C&EN A N N U A L REVIEW—1951

Hampered by raw materials shortages, a 20%

increase over 1950 was reported for production of

Synthetic Détergents FOSTER DEE SNELL, Foster D. Snell, Inc., New York, Ν. Y.

U V N D E T S ' rivalry to soap in the detergent field increased in 1951. Greater produc­tion of petroleum-based syndets and de­creased soap production freed more fats and oils during the last year, so that the latter are in ample supply. Although shortages of raw materials for syndet manufacture limited production somewhat, an increase for 1951 ovei 1950 of about 20'"t occurred. Soap production tonnage declined about the same amount th?t syn­dets increased.

Revised consumption figures for the en­tire industry in 1950 follow in comparison with expected 1951 production. Exports are excluded.

million pounds 1950 1951

Solid soap Syndets

Total

2,955 1,250 4,205

2,780 1,500 4,280

Per capita consumption of detergents has averaged 26.7 pounds over the past 10 years and is about 27.7 pounds in 1951.

From a semichemical industry which consumed mainly caustic soda and fats to produce soap and glycerol, the detergent industry has in recent years become a large user of sulfuric acid and benzene, unsaturated hydrocarbon gases such as propylene, and ethylene oxide. The 1951 syndet production reflects limitations of the supply of sulfur and benzene for manu­facture, of tripolyphosphate and tetra-sodium pyrophosphate for building. The Defense Plant Administration has aided expansion of industrial facilities along many lines, including elementary phos­phorus for munitions. In contrast it has not encouraged expansion in t he detergent field, nor in the related field of polyphos­phate production. New end-product ca­pacity in 1951 included a $25 million plant in Los Angeles in June for soap, syn­dets, and shortening, and a soap and syn­det plant in Sacramento.

In terms of retail sales, syndets already have about half the volume, the major field of soap which is less affected being the bulk marlcoi: such as laundries. Soap Picture

As of late 1951 tallow had dropped from 12 cents a pound in late 1950 to 8 cents

a pound, coconut oil from 18 to I o cents a pound, and soybean oil from 8 to 6 cents a pound. Some decline in soap prices re­sulted. The saving in fat and oil consump­tion by the decrease in soap requirements is reflected in the import-export situation. Just before World \V ar Π the U. S. was a net importer of fats and oils to the extent of about 1.5 billion pounds a year. \ \V are now net exporters to the extent of about one billion pounds a year. Imports consist mainly of coconut oil, palm oil, and castor oil; exports are mainly edible oils, bu t since \Yorld War II has included tallow and grease.

T h e price of glycerol reflects soap pro­duction but is modified by synthesis. In general, prices are about the same as at the end of 1950, b u t with smaller spread. Production of synthetic glycerol is esti­mated to have been about 40 million pounds last year. In early 1951 glycerol was in tight supply, due in part to loss of imports from Argentina. In the last half of the year imports began to arrive, from which one assumes that the requirements of Europe for glycerol had pretty well been met.

Deodorant soaps now include mechan­ic's hand soaps. Infrared radiation is used commercially to reduce the time required for conditioning ba r soap for pressing. A new raw material for manufacture of laun­dry and textile soaps is a fractionated tall-oil rosin acid, containing 70r/r of rosin acids and 3 0 % of fatty acids.

Products in which soap and syndets arc both present are only minor in volume. A new all-purpose cleaner contains soap, syndet, and polyphosphate. A concen­trated liquid soap is made more viscous by addition of a nonionic surfactant plus 1% of polyphosphate. Another aspect of the soap-syndet picture is that some house­hold cleaners sold under well-known brand names arc based on soap in some areas, on syndet in others.

Syndet Picture T h e great bulk of syndet production is

of petroleum-based alkyl aryl sulfonates. New capacity for alkane production from benzene and a C12 fraction came into operation in 1951 and further expansion

is under \va\ tor production as late as mid-1952. Further units for sulfonation of the hydrocarbon have been constructed during the last year .

Production ot nonionics, although still small in comparison with anionics, took a big jump in '51.

Syndet Raw Materials Short While raw materials for soap were in

ample supply, after recovery from the al­kali strike of 1950, syndet raw materials were and still are tight.

The shortage of mined sulfur early in *51 stimulated i ts recovery from other sources. Thus w e have Frash-process sul­fur at $20 a ton, that from pyrites at close to $28 and some from natural gas as high as $35 a ton. T h e greatest new source of sulfur is its recovery from natural gases containing hydrogen sulfide. Recovery in petroleum refineries is predicted to fur­nish 5500 tons m o r e in 1951 than is neces­sary to supply t h e needs of that industry. This is expected t o become nearly 200,000 tons in 1952 from that source. So success­ful has American industry been in supply­ing sulfur from n e w sources that in spite of the complex sulfur price, tha t for sul­furic acid was t h e same at the end of 1951 as at the end of 1950. Last summer syn­dets were taking 15,300 tons of sulfuric acid a month, 50O tons monthly more than ν in 1950. Recent discovery of new sulfur domes may curtail plans for further in­stallations of sulfur recovery systems and displace some high-cost recovery from natural gas. U. S. capacity for sulfur pro­duction will show a net increase of 1 5 % by 1953 over January 1951. A major ex­port market to the United Kingdom is dwindling and will practically disappear by 1954-5.

Benzene The present benzene requirement for

syndets is about a million gallons a month. In 1951 the to ta l benzene demand was for 222 million gallons, the supply 212 million gallons, t h e déficit 13 million gal­lons. Tlnis syndets account for less than 6 % of the national demand. By 1953 the domestic supply will b e about 6 5 % greater than the potential supply as of January

30 C H E M I C A L A N D E N G I N E E R I N G N E W S

DEVELOPMENTS IN THE CHEMICAL AND PROCESS INDUSTRIES

1951. This will include 130 million gallons from petroleum, taking the place of sub­stantial present imports. As of September production was approximately 12% from petroleum, 259c from tar distillers, t h e balance from coke ovens. T h e overall in­crease from petroleum was 2 5 % over t he previous month. Quoted prices of benzene increased about 2 0 % during the year, bu t contract and spot sales were in many cases at a substantially greater advance. Benzene has been more critical in syndet production than the short supply of sul­furic acid. The price of alkane remained the same.

With DPA-essential munitions phc^-phorus available bu t not required, a new plant for production of DPA-nonessential polyphosphates came into production at Lawrence, Kan., last summer. Other plants are under construction by the same com­pany and two other major phosphate-pro­ducing companies. Based on the figures for the first eight months of ' 51 , produc­tion for the year is estimated at 179,328,-000 pounds of te t rasodium pyrophosphate, and 597,456,000 pounds of tripolyphos-phate. Ninety pe r cent of the tripolyphos-phate and 85% of the tetrasodium pyro­phosphate go into detergent building. Polyphosphates are present in proportions up to 5 0 % in heavy-duty syndet products .

Sodium Carboxymethylcellulose Another important ingredient for syn-

dets—sodium carboxymethylcellulose—has been freely available. It promotes the d i s ­persing power of a syndet solution a n d lessens redeposition, when used in amounts up to 5 % of the total. So generally recog­nized is its function tha t a product com­bining alkyl aryl sulfonate with C M C a p ­peared for bulk sales recently.

The great bulk of syndet production is still as the spray-dried or drum-dried granular product . However, l ight-duty liquid detergents suitable for dish wash­

ing, washing painted surfaces, e tc . , are increasingly popular . Several new brands appeared in the last year. Production of liquid syndets in '51 was more t h a n 5 0 % above that of *50.

A new milled toilet bar syndet processed in conventional soap equipment is based on an alkyl aryl sulfonate. Test sales ap­peared in 1951. T h e product contains soy lecithin as detackifier, cornstarch for hardening, and talc to provide slush re­sistance.

A well known b rand-name syndet for­merly fat-derived has been changed to an alkyl aryl sulfonate. A new sudsless solid syndet appeared this year to compete for use in automatic laundry and disbwashing machines, wi th those already on t h e mar­ket. It is in tended also to compete with the usual sudsing heavy-duty detergents , so is a departure from the usual alkaline-salt compositions of the average product tor automatic dishwashing.

In the dairy industry ma in of the alka­line-salt cleaners formerly used contain added quaternary ammonium compounds as sterilizing agents. Cationics a re now also used to a considerable extent in steril­izing bottles, dishes, coffee urns, ice-cream scoops, etc., in d r u g stores, restaurants , and the bakery industry.

A notable development in t h e syndet field is the product ion of relatively low-cost nonionics, which is making t h e m in­creasingly compet i t ive with alkyl aryl sul­fonates. The majority of nonionics are now combinations of a hydrocarbon fraction with a chain from several moles of ethylene oxide. The lat ter is readily available from the petro-chemical industry at t h e stable price of 18 to 19 cents a pound. T h e hy­drocarbon fraction is obtained from petro­leum, rosin acids, fatty acids, alkyl phe­nols, etc . A new plant for production of nonionics uses a cont inuous process for production of about 2 million pounds a year.

Hydrocarbon fractions which have been used in the past require a chain of 10 to 12 ethylcne-oxide molecules to give the correct polar-nonpolar ba lance for good detcrgency. This resulted in a l iquid prod­uct. An increase in the proportion of ethyl­ene oxide would give a product with poor detergency. New nonionics are p roduced with a different hydrocarbon fraction selected to give both a solid product and effective detergent properties. Nonionics —by themselves usually low in foaming power—have been modified to heighten this property. As with anionics, sodium carboxymethylcellulose has been found to he a very effective addition to nonionics, particularly when used in ha rd water . T h e F D A has quest ioned the suitability of some nonionics for use in shampoos.

Because of their stability, their versa­tility, and the possibility of tailoring them to meet particular conditions, nonionics are finding special uses. An example is the use of a blend of nonionics in a dry-cleaning liquid so formulated as to per­mit a 2:1 solvent to water ratio result ing in a water-in-oil emulsion. This increases the efficiency of the dry-cleaning process by permit t ing increased wet t ing by the aqueous medium in addition to t he fat-dissolving action of the solvent.

Detergency Κ valuation T h e most used method for evaluating

detergent effectiveness in the laboratory is with the aid of the Launderometer or the Terg-O-Tometer . A new competi t ive de­vice was offered. New artificially-soiled fabrics tor study of cotton washing have been made available. One carries a soil more easily removed than some of the other artificially-soiled cottons and is suit­able for single wash tests. Another source offers a new full line of four products .

Research Fundamenta l research and development

applications continue. Sorption of mole­cules from detergent solutions by sohd surfaces being cleaned has been demon­strated quantitatively. Chernisorption has been shown to occur be tween sodium dodecyl sulfate and serum albumin, in which each of the 100 to 110 cationic groups in the albumin molecule holds a molecule of dodecyl sulfate. More d i a n this number of detergent molecules can be sorbed by the protein molecule, b u t the higher complexes dissociate dur ing elec­trophoresis.

These results further demonst ra te that the nature of the substrate is exceedingly important in the detergent process. As the field of detergency is explored further in terms of fundamental chemistry, the greater will be the possibilities in devel­opment of tailored syndets and surfactants, which have already been appl ied in nearly every industrial field, from t h e bake oven to the petroleum well.

T h e author expresses appreciat ion of editorial assistance and comments b y Cor­nelia T. Snell, John R. Skeen, and others.

Synthetic de tergent product ion was greatly a ided by the development of sulfur recovery from natura l gases containing hydrogen sulfide such as this converter a t Texas Gul f s sulfur recovery plant at Wor land , Wyo. , producing 300 long tons a day

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