali metal formyl ketone can be prepared eitectively trom either an alkali metal or an alkali metal alcoholate. The particular alkali metal will depend on the product desired although particularly good results are obtained using either sodium metal or a sodium alcoholate. Because of ease ot handling, the alkali metal alcoholates and particularly the alkali metal alkoxides are preferred. Typical examples of suitable materials include metallic sodium, metallic potassium, sodium methoxide, sodium ethoxide, sodium isopropoxide, potassium methoxide, potassium ethoxide, potassium isopropoxide and similar well-known alkali metals and alkali metal alkoxides. The alkali metal enolate is desirably prepared by slurrying the alkali metal alkoxfde and the formate, either with or without an inert solvent, such as petroieum ether, and then adding the ketone to the slurry. With acetone as the ketone, the alkali metal formyl acetone is formed as a creamy solid, which can be readily separated from the reaction mixture, although separation of the enolate prior to the subsequent reaction is not necessary for good results. The reaction bey the Retone, formate and alkali metal or alkali metal alcoholate pro. ecds readily ; and, due to the heat evolved, the reaction mixture is desirably ccoled to 15 25 C., particularly during the eariy stages. Best results are obtained by first mixing the methyl formate and the alkali metal or alkali metal alcoholate and then adding the ketone to the resulting mixture since the reaction is less violent and more readily controlled than when using a different order of addition. During the latter stages of the reaction, forced reflux can be employed for optimum results. By using theoretical quantities of the reactants the reaction proceeds almost quantitatively, and using an excess of methyl formate a thick slurry of alkali metal formyl ketone in the methyl formate is obtained. The alkali metal enolate of the I)-ketoaldehyde, (in the preferred method, in a slurry of methyl formate) is then progressively added to

a solution of anhydrous hydrogen chloride in methyl alcohol. The methanolic hydrogen chloride solution desirably has a noir- mality of 3 to 6 and is employed in a sufficient quantity to maintain the pH of the mixture below 1 and preferably from 0. 0 to below 1. 0 and so that the reaction mixture after addition of all of the enolate will have a pH below 1 and preferably between 0. 0 and below 1. 0 whereby the alkali metal formyl ketone contacts the methyl alcohol in the acidic medium only at such low pH. During addition of the enolate to the methanolic hydrogen chloride, the mixture is continually agitated to maintain the desired pH throughout the mixing, and the temperature of the mixture is maintained at or below 25 C. and preferably in the range of 15 to 25 C. In order to avoid localized areas of higher pH, the slurry is added progressively over a period of time which will vary with the quantity to be added and the degree of agitation employed. In the preferred process of the present invention an alkali metal formyl ketone is reacted under substantially anhydrous conditions with methyl alcohol in methyl formate and in the presence of sufficient hydrogen chloride to maintain the measured apparent pH of the non-aqueous reaction mixture below 1 throughout the reaction, which includes the time during which the alkali metal formyl ketone and alcohol are being admixed. Upon completion of the addition and with the pH maintained below 1, the reaction mixture is agitated and held at a temperature of from 15 to 25 C. until the reaction is substantially complete. Usually a period of from 2 te 6 hours is sufficient for completing the reaction. In the preferred method of the present invention the ~-ketoacetal formed in the reaction mixture goes into solution in the methyl formate and the solid alkali formyl ketone is gradually used up. At the pH of the reaction little or no triacetyl benzene is formed as a by product of the reaction. Upon completion of the reaction, the excess acid in the reaction mixture is neutralized carefully until the mixture has a pH not higher than 7 and preferably from 6. 0 to 6. 5. The neutralization can be accomplished in accordance with well-known practice such that close control of the pH is possible. Neutralisation is effected with an alkali metal alkoxide, which is an anhydrous base, in contrast with the use of aqueous solutions of sodium or potassium carbonate which lead to the formation of-ketovinyl ether or other by-products unless extreme care is exercised. Particularly good results are obtained by employing a solution of the alkali metal alkoxide, such as sodium methoxide, in an organic solvent such as methyl alcohol. Neutralization of the reaction mixture with a sodium alkoxide in non-aqueous media causes precipitation of large amounts of sodium

chloride. This is filtered from the reaction mixture in the usual manner, and entrapped p-ketoacetal is washed from the filter cake with solvent such as methyl alcohol. The (3-ketoacetal is then recovered from the neutralized mixture with the : mixture maintained at a pu of 6 to 7. Separation of the R-ketoacetal can be ejected by any of the well-known procedures such as adsorption or the like but is desirably effected by vacuum distilling solvent away from the etoacetal. If desired the -ketoacetal can then be redistilled for further purification. In the preferred form of the present invention any unused methyl alcohol and methyl formate vehicle is distilled away from the neutralised and filtered mixture, and the stripped -ketoacetal then vacuum distilled for further purification. The invention is illustrated but not limited b-f the following examples :- EXAMPLE.1. PREPARATION OF SODIUM FORMYL ACETONE a) A 1. 0 mole portion of methyl formate was charged into a reactor provided with a reflux condenser and an agitator. One mole of sodium methoxide was then slowly added to the methyl formate with the solution being cooled and agitated throughout the addition. After completing addition of the sodium methoxide, the mixture was agitated under forced reflux for an additional 15 minutes to form a thick white slurry. Slightly more than one mole of acetone was then added to the slurry over a period of about 15 minutes ; and, after addition, the mixture w.asrenuxed and stirred for one hour. At the end of the reflux period, the sodium formyl acetone which precipitated as a solid was separated from the reaction mixture and dissolved in methyl alcohol. b) The alkali metal enolate is readily prepared employing an alkali metal instead of the alkoxide. Thus, 48 grams of powdered sodium in 500 ml. of dry ether was cooled to a temperature of 10 C., and a mixture of 3 moles of ethyl formate and 2 moles of acetone was slowly added with stirring and cooling to maintain the lowered temperature. Atter addition of the formate-acetone mixture oevr a period of 90 minutes, the reaction mixture was allowed to stand overnight. The sodium formyl acetone was then filtered off, washed with ether and dried over calcium chloride. The product a cream coloured solid, weighed 205 grams=91. 5% yield of sodium formyl acetone. -IlETOBUTYRALDEHYDE DIMETHYL ACETAL A 5 to 6 normal solution of hydrogen chloride was prepared by dissolving 1. 1 moles of anhydrous hydrogen chloride in 200 cc. of

methyl alcohol. The methanol solution of sodium formyl acetone as prepared in a) was then progressively added to the methanolic hydrogen chloride over a period of about 30 minutes while the mixture was being stirred and the temperature maintained at 15-25 C. At the end of such addition, the measured pH of the mixture was in the range of 0. 0 to 1. 0. The reaction mixture was then stirred at a temperature of 20-25 C. for 4 hours to allow reaction to go to completion. Following the reaction, the mixture was neutralized by the careful addition of a solution of sodium methoxide in methyl alcohol until a pH of 6. 0-6. 5 was reached. The solution was then filtered to remove the sodium chloride which salted out, and the filter cake was washed with methyl alcohol. The resulting filtered product was then distilled, first at atmospheric pressure and a temperature of about 50 G, then under vacuum at 5 G. to remove solvent from the product. The resulting crude tobutyraidehyde dimethyl acetal was recovered and distilled at 55-56 C. at 8-10 mm. Hg. to give a purified product in 70% yield having N d 20= 1.41301.4162 and E 1 cm 1% (244 m?)=68 maximum and containing less than 0.1% water.The product contains only minor amounts of the f.-ketovinyl ether and no substantial amount of triacetyl benzene is formed during the preparation. -Similarly improved results are obtained with other alkali metal enolates of this and other -ketoaldehydes when reacted with methyl alcohol and hydrogen chloride in accordance with the present invention. The following example illustrates the preferred method of the present invention in which methyl formate is present in the reaction mixture (1). EXAMPLE 2 A mixture of sodium methoxide and methyl formate was prepared by adding 10. 31 kilograms of methyl formate to 1 kilogram of sodium methoxide in a suitable reactor maintained at a temperature of 10 -15 . The mixture was agitated and refluxed for 15 minutes following the addition. Acetone in a total quantity of 1.088 kilograms was then slowly added to the mixture, and the resulting mixture was refluxed for two hours. At the end of this time, a thick slurry of sodium formyl acetone in methyl formate was obtained. A solution of hydrogen chloride in methyl alcohol was prepared in a second reactor by dissolving 0. 76 kilogram of anhydrous hydrogen chloride in 3. 315 kilograms or anhydrous methyl alcohol. With the methanolic hydrogen chloride at a temperature of 15 C., the slurry of sodium formyl acetone in methyl formate was slowly added over a period of about 30 minutes, during which time the mixture was agitated and maintained at

a temperature of 1525 C. The reaction mixture at the completion of the addition of the slurry had a pa in the range of 0. 0 to 1. 0. This strongly acid mixture was then agitated at a temperature of 2025 G for 4 hours to allow completion of the reaction. At the end of the time, a solution of 0. 10 kilogram of sodium methoxide in 0. 12 gallons of methyl alcohol was slowly added until the pH reached a value of 6 to 7. The precipitated sodium chloride was then filtered out of the neutralized mixture, and the filtrate was fractionally distilled under a partial vacuum to remove the methyl alcohol and methyl formate. The residue of crude jS-ketobutyraldehyde dimethy acetal was again filtered and then fractionally distilled at a temperature of 55~-56~ C. and a pressure of 8-10 mm. Hg. to give 1. 88 kilogram of product having N D 20=1.4130-1.4162; E 1 cm 1% (244 m?)=38-68 and containing less than 0.1% of water. This represented a yield of 81% based on the original sodium methoxide. Similar results are obtained in preparing other/3-ketoacetals in methyl formate media, and the invention thus provides a simple and economical method for improving the yield of ~-ketoacetals. When the reacuon is effected in methyl formate according to the preferred form of the present invention, an increased yield of j6-ketoacetal over processes where the methyl alcohol acts both as vehicle and reactant or where some other solvent is used, is obtained. The reason why the use of methyl formate, in which the alkali metal formyl acetone is insoluble and the fl etoacetal is soluble, promotes the formation of ~-ketoacetal in higher yields than expected is not understood at this time. The exact reasons why the formation of ~-ketovinyl ether and triacetyl benzene is obviated and the yield of ketoacetal is raised to as much as 70% or more by the process of the present invention are not clearly understood. The improved results obtained appear to be dependent upon the particular combination of conditions and reactants, however, since the substitution of ethyl alcohol for methyl alcohol greatly decreases the yield of /3-ketoacetal. Also reacting at higher pH values results in formation of large amounts of triacetyl benzene and -ketovinyl enher. This is particularly surprising since acid is ordinarily employed to cause formation of triacetyl benzene and increasing the acidity over that employed heretofore would therefore be expected to increase the formation of triacetyl benzene rather than to obviate its formation in objectionable amounts. It is further unexpected to find that the pH conditions throughout the bringing together of the reactants exert such a marked influence on the yield of -ketoacetal and the presence or absence of substantial amounts of -ketovinyl ether. Thus, employing exactly the same relative amounts of reactants, the results are vastly

different when the sodium enolate of the -ketoaldehyde is progressively added to the anhydrous methanol containing the anhydrcus hydrogen chloride so that the pH is always below 1 and preferably between 1. 0 and 0. 0, from the results obtained when the alcoholic hydrogen chloride is added to the sodium enolate of the -ketoaldehyde, even though the final mixture contains exactly the same amount of each reactant. Thus, when the order of addition is reverse, yields of -ketoacetal below 25 % are obtained and equal or greater amounts of triacetyl benzene and jS'-ketovinyl ether are formed. Similarly, when the reaction mixture is neutralized following completion of the reaction, the pH must be carefully adjusted to the range of 6 to 7 and the -ketoacetai separated at this pH or a substantial amount of the B-ketoacetal converts to -ketovinyl ether or to other unidentified products which appear to be polymeric in nature. The present invention thus provides a method of preparing G ketoactals by a novel process which greatly facilitates the production of commercial quantities of the dimethyl acetal of -ketobutyraldehyde of good quality and at low cost. The present invention thus provides a simple but highly effective method of preparing -ketoacetals in greatly improved yield and free of objectionable amounts of undesired side products such as triacetyl benzene and R-ketovinyl ethers. The preferred method of the present invention minimises the operative steps in the process of preparing -ketoacetals. Dimethyl acetals of $-ketoaldehydes are useful intermediates in the synthesis of a, p- unsaturated aldehydes, and the -ketoacetals have found particular use in the synthesis of pharmaceuticals including antibiotics such as sulphamerazine and vitamins such as vitamin A. What we claim is : 1. A method of making the dimethyl acetal of an aliphatic -ketoaldehyde as herein defined which comprises making a substantially anhydrous mixture (1), comprising an alkali metal enolate of the -ketoaldehyde, anhydrous methyl alcohol and anhydrous hydrogen chloride, allowing the mixture (1) to react, neutralising the reacted mixture (2) and separating the dimethyl acetal of the -ketoaldehyde from the resulting mixture (3), said method being characterized in that said enolate is added with mixing to a solution of such an amount of said hydrogen chloride in said methyl alcohol that the pH of the mixture (1) is maintained below 1 throughout the mixing, the mixture (1) is allowed to react at said pH at a temperature not above 25 C., the pEi of the reacted mixture (2) is raised to from 6 to 7 by the addition of an alkali metal alkoxide and the resulting mixture is

maintained at said latter pH while the dimethyl acetal of the '-ketoaldehyde is separated therefrom.

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* GB784611 (A)

Description: GB784611 (A) ? 1957-10-09

Curing of polymerisable materials




PATENT SPECIFICATION Inventors: GEOFFREY LAMBSIN FOSTER and PETER FRANCIS NICKS 784,611 Date of filing Complete Specification: Sept 19, 1955. E 2 Application Date: Sept22, 1954 No 27372/54. 3 X > Complete Specification Published: Oct 9, 1957. Index at acceptance:-Classes 2 ( 6), P 4 A, P 4 D( 2: 3 A), P 4 K 8, P 4 P( 1 B: 1 C: 1 E 2: 5: 6 X), P 8 A, P 8 D( 2 A: 2 82: 5), P 8 K( 4: 8), P 8 PI(B: C: E 2: X), P 8 P( 5: 6 X); and 140, A( 2 K 1 C: 5 G 9: 18). International Classification:-B 29 d C 08 f. COMPLETE SPECIFICATION Curing of Polymerisable Materials We, IMPERIAL CHEMICAL INDUSTRIES

LIMITED, a British Company, of Imperial Chemical House, Millbank, London, S W l, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to the curing of polymerisable esters whose polymerisation is inhibited by the presence of oxygen. The polymerisable esters with which we are concerned in this invention include monomeric esters of methacrylic and acrylic acid and polyesters derived from a polyhydric 15 alcohol, a dicarboxylic acid and methacrylic or acrylic acid, for example, resins described in British Patent 607,888, having the general formula: o O Gfl=C&-CO-O G ti-CH a O O r C-0 H 1 21 where N is 0 or a small positive integer, i e. between 0 and 5. It is known that polymerisable polyesters, having dissolved in them polymerisable substances such as styrene or a diallyl ester or certain methacrylates, can be gelled in the presence of organic peroxides, and for example, cobalt naphthenate Naphthenates and similar salts of metals other than cobalt have also been used, including lead, iron, copper and manganese All of these salts are known as "driers" It is also known to use a hydroperoxide and a "drier" to cure certain mixtures comprising a copolymerisable mixture of one or more alkyd resins comprising an c,#-unsaturated acid and one or more substances comprising the CH 2 = C< groups This latter process is stated to effect curing at room or higher temperatures. The present invention concerns a method of overcoming the characteristic air inhibition of polymerisable methacrylate and acrylate esters. For example, it is known that with certain resins used in laminated productions the lPrica 3 s 6 d l ? I L -') > N curing or polymerisation process in the exposed layers is inhibited by the presence of atmospheric oxygen Similar difficulties arise when coatings are formed comprising polymerisable methacrylate and acrylate esters. We have now found that the air inhibition associated with polymerisable methacrylate and acrylate esters can be overcome by effecting the curing of the esters in the presence of a hydroperoxide curing catalyst, a "drier" and an ester derived from an allyloxyalkanol Catalysts include aliphatic aromatic and cycloaliphatic hydroperoxides and examples of such catalysts for use with the additive include cyclohexyl hydroperoxide, methyl ethyl ketone hydroperoxide, di-isopropyl benzene hydroperoxide, paramethane hydroperoxide, tertiary butyl hydroperoxide and cumene hydroperoxide

The most satisfactory catalysts from the view point of efficiency are cyclohexyl hydroperoxide and methyl ethyl ketone hydroperoxide Satisfactory "driers" for use in the invention include cobalt or lead naphthenates. Examples of the additive, that is to say, esters derived from allyloxyalkanols, include polyesters of a-allyl glycerol and a dicarboxylic acid, in particular c-allyl glyceryl phthalate, -allyl glyceryl succinate, allyloxyisopropyl methacrylate and allyloxymethyl methacrylate. Of these we find the polyesters a-allyl glyceryl succinate and a-allyl glyceryl phthalate to be the most suitable since they are non-volatile at normal temperatures and do not decrease the viscosity of the laminating resin A further important practical advantage is that they are relatively odourless whereas some of the monomeric compounds possess pungent lachrymatory odours which can make their usage unpleasant. The proportion of additive used with the polymerisable methacrylate and acrylate esters can be varied between fairly wide limits but we find additions of 5-20 % by weight of additive based on weight of polymerisable ester to be most useful The viscosity of the preferred polyester additives is high and the molecular weight of these additives is preferably between 7000 and 10,000. A possible explanation of our invention is that the allylic compound absorbs atmospheric oxygen at a rate greater than the rate at which oxygen diffuses, by solution, into the system hence the actual curing reaction takes place under substantially anaerobic conditions. Some support for this theory is to be found in the fact that it is known that the formation of hydroperoxides by addition of oxygen to allylic compounds is a facile reaction More particularly esters derived from allyloxyalkanols in which the methylene groups adjacent to the ether oxygen are very prone to attack by oxygen with the resultant formation of hydroperoxides. It is possible that the "driers" assist our additives in overcoming air inhibition but they are not effective themselves in the absence of our additive. For the preparation of laminated materials the additive can be mixed with the bulk of the laminating resin or a solution in, for example, glycol dimethacrylate may be sprayed or brushed onto the outer layer of the laminated body A third procedure involves the mixing of the additive with the laminating resin used to impregnate the outer layers of the laminate. The catalyst and "drier" may be added to the methacrylate polyester resin before the allyloxyalkanol ester or the three compounds may be added individually or all together as a mixture The glycol

dimethacrylate can be used if necessary and is a polymerisable solvent. Our invention is illustrated by the following Examples in which parts are expressed by weight. EXAMPLE I. A nineteen layer laminate was prepared on a solid former using loom state glass cloth and impregnating throughout with Resin A: Ethylene glycol methacrylate/phthalate resin prepared as described in Example 7 of B P 607,888 90 a-allyl glyceryl phthalate 10 Cyclohexyl hydroperoxide 4 Lead and cobalt naphthenates ( 24 % and 06 % respectively by weight of resin calculated on the metal). Resin A The laminate was exposed to the air and the follows Fifteen layers of glass cloth were surface was tack free in six hours impregnated with Resin B and each laid on the solid former The top four layers of glass EXAMPLE II cloth were then each impregnated with Resin A nineteen layer laminate was prepared as A and added to the original fifteen layers. Ethylene glycol methacrylate/phthalate resin as used in Example I 100 parts by wt Resin B "Drier" and catalyst as in Example I. The laminate cured satisfactorily and the sur succinate and similar results were obtained. face was found to be tack free in six hours. EXAMPLE III. Example I was repeated using in place of a.-allyi glyceryl phthalate, a-allyl glyceryl EXAMPLE IV. A similar ten layer laminate was prepared using Resin B throughout When prepared, the 85 exposed surfaces of the laminate were sprayed with a solution containing: 784,611 784,611 Glycol dimethacrylate 90 Solution C a-allyl glyceryl phthalate 10 The solution formed a film about 5 thou inch thick and the laminate appeared to be cured satisfactorily and the surface was again tack free in six hours. EXAMPLE V. Example IV was repeated using a-allyl glyceryl succinate in place of a-allyl glyceryl phthalate and similar results were obtained. EXAMPLE VI. A ten layer laminate was prepared as in Example IV The surface was brushed with Solution C Results were again satisfactory, the applied film being of the order of 10 thou. inch thick. EXAMPLE VII. A ten layer laminate was prepared as described in Example IV The surface of the laminate was brushed with Resin A Results were again satisfactory and the film comparable with that obtained in Example VI.

It is essential, when employing the coating techniques, that the exposed surface of the methacrylate polyester resin containing mass be completely covered with the solution containing the additive if the air inhibition characteristics of the methacrylate polyester resins are to be overcome The process as used in Examples IV, VI and VII has the advantage that the amount of additive required to overcome the air inhibition is very small and has been shown to be of the order of 9 mgm of additive per square inch of laminate. Our invention is also applicable to coating and impregnating compositions where air inhibitiont is in some cases a problem. EXAMPLE VIII. A sample of Resin A was poured onto tinplate to form a thin film This film cured satisfactorily in six hours. EXAMPLE IX. A further sample of Resin A was stored in a 3 " x 1 " tube open at one end and this cured to a hard, tack-free, state in five hours. EXAMPLE X A solution of 50 parts of a-allyl glyceryl phthalate and 50 parts of methyl methacrylate was treated with catalyst and "drier" as in the above Examples A sample was brushed onto tinplate and the film cured in air in three and a half hours to give a good, hard, tough, film. EXAMPLE XI. Example X was repeated using in place of methyl methacrylate glycol dimethacrylate A similar result was obtained except that the film took about four and a half hours to cure.


* GB784612 (A)

Description: GB784612 (A) ? 1957-10-09

Esters of organic dithiophosphinic acids and methods for preparing same




PATENT SPECIFICATION Inventors: GEORGE RUSSELL NORMA N, WILLIAM MONROE LE SUER and THOMAS WII,,L/AM MASTIN 784 Date of Application and filing Complete Specification: Oct 7,1954. No 28895/54. ;j// Complete Specification Published: Oct 9,1957. Index at acceptance:-Class 2 ( 3), C( 3 X: 4). International Classification:-C 07 f. COMPLETE SPECIFICATION Esters of Organic Dithiophosphinic Acids and methods for preparing same We, THE Lu BRIZOL CORPORATION, a corporation organized and existing under the laws of the State of Ohio, United States of America, of Lakeland Boulevard, Wicldiffe, in the State of Ohio, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which lit is to be performed, to be particularly described in and by the following statement:- This invention relates as indicated to esters of dithiophospbinic acids and methods for preparing same. It is a principal object of our invention to provide new compounds of the character described by a process which is characterized by relatively high yields and low cost due to the fact that the process does not ordinarily require any particularly special conditions nor the use of a catalyst. Other subjects of the invention will appear as the description proceeds. To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly po Lnted out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed. The esters of dithiophosphinic acids can be defined more exactly by

the formula: R 55 Rho S-R 11 wherein R and R' are the same or different organic radicals each of which is attached to phosphorus by one of its carbon atoms, and lPrice 3 s 6 d J R is an organic radical attached to a sulphur atom which is attached to thle phosphorus atom In most instances, R and R' are preferably hydrocarbon radicals such as alkyl, aryl, alkaryl or arylalkyl radicals (such as cyclic or acyclic hydrocarbon radicals) of from 1 to 60 carbon atoms The radical R is a non-benzenoid organic radical, such as e.g fatty acid ester, or quinone radicals. Broadly stated, ithe process of this invention comprises reacting at least one dithiophosphinic acid with an organic material containing at least one non-benzenoid unsaturated linkage. More particularly the method of this invention relates to preparing esters of dithiophosphinic acids which comprises reacting: A a dithiophosphinic acid having tfhe following structure: RI S wherein R and RI are the same or different organic radicals each attached to phosphorus by one of its carbon atoms; with a compound B containing carbon hydrogen and at least one additional elemnent and having at least one non-benzenoid unsaturated linkage; in such proportions and at such temperature as to cause the reaction to proceed without substantial decomposition of the esters formed and for a length of time such that the acidity of the reaction mass is substantially reduced. Throughout the following description of this invention and in the appended claims, the term "non-benzenoid unsaturated linkage" is intended to include the olefinic and quinoid linkages. 612 2 784,612 The diorgano dithiophosphinic acids used as starting materials in the process can be prepared by the reaction of Grignard reagents with phosphorus pentasulphide (see Organophosphorus Compounds, G M Kosolopoff, page 135, John Wiley & Sons, New York, 1950) A representative method for the preparation of diorgano dithiophosphinic acids involves the reaction of an aromatic compound with phosphorus pentasulphide in the presence of molar amounts of aluminium chloride, followed by decomposition of the resulting complex with water las described in the co-pending U S Application of Miller et al, " Organic dithiophosphinic Compounds and Methods for preparing Same," Serial No. 406,323, filed January 26, 1954, and owned by the Assigneel. THE NON-BENZENOID UNSATURATED STARTING MATERIALS. These starting materials which may be used in the process include all those organic compounds containing carbon, hydrogen and at least one additional element which are characterised by the presence of at least one olefinic, or quinoid linkage, that is, by at least one unsaturated

double bond between adjacent carbon atoms, although these materials may additionally contain elsewhere in the molecule aromatic or cyclic groups as well as inorganic elements or substituents. Of the foregoing non-benzenoid unsaturated starting materials acyclic compounds are preferred. PROCEDURE. The particularly selected thiophosphinic acid is combined in a suitable reaction vessel with the particularly selected non-benzenoid unsaturated material, such combination being in the first instance a physical admixture or solution at room temperature Since the stoichiometry of the reaction usually requires one mole of thiophosphorus acid reactant per mole of unsaturated organic reactant, these proportons are the ones wost often employed. However, an excess of either reactant may often be used to advantage so as to force the reaction to substantial completion The excess reactant can be removed, if desired, by any convenient means, e g, as by distillation. Generally the reaction does not proceed until the reaction mass is heated to about 40-50 C.; however, in certain instances the reaction commences at room temperature Any suitable temperature above that just given up to about 2500 C may be used The reaction will generally proceed sufficiently rapidly at temperatures in the lower portion of the range given above, that is, at 1000 C to 110 C. so that the higher temperatures within that range need not be employed In general, the lower temperatures falling within the range above stated are preferred since they are easier and more economical to use and have a lesser tendency to cause decomposition of the products After the reaction mass has been heated to the point where reaction is initiated the reaction will proceed either endothermically or exothermically, depending upon the character of the reactant materials When using an 70 olefinic material containing activated double bonds, the reaction usually proceeds exothermically in which case it may be necessary to cool the reaction mass or bring the reactants together at such a slow rate that overheating 75 of the reaction mass is prevented In such cases, however, after the main exothermic reaction has subsided, it will usually be found desirable to further heat the mass for a short time, usually at least about one-half hour, to 80 maintain it within the range given above until the reaction has been completed. In other cases and usually where the nonbenzenoid unsaturated reactant material is of high molecular weight, the reaction may 85 require the application of heat during the entire reaction time. In instances where the non-benzenoid unsaturated material is a high molecular weight polymer, e g, polymeric materials of normally 90 highly-viscous, rubber-like, or solid physical states, it has been

found advantageous in certain cases to carry out the reaction with the selected dithiophosphinic acid in the presence of a mutual solvent By the use of such 95 mutual solvent, all of the molecules of the reacting materials may be brought into intimate contact with each other under conditions most favorable for reaction. A general procedure has been worked out 100 which has been found to be eminently satisfactory for producing materials of our invention from a wide variety of unsaturated polymeric substances: The selected polymer (one unsaturation 105 gram-equivalent) is dissolved in a sufflicient quantity of a suitable, non-reactive solvent (e g, benzene and substituted benzenes such as toluene, xylene, ethyl-benzene, chloro-benzene, nitro-benzene, and the 110 like) to yield a non-viscous solution The percent by weight of solvent in such nonviscous solution has been found to vary from about 15 % to about 95 %, depending on the viscosity-heightening characteristics 115 of the particular polymer dissolved therein. number of grams of polymer equivalent to one non-benzenoid unsaturated linkage. The selected dithiophosphinic acid (one 120 mole or slightly in excess thereof) is added to the solution of the polymer, and the whole is heated for a number of hours on a steam bath. The product is then precipitated from solu 125 tion by the addition of an approximately equal volume of methanol Depending on the molecular weight of the particular polymeric starting material, the precipitated product has been found to vary in physical state from a viscous 130 784,612 784,612 3 oil to a rubber-like mass. The solvent layer, which consists of a mixture of the chosen solvent, methanol, and any unreacted dithiophosphinic acid, is drained off The acid no of the product is determined, and if this indicates the occlusion of substantial amounts of dithiophosphinic acid, the product is dissolved in the chosen solvent and re-precipifated with methanol in the manner previously described In actual practice it is quite difficult to remove the last traces of dithiophosphinic acid For most applications, however, the relatively small proportion of dithiophosphinic acid remaining has not been observed to exert a deleterious effect. The product, isolated in the manner set forth above, is re-dissolved in a quantity of the chosen solvent and then further processed according to one or the other of the following two finishing operations: (A) The solution is placed in a distillation vessel and heated until its volume has been reduced about one-half The distillate is a mixture of the chosen solvent plus substantially all of the lower boiling methanol contaminant originally present in the distilland.

The final product is the distilland, which comprises a solution of the product in the chosen solvent. (b) The solution is placed in a distillation vessel and heated under reduced pressure until the solvent has been removed. The final product is the distilland, which comprises substantially solventfree product. Depending on the use to which the product is to be put, we may select one or the other of the two final processing operations detailed above Where the intended use of the product is an addition agent for fuels, lubricants, and plasticizers we prefer to follow processing operation (A) When processed in this manner, the product usually displays its maximum solubility in organic materials. From the foregoing it will be observed that the process comprising the invention is characterized in that the conditions thereof are such that it may be carried on at a relatively low cost and in equipment which is relatively inexpensive The fact that no catalyst is required is an important factor in making the process particularly attractive from a commercial point of view. In the foregoing, the amount of nonbenzenoid unsaturated material and thiophosphinic acid used in the reaction was in substantially equimolecular proportions,. usually a slight excess of non-benzenoid unsaturated material being used in order to insure completion of the reaction with the dithiophosphinic acid and since the excess of non-benzenoid unsaturated material can be recovered at the conclusion of the reaction. When the unsaturated material contains a plurality of non-benzenoid unsaturated linkages in a single molecule, only enough of such organic material need be used as is necessary to provide a slight excess thereof on the basis of one non-benzoid unsaturated linkage in such material per mole of the thiophosphorus acid. Whether the reaction is endothermic or exothermic, the mass will be maintained at the reaction temperature long enough so that the acidity of the reaction mixture is substantially reduced When the acidity has decreased to a substantially constant value completion of the reaction is indicated. In the application of our improved process to the production of a wide variety of different materials, we have been able to work out a standardized procedure which is illustrated by the following example: EXAMPLE 1. Preparation of: Omega-carbomethoxyheptadecyl ester of diphenyl dithiophosphinic acid. sio O S o CH 3-(c H 2)a-CH -(c H 2)7-C-o-CH 3 One mole ( 330 g) of substantially pure 90 diphenyl dithiophosphinic acid, having the

following analysis: having the following analysis: Analysis: % sulphur % phosphorus Acid number Calculated Found 25.6 12.4 223 24.9 12.2 173 was heated with one mole ( 296 g) of methyl oleate for 10 hours at 90 -100 C, stirring continually The acid number of the mixture 100 was reduced from 87 5 to 35 in this time. After cooling, the whole was washed once with about an equal volume of 5 % aqueous sodium carbonate, a small amount of benzene and n-butanol being added to facilitate separa 105 tion Thereafter, the organic layer was washed three times with water and subjected to distillation as in the previous step to remove solvents The dark-colored liquid which remained in the distillation flask weighed 501 g 110 It was the substantially pure complex dithiophosphinate ester having the chemical structure shown at the head of this example. 784,612 4 784,612 Analysis: % sulphur % phosphorus Acid number Calculated Found 10.2 10 9 4.95 5 08 8.7 EXAMPLE 2. Preparation of Dihydroxyphenyl diphenyl ditiliophosphinic acid. C/X OH Diphenyl dithiophosphinic acid ( 428 g, 1 3 moles of the same acid used in example 1) was dissolved in 500 ml of benzene, and to this solution was added gradually a solution of p-quinone ( 140 4 g, 1 3 moles) in 750 ml. of warm benzene The rate of addition was suitably regulated to keep the reaction mixture at about 50 C (an exothermic reaction). After the addition was completed, thie whole was stirred for 1 5 hours at 45 -50 C, allowed to cool, and then washed with 5 % aqueous sodium bicarbonate solution and water The organic layer was extracted with 800 g of 20 % aqueous sodium hydroxide, and the aqueous extract was acidified with hydrochloric acid A quantity of benzene was agitated with the acidified extract, and the benzene layer therefrom was washed and subjected to distillation to remove volatile material as in the previous example. The pale-yellow semi-solid product which remained in the distillation flask weighed 425 g It was the substantially pure dihydroxyphenyl ester of diphenyl dithiophosphinic acid. The Grignard reagent thus prepared was added slowly, with stirring, to a suspension of phosphorus pentasulphide ( 222 g, 1 mole) in anhydrous ether, allowing the mixture to reflux gently by the heat of reaction After the addition was completed, the whole was stirred for 1 hsur under reflux ard 4 hours roeam temperature, and then digested with an icewater-ammonium chloride mixture which was acidified after a short time with a quantity of hydrochloric acid The organic layer was separated, washed with water, dried ever anhydrous magnesium sulphate,

and filtered A portion of the ether was removed from the filtrate at rocm tempzrature and reduced pressure (ca 100 m Hg) admitting a slow stream of nitrogen toe assist in the removal of the ether The liquid which remained in the flask weighed 1200 g, had an acid number of 98, and was substantially pure di-( 2-ethyl-hexyi) dithiophosphlinic acid ( 2 1 moles) in ether solution. p-Quinone ( 226 g, 2 1 moles) was added slowly to the acid solution prepared above, allowing the reaction mixture to reflux gently from heat of reaction After the addition was completed, the whole was stirred for 1 5 hours at about 500 C The purification by washing and caustic extraction was then carried out in the same manner outlined in example 2. The brown, viscous liquid which remained in the distillation flask weighed 260 g It was the substantially pure dihydroxyphenyl ester of di-( 2-ethyl-hexyl) dithiophosphinic acid as shown by analysis: Analysis: % sulphur ' phosphorus % hydroxyl Calculated Found 14.87 7.21 7.91 13.0 7.31 6.18 Calculated Found 17.88 8.66 9.5 17.15 8.63 8.74 EXAMPLE 3. Preparation of Dihydroxyphenyl ester of di-( 2-ethyl-hexyl) dithiophosphinic acid. OH CH PS (CH 3-CH 2-CH 2-CH 2-CH-CH 2-)2 S OH A Grignard reagent, 2-ethyl-hexyl magnesium chloride, was prepared in a well-known manner from 2-ethyl-hexyl chloride ( 594 g, 4 moles), magnesium turnings ( 97 2 g, 4moles), and a catalytic amount ( 5 g) of ethyl bromide in anhydrous ether solution. Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.


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