production of ethoxylated fatty acids derived from

255

Journal of Oleo ScienceCopyright ©2012 by Japan Oil Chemists’ SocietyJ. Oleo Sci. 61, (5) 255-266 (2012)

Production of Ethoxylated Fatty Acids Derived From Jatropha Non-Edible Oil As a Nonionic Fat-Liquoring AgentY. El-Shattory1＊ , Ghada A. Abo-ELwafa1, Saadia M. Aly1 and EL -Shahat H. A. Nashy2

1 Fats and Oils Department, National Research Centre, Dokki, Cairo, Egypt.2 Department of Chemistry of Tanning Materials and Leather Technology, National Research Centre, Dokki, Cairo, Egypt.

1 INTRODUCTIONRecently, the world is directed to nature in all aspects of

life in order to reduce environmental pollution and health hazards combined with synthetic materials and at the same time save different energy sources. From this point of view, natural fatty derivatives（oleochemicals）have been used as intermediate materials in several industries replacing the harmful and expensive petrochemicals.

Fatty ethoxylates are one of these fatty derivatives in which a fatty acid or fatty alcohol is used as the natural precursor in ethoxylates preparation. Ethylene oxide-based nonionic surfactants are compounds that contain a poly（ethylene oxide）chain as a hydrophile1）. Ethoxylated fatty acid esters are well known as ether-ester-type non-ionic surfactants with numerous applications. For example, ethoxylated stearyl stearates are used as emulsifi ers, dis-persants or oil phase adjusters in cosmetics or in industrial

＊Correspondence to: Y. El-Shattory, Fats and Oils Department, National Research Centre, Dokki, Cairo, Egypt.E-mail: [email protected] November 18, 2011 (recieved for review May 17, 2011)Journal of Oleo Science ISSN 1345-8957 print / ISSN 1347-3352 onlinehttp://www.jstage.jst.go.jp/browse/jos/　　http://mc.manusriptcentral.com/jjocs

products2）. Also ethoxylated methyl laureates have been studied as wetting agents3）.

Fatty acid ethoxylates and alcohol ethoxylates can be readily obtained by the direct reaction of fatty acids or fatty alcohols that have an active hydrogen in their mole-cules with ethylene oxide in the presence of an alkaline（e.g. sodium hydroxide）or an acidic catalyst（e.g. antimony pentachloride）4）. Overused edible oils were ethoxylated using potassium hydroxide catalyst at 180℃ for 20 h5）. Ethylene oxide, however, cannot directly react with fatty methyl esters that have no active hydrogen by using those catalysts6）.

Nowadays, Jatropha tree has been successfully cultivat-ed in Egypt as it can grow well in the desert as it withstand drought and can be irrigated with treated sewage water since its oil is non-edible. Jatropha seeds contain about 27-40％ non edible viscous oil which can be used for

Abstract: Natural fatty derivatives (oleochemicals) have been used as intermediate materials in several industries replacing the harmful and expensive petrochemicals. Fatty ethoxylates are one of these natural fatty derivatives. In the present work Jatropha fatty acids were derived from the non edible Jatropha oil and used as the fat source precursor. The ethoxylation process was carried out on the derived fatty acids using a conventional cheap catalyst (K2CO3) in order to obtain economically and naturally valuable non-ionic surfactants. Ethoxylation reaction was proceeded using ethylene oxide gas in the presence of 1 or 2% K2CO3 catalyst at 120 and 145°C for 5, 8 and 12 hours. The prepared products were evaluated for their chemical and physical properties as well as its application as nonionic fat-liquoring agents in leather industry. The obtained results showed that the number of ethylene oxide groups introduced in the fatty acids as well as their EO% increased as the temperature and time of the reaction increased. The highest ethoxylation number was obtained at 145°C for 8 hr. Also, the prepared ethoxylated products were found to be effective fat-liquors with high HLB values giving stable oil in water emulsions. The fat-liquored leather led to an improvement in its mechanical properties such as tensile strength and elongation at break. In addition, a significant enhancement in the texture of the treated leather by the prepared fat-liquors as indicated from the scanning electron microscope (SEM) images was observed.

Key words: Jatropha Fatty Acids, Fat-liquor, Ethylene Oxide Gas, Chrome Tanned Leather, Ethoxylated Fatty Acids, Mechanical Properties, Scanning Electron Microscope.

Y. El-Shattory, Ghada A. Abo-ELwafa, Saadia M. Aly et al.

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biodiesel production, manufacture of candles and soap, in cosmetics industry, paraffin substitute or extender and other industial applications. So, this work explores another usage of the non edible Jatropha fatty acids as a fat-liquor-ing agent in order to save the needed edible fats and oils for food purposes.

Leather is a tanned animal hide or skin. Leather industry involves the removal of a great part of hide substances like hair, soluble proteins, epidermis, fat, and fl esh by mechani-cal and chemical processes. Tanning is a durable preserva-tion of perishable biological material, this means that, the purpose of tanning is to bring irreversible stabilization of native proteins that is prone to putrefaction and increase its resistance to enzymatic degradation and chemicals. Chrome tanned is the most important and common tanning agents, which used for the production of all types of leather7, 8）. But chrome tanned leather when dries out, cohesion of the fi bers take place resulting to hard intractable leather which is quite diffi cult to re-hydrate9）. This means that, chrome tanned leather when dries out, it will become bony, hard and thus will be unsuitable for use in most purposes, besides its color turns darker and becomes less appealing.

Therefore, fat-liquoring process is an essential operation by which an introduction of a fatty matter into the leather fi bers takes place. Incorporation of fat-liquor into leather reduces the damaging effect of air oxidation and control the differential shrinkage of grain versus corium of the leather during drying process. Therefore, introducing a lu-bricant into the leather keeps the fi bers apart during drying and reduces frictional forces within the fi ber weaves thus allowing the fi bers to move laterally over each other. Also, it gains the leather grains specifi c properties which make it suitable for its most effective utilization10）. In addition to above fat-liquor helps to prevent the loosening of the leather grain and intended to lubricate the tanned leather fi bers to obtain leather of full and soft handle, abrasion re-sistance, fl exibility, pliability and stretching as well as im-proving its mechanical properties11）.

The aim of this work is to utilize non-edible vegetable oil newly cultivated in Egypt like Jatropha oil in the prepara-tion of ethoxylated fatty acids to be used as nonionic sur-factants. On this base, the derived Jatropha fatty acids were used for the preparation of ethoxylated nonionic sur-factant under different reaction conditions and the prod-ucts were applied as leather fat-liquors in order to replace the usage of industrial one with a safe to environment, ef-fective and healthy natural intermediate. The emulsion sta-bility of the prepared nonionic fat-liquors was evaluated as well as their application in leather fat-liquoring. Also, the investigation of the resulting fat-liquored chrome tanned leather was taken into consideration.

2 EXPERIMENTAL2.1 Materials

2.1.1 Jatropha oil was extracted from Jatropha curcas seeds which were cultivated in southern parts of Egypt using commercial n-hexane.

2.1.2 Oil was saponified using potassium hydroxide and free fatty acids were obtained by precipitating the salt using HCL and extracted using light petroleum ether.

2.1.3 Ethylene oxide gas cylinder was purchased from Eti-co Gas Company for gases（EL-Sharqia for gases, 10th of Rmadan Industrial City）.

2.1.4 Potassium carbonate catalyst and all solvents and chemicals used were of highly pure grade purchased from Merck.

2.2 Methods

2.2.1 Determination of fatty acid composition:Fatty acid composition was determined for the separated

Jatropha fatty acids as follows:2.2.1.1 Preparation of fatty acid methyl esters:

About 0.2 gm of Jatropha fatty acids was mixed with 30 ml sulfuric acid : methanol（4 : 96 v/v）in a 250 ml round bottom fl ask. The contents were then heated under refl ux for about three hours. The methyl esters were thrice ex-tracted with petroleum ether（40-60℃）then it was washed several times with distilled water till the washings were neutral to phenol phthalein indicator. The combined fatty acids methyl esters layers were dried over anhydrous sodium sulfate and fi ltered. The petroleum ether was then removed using a rotary evaporator and aliquots of the fatty acid methyl esters were analyzed by gas chromatogra-phy12）.2.2.1.2 Gas-liquid chromatographic analysis of fatty acids

methyl esters:The identification of the components of fatty acids

methyl esters was done using gas liquid chromatography on a Hewlett Packard Model 6890 chromatograph equipped under the following conditions:

- Separation was done on an INNO wax（polyethylene glycol）Model No. 19095 N-123, 240℃ maximum, capil-lary column 30.0 m×530 μm×1.0 μm, nominal fl ow 15 ml/min. with average velocity 89 cm/sec. and pressure 8.2 psi.

- Column temperature was 240℃ with temperature pro-gramming: Initial temperature 100℃ to 240℃ maximum with 10℃ rising for each minute and then hold at 240℃ for ten minutes.

- Injection temperature 280℃, back inlet, with split ratio 8:1, split fl ow 120 ml/min., gas saver 20 ml/min.

-Carrier gas was nitrogen with fl ow rate 15 ml/min.-Flame ionization detector temperature 280℃.-Hydrogen fl ow rate 30 ml/min.-Air fl ow rate 300 ml/min.

Production of Ethoxylated Fatty Acids Derived From Jatropha Non-Edible Oil As a Nonionic Fat-Liquoring Agent

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2.2.2 Ethoxylation reactionThe reaction of fatty acids with ethylene oxide was

carried out in the closed system shown in Fig. 1 according to Wrigley et. al.13）. Jatropha fatty acids（5 gm）and 1％（or 2％）potassium carbonate（K2CO3）as catalyst were mixed in the round flask of the system. The reaction mixture was stirred using a magnetic stirrer and heated under nitrogen atmosphere to the desired reaction temperature（120 and 145℃）.

The gentle fl ow of nitrogen was then halted and the ni-trogen was replaced by ethylene oxide which was thereaf-ter kept in harmony with the rate of the reaction. The fl ow of ethylene oxide was stopped and replaced by nitrogen to cool the reaction mixture after the required period of time（5, 8, 12 h）. The weight difference of the ethoxylation system before and after the reaction was recorded. 2.2.3 Evaluation of the ethoxylated Jatropha fatty acids

The prepared ethoxylated samples were then evaluated by the following analysis:2.2.3.1 Chemical Characteristics 2.2.3.1.1 Determination of iodine value（I.V.）, acid value

（A.V.）and saponifi cation value（S.V.）:They were carried out according to AOCS Official

Methods Cd 3d-63, Cc 18-80 and Tl 1a-6414）respectively.2.2.3.2 Physical characteristics 2.2.3.2.1 Determination of the solubility of ethoxylated

samples in different solvents:The solubility of ethoxylated samples was determined in

water, oil, ethanol, n-hexane and diethyl ether at room temperature and at 75℃ or at the boiling point of the solvent13）.2.2.3.2.2 Melting point determination

The melting point of the ethoxylated samples was re-corded using electro thermal IA 9100 digital melting point apparatus.

2.2.3.3 FT-IR AnalysisThe change in the functional groups of fatty acids before

and after ethoxylation was studied using FT-IR analysis. All control and ethoxylated samples were subjected to FT-IR analysis on a Nexus 670 Fourier Transform Infra Red spec-trometer, Thermo Nicolet, USA. The FT-IR spectra were analyzed using “Omnic 5.2a” software. A fixed sample volume（5μl）of each sample was carefully and homoge-neously spread between two KBr disks of fixed weights. The samples were referenced to their own blank KBr disks. For collection of the data, a DTGS detector and KBr beam-splitter were used. 2.2.3.4 Quantitative determination of the ethoxylated

products The ethoxylated products were quantitatively deter-

mined through: 2.2.3.4.1 Molecular weight determination using Gel Perme-

ation Chromatograph（GPC）The average molecular weight of Jatropha fatty acids

before and after ethoxylation were determined using gel permeation chromatograph（GPC）coupled with RI detector. Samples were dissolved in tetrahydrofuran and the GPC instrument used in the measurements was a modified HPLC, Waters 600 System Controller, 717 plus Autosam-pler. Columns: Phenomenex Phenogel 10 um 500 A, 250×8 mm Phenomenex Phenogel 5 um 50 A, 300×7.8 mm. De-tection: Waters model 2410 Refractive index, ATTN＝16x. Eluent: dimethylformamide DMF（100％ by vol）. Flow rate: 0.7 ml/min. Temperature: 50℃. Injection volume: 25ul. 2.2.3.4.2 Degree of Ethoxylation

The degree of ethoxylation was calculated depending on the determination of the introduced number of ethylene oxide as follows:

1） The number of ethylene oxide（n）moles introduced in the fatty acids was estimated depending on the molec-ular weight difference of the sample before and after ethoxylation.

2） The degree of ethoxylation was calculated by dividing the molecular weight of the group’s number of ethyl-ene oxide added by the total molecular weight of the ethoxylated sample multiplied by 100, equation 1.

EO％＝ nx44R＋（nx44）×100 （1）

Where n＝Number of ethylene oxide moles.44＝Molecular weight of one mole ethylene oxide.R＝ Molecular weight of the hydrophobe（fatty acid frac-

tion）.2.2.3.5 Hydrophile-Lipophile Balance（HLB）

Hydrophile-lipophile balance of the nonionic fat-liquors was calculated based on equation（2）15）.

HLB＝EO ％5

（2）

Where EO％: is the percent of introduced ethylene oxide Fig. 1　 Apparatus used for the reaction with ethylene oxide.


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2.2.4 Fat-Liquoring ProcessThe leather samples were worked up in wet-finishing

process as follow:The leather pieces were first washed with water for

about 15 minutes and drained water off. Then neutraliza-tion process was carried out using 1％ sodium formate and running the drum at ≈ 10 rpm for 15 minutes at ambient temperature. Thereafter, 0.5％ sodium bicarbonate was added and the drum was run for additional 10 min at the same speed. The leather pieces gave a greenish blue color with bromo cresol green throughout the whole thickness（pH 5.0-5.3）. The neutralized leather pieces were retanned and dyed with 5％ acid dye for 30 minutes. Then, the fat-emulsion was added to the dyeing bath at room tempera-ture. After complete addition of the fat liquor, the drum was run at ≈ 10 rpm for 40 minutes at 30℃. The leather pieces were washed with water for about 10 minutes, removed from the drum, sammed and left to dry in air through hanging up at room temperature. The dried leather pieces were used for the various physical proper-ties investigations.

- All percentages and chemical additives doses were cal-culated on the basis of leather weight（w/w）.

2.2.5 Mechanical MeasurementsDumbbell shaped specimens 50 mm length and 4 mm

（neck width）were used for measurements of mechanical properties（tensile strength and elongation at break）. The measured data are the average of four transverse and lon-gitudinal measurements for each sample. These tests were carried out using an Instron Machine（model 1195）16）. The cross-head speed was controlled at 50 mm/min and the tests were done at room temperature（25℃）. 2.2.6 Scanning Electron Microscope

Specimens of experimental and control were prepared as circular samples（10 mm）and then subjected to sputter coating of gold ions to prepare a conducting medium（sputter coater-Edwards-Model S-150 A, Eng）. A Jeol scanning microscope（Japan）JSM-T20 was used for the mi-croscopic study.

3 RESULTS AND DISCUSSION3.1 Fatty acid composition

Table 1 shows fatty acid composition of Jatropha fatty acids. Fatty acids content can be divided into two main groups as illustrated in Table 1.

It can be seen that, the saturated fatty acids content of Jatropha fatty acid was（19.18％）while unsaturated fatty acids content was（81.21％）. Also, it was noticed that, the ratio of total saturated fatty acids to the total unsaturated fatty acids（1: 4.23）. Oleic acid constitutes more than 61％ of the total unsaturated fatty acids, while linoleic acid had much higher value（34％）than linolenic（2％）of the total unsaturated fatty acids. On the other hand, palmitic acid showed more than 83％ of the saturated fatty acids and 15％ of the total fatty acids.

3.2 Ethoxylation Reaction

The ethoxylation reaction had failed when it was carried out directly on Jatropha oil at different temperatures（80-180℃）and different percentages of K2CO3 catalyst. This can be attributed to the triglyceridic composition（esters）of Jatropha oil which cannot be ethoxylated using conventional catalysts like K2CO3 due to lack of the active hydrogen necessary to initiate such reaction using these catalysts1）. Therefore, free fatty acids were separated from the oil to enhance the reaction using the cheap and avail-able catalyst K2CO3 as illustrated in Scheme 1.

This reaction would lead only to the formation of mono-esters17）which means that the reaction with ethylene oxide would be preferred towards esterifi cation reaction.

It is worthy mentioned here that, when the reaction was carried out at 80-120℃ using 1％ K2CO3 no product was obtained. But, ethoxylated product was obtained at 145℃ using 1％ K2CO3 and/or at 120℃ using 2％ K2CO3.

3.3 Evaluation of the ethoxylated Jatropha fatty acids

3.3.1 Chemical CharacteristicsTable 2 shows the chemical characteristics of the ethox-

ylated Jatropha fatty acids at 145℃ using 1％ K2CO3 for different periods of time.

It is clear from Table 2 that ethoxylation reaction caused a large decrease in acid value due to a large consumption of the fatty acids as ethoxylation reaction mainly happens with the free carboxylic groups. Also, a large decrease in

Table 1　Fatty acid composition of Jatropha fatty acids.

Fatty acids, %

Saturated Unsaturated

Fatty acids of Jatropha

oil

C14

Myristic acid

C16

Palmitic acid

C20

Arachidic acid

C22

Behenic acid

TotalC16:1

Palmitoleic acid

C18:1

Oleic acid

C18:2

Linoleic acid

C18:3

Linolenic acid

Total

Percents, % 0.93 15.93 1.41 0.91 19.18 1.21 50.20 28.18 1.62 81.21


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iodine value was observed which indicates a relative reduc-tion in the magnitude of the unsaturated moiety to the mo-lecular weight of the product after ethoxylation reaction.

In addition to a large decrease in saponification value due to the blockage of the saponifi able carboxylic groups of the fatty acids during the ethoxylation reaction. As the temperature and time of the ethoxylation reaction in-creased the acid, iodine and saponification values were found to decrease.

Table 3 represents the chemical characteristics of the ethoxylated fatty acids prepared at120℃. It is clear from Table 3 that ethoxylating Jatropha fatty acids at 120℃ was carried out using 2％ K2CO3 because 1％ did not facilitate the reaction.

Also, it could be noticed from Table 3 that no-product

obtained after 5 h, while the reaction started after 8 hours. This is might be due to that during the early stage of fatty acid ethoxylation there is a period of time where negligible amounts of product are formed which is called the induc-tion period. After this initial period, reaction rate increases. Therefore, the reaction was started after fi ve hours when it was carried out at 145℃ and in the 8th hour at 120℃ which agreed with results obtained by O'Lenick and Par-kinson18）. Acid, iodine and saponifi cation values were also found to decrease during the reaction at 120℃.3.3.2 Physical Characteristics 3.3.2.1 Melting point

The appearance of the samples differed before and after the reaction. It was observed practically that as the tem-perature and time of the reaction increased the liquid fatty

Scheme 1　The reaction of ethylene oxide with fatty acids using alkaline catalyst.

Table 2　 Chemical Characteristics of Jatropha fatty acids ethoxylated at145℃ using 1% K2CO3 as a catalyst for different periods of time.

Time of reaction (hours)

Acid value (mg KOH/g)

Iodine value (g/100g)

Saponifi cation Value

(mg KOH/g)

0* 194.01 111.42 190.46

5 0.35 29.76 52.36

8 0.22 16.31 18.22

12 0.30 10.95 17.33

・Control sample (non ethoxylated Jatropha fatty acids).


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Table 3　 Chemical Characteristics of Jatropha fatty acids ethoxylated at120℃ using 2% K2CO3 for different periods of time.


Acid value (mg KOH/g)

Iodine value (g/100g)

Saponifi cation Value

(mg KOH/g)

0* 194.01 111.42 190.46

5 No product No product No product

8 0.24 72.30 138.88

12 0.22 14.62 36.64

・Control sample (non ethoxylated Jatropha fatty acids).

Table 4　 Melting point versus iodine value of Jatro-pha fatty acids ethoxylated at145℃ using 1% K2CO3 for different periods of time.


Melting point of Ethoxylated Jatropha F.A.

(℃)

Iodine value(g/100g)

5 31.9 29.76

8 52.7 16.31

12 57.2 10.95

Table 5　 Melting point of Jatropha fatty acids ethox-ylated at120℃ using 2% K2CO3 for differ-ent periods of time.


Melting point of Ethoxylated Jatropha F.A.

(℃)

Iodine value(g/100g)

8 liquid 72.30

12 44.0 14.62

Table 6　 Solubility of ethoxylated Jatropha fatty acids at 120 and 145℃ for dif-ferent periods of time.

Solvent Temp.

Solubility in different solvents at different temperatures

Ethoxylated Jatropha fatty acids

at 120℃ at 145℃

Water

5 hr 8 hr 12 hr 5 hr 8 hr 12hr

Room Temp. － SS S S PS S

75℃ － SS S S S S

－

Vegetable Oil

Room Temp. － S PS PS PS PS

75℃ － S S S S S

－

Ethanol

Room Temp. － S S S S PS

75℃ － S S S S S

－

Diethylether

Room Temp. － S SS S SS I

Boiling point － S S S PS I

－n -

hexane

Room Temp. － S SS PS SS I

Boiling point － S SS S PS I

Where: S＝soluble　PS＝Partially soluble　SS＝Sparingly soluble　I＝Insoluble


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acid at room temperature turned after ethoxylation to be solid at room temperature. Tables 4 and 5 show that the melting points of the ethoxylated fatty acids samples in-creased as the time and temperature of the reaction in-creased. This can be attributed to the relative decrease in the magnitude of unsaturation moiety related to the product molecular weight during the reaction.3.3.2.2 Solubility in different solvents:

Table 6 shows that, almost all of the ethoxylated Jatro-pha fatty acids samples prepared at 145℃ were soluble in water either at room temperature or at 75℃. Ethoxylated Jatropha fatty acids prepared at 120℃ for 12hr was found to be soluble in water. All of the prepared samples were soluble in warm vegetable oil and warm ethanol. As the temperature and time of ethoxylation reaction increased the solubility of the samples in diethyl ether or n-hexane decreased.3.3.3 FT-IR Analysis

Figure 2 shows an FT-IR chart of polyethoxylated oleic acid（9 mol ethylene oxide）as a reference spectrum19）.

The FT-IR spectra of Jatropha fatty acids before and after ethoxylation were shown in Figs. 3-8. The spectra comparison revealed that, a broad characteristic absorption band appeared at about 3430 cm－1 for O-H stretching vi-bration intermolecular hydrogen bonded due to the ethox-ylated product. This band was found to be more broad and strong at 145℃ for 8hr, at 145℃ for 12hr and at 120℃ for 12hr. The absorption band at ～3005 cm－1 representing the unsaturation moiety in the fatty acid sample disap-peared after ethoxylation. Two bands at positions ～2925 and ～2855 cm－1（C-H stretching）in samples before ethox-ylation（Fig. 3）became sharper after ethoxylation this may be due to the increase in the number of CH2 groups. A band at ～1177 cm－1 appeared after ethoxylation which represents C-O-C group.

Generally, the bands were more strong and detectable for samples prepared at 145℃ than those prepared at 120℃. The previously mentioned ethoxylated family bands were agreed with that recorded by Fiveash Data Manage-ment19）and by Ovalles et al.20）.

3.3.4 Quantitative Determination of Ethoxylated products（Determining the number of introduced ethylene ox-ide moles）.

The number of ethylene oxide moles（n）was determined depending on the highest increase in weight of sample after ethoxylation as follows: 3.3.4.1 Weight difference determination

Table 7 illustrates the weight increase of the ethoxylated sample. Depending on the highest increase in weight（Table

Fig. 2　 FT-IR chart of polyethoxylated oleic acid (9 mole ethylene oxide). Fig. 3　FT-IR chart of Jatropha fatty acids

Fig. 4　 FT-IR chart of ethoxylated Jatropha fatty acids at 145℃ using 1% K2CO3 for 5 hours.



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7）, two ethoxylated samples were selected to be analysed for their molecular weight determination 3.3.4.2 GPC Molecular weight and quantitative determina-

tion The number and weight-average molecular weights（Mns,

Mws）of Jatropha fatty acids before and after ethoxylation are shown in Table 8.

As illustrated in Table 8, the molecular weight highly in-

creased after ethoxylation by more than three times than that of fatty acids, due to the introduction of high number of ethylene oxide molecules into the fatty acids. Further-more, it was noticed that the average molecular weight of ethoxylated Jatropha fatty acids increase as the reaction temperature increases. 3.3.4.3 Ethoxylation percent（EO％）and Hydrophile-lipo-

phile balance（HLB）The number of ethylene oxide moles and their percent

（EO％）introduced into ethoxylated Jatropha fatty acids as well as hydrophile-lipophile balance（HLB）were calculated based on the difference in molecular weight of Jatropha



Table 7　 Weight difference of Jatropha fatty acids before and after ethoxylation at 120 and 145℃ for different periods of time.

K2CO3

catalyst %Reaction

temperatureTime ofreaction

Increase in weight (gm)

2% 120℃5 hours 0.00

8 hours 2.75

12 hours 15.2

1% 145℃5 hours 13.80

8 hours 23.4

12 hours 23.5

Fig. 8　 FT-IR chart of ethoxylated Jatropha fatty acids at 120℃ using 2% K2CO3 for 12hours.

Table 8　Mn, Mw and PDI of ethoxylated Jatropha fatty acids.

Samples Mn , g/mol Mw , g/mol PDI(Mw/ Mn)

Jatropha fatty acids 4.0244×102 5.1871×102 1.2889×102

Ethoxylated Jatropha fatty acids at 120℃ for 12 hr using

2% K2CO3 catalyst1.4098×103 2.5812×103 1.8309×103

Ethoxylated Jatropha fatty acids at 145℃ for 8 hr using

1% K2CO3 catalyst2.3544×103 4.4202×103 1.8774×103

Where: Mn, number average of molecular weight, Mw, weight average of molecular weight, PDI, poly dispersity


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fatty acids before and after ethoxylation. The selected eth-oxylation conditions enhanced the introduction of a high number of ethylene oxide groups and consequently in-crease in EO％ as shown in（Table 9）.

The Hydrophile-lipophile balance（HLB）concept is one of the most important factors in the evaluation of a fat-li-quor emulsion. HLB is an expression of the relative simul-taneous attraction of a surfactant for water and/or for oil（or for the two phases）, this mean that HLB of a surfactant determines the emulsion type that tend to be formed21）. Akoh and Nwosu22）found that low value HLB of 3-6 will promote or stabilize W/O emulsions, while an intermediate values（8-13）will stabilize O/W emulsions, and high values such as（15-18）will act as a solubilizier15）.

If the fat-liquor is unstable, it cannot give a proper fat-li-quoring effect, due to the separation of fat from the emul-sion before it's fi xing to the leather fi ber. So that, it is nec-essary to evaluate the stabilization of prepared non-ionic fat-liquors emulsions through determining HLB value.

The prepared ethoxylated Jatropha fatty acids at 120℃ for 12 hr using 2％ K2CO3 catalyst have HLB value of 15.98 while it was found to be 17.65 for the sample ethoxylated at 145℃ for 8 hr using 1％ K2CO3 catalyst（Table 9）. This means that, they forms an “O/W” emulsion type, and simply dispersible in water. In other words a fineness of emulsion is formed since ethoxylated portions as well as non-ethoxylated portion of the ester, which is present in the fat-liquor, are emulsifi able. The obtained HLB indicated that the prepared ethoxylated Jatropha fatty acids can form a stable emulsion and transfer from the aqueous bath to the leather and penetrate into it, which means that they can be used as good fat-liquors.3.3.5 Mechanical Characters of fat-liquored leather

The mechanical properties were evaluated according to standard Egyptian physical testing method of leather（ES-123）23）, Table 10. Fat-liquoring process was carried

out on neutralized leather using 6％/100 g leather. Me-chanical properties include the measurement of the tensile strength and elongation at break, have been given in the greatest consideration on the evaluation of fat-liquored leather, because, it gives an indication of fi ber lubricity. It is obvious from Table 10 that tensile strength and elonga-tion at break of fat-liquored leather were improved than that of the un fat-liquored chrome tanned one. Also, it was noticed from Table 10 that, mechanical properties of leather treated by ethoxylated Jatropha fatty acids at 145℃ for 8 hr using 1％ K2CO3 catalyst as a fat-liquor was relatively higher than that of ethoxylated Jatropha fatty acids at 120℃ for 12 hr using 2％ K2CO3 catalyst. The en-hancement of mechanical properties is attributed to good lubrication of fi bers, as confi rmed by scanning electron mi-crograph, Figs. 9, 10.3.3.6 Scanning Electron Microscopy（SEM）

The most effi cient tool for the evaluation of fat-liquored leather is the Scanning Electron Micrograph（SEM）because it looks deeply into hide fiber structure, and shows the effect of fat-liquor on fiber and grain surface. It was ob-served from microscopically analyses（SEM）that, the treated leather by the prepared fat-liquors has a smooth fi bers and soft grain, and modifi ed handle because the pre-

Table 9　 Effect of ethoxylation on Jatropha fatty acids and their EO% and HLB values after ethoxylation.

Sample typeMolecular

weight

Moles number of ethylene oxide

introducedEO%* HLB*

Jatropha fatty acids 518.71 －－－Ethoxylated Jatropha fatty

acids at 120℃ for 12 hr using 2% K2CO3 catalyst

2581.2 46.88 79.9 15.98

Ethoxylated Jatropha fatty acids at 145℃ for 8hr using

1% K2CO3 catalyst4420.2 88.67 88.27 17.65

* EO% = (Difference in molecular weight / molecular weight of ethoxylated Jatropha fatty acids)*100

* HLB = EO%/5

Table 10　 Mechanical properties of leather treated with two ethoxylated Jatropha fatty acids fatliquors.

Tensile Strength, M. Pa

Strain at rupture, %

Chrome tanned leather 20.15 71.2

Fatliquored leather (1)120℃/12 hr 2% K2CO3

29.6 132.5

Fatliquored leather (2)145℃/ 8 hr 1% K2CO3

32.9 140.25


J. Oleo Sci. 61, (5) 255-266 (2012)

264

Fig. 9a　SEM of grain surface of chrome tanned leather.

Fig. 9b　 SEM of grain surface of chrome tanned leather fat-liquored by ethoxylated Jatropha fatty acids at 120℃ for 12 hr using 2% K2CO3catalyst.

Fig. 9c　 SEM of grain surface of chrome tanned Fat-liquored by ethoxylated Jatropha fatty acids at 145℃ for 8 hr using 1% K2CO3catalyst.

Fig. 10a　 SEM of fi ber bundles of chrome tanned leather.

Fig. 10b　 SEM of fi ber bundles of chrome tanned leath-er fat-liquored by ethoxylated Jatropha fatty acids at 120℃ for 12 hr using 2% K2CO3

catalyst.

Fig. 10c　 SEM of fiber bundles of chrome tanned leather fat-liquored by ethoxylated Jatropha fatty acids at 145℃ for 8 hr using 1% K2CO3 catalyst.


J. Oleo Sci. 61, (5) 255-266 (2012)

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pared fat-liquors protect the surface of the fibers with a thin film of lubricant resulting soft leather, Figs. 9, 10. Scanning electron microscope of the cross-section of the leather fi bers before（Fig. 10a）and after fat-liquoring（Fig. 10b & c）showed a signifi cant lubrication of fi ber bundles and surface grain of fi ne and loose texture.

In addition, the grain surface（x50）of the treated leather exhibits no cracking（fi rm grain）and no fat-spew, Fig. 9 b, c. This can be attributed to the low percentage of free fatty acids in the prepared fat-liquors, where, high free acid tends to cause spewing and leads the production of narsh and cracky leather. Also, the vivid shade of the fat-liquored leather was obtained i.e., the treated leather has a uniform shade. This is due to that the prepared fat-liquor has a lower iodine value, Tables 2 & 3. Iodine value has a great effect on color shade, where higher iodine value indicate that the fat-liquor will give yellow eventually when applied to white leathers due to light（UV. light）and temperature may breakdown the unsaturation moiety（neutral fat）into acids［23］, leading to fat-spews as well as possible fogging, resulting in yellowing and the production of bad odors. The yellowing of fat-liquors interferes especially with light shades.

CONCLUSIONSThe results of this work revealed that:-1． Ethoxylation reaction was carried out under different

conditions and the optimum conditions were found to be at 145℃/8hr,1％ K2CO3 & 120℃/ 12hr, 2％ K2CO3 with a high number of introduced ethylene oxide groups.

2． The prepared ethoxylated fat-liquors at 145℃/8hr, 1％ K2CO3 have superior properties of better penetration in the leather than at 120℃/ 12hr, 2％ K2CO3 due to its HLB value.

3． Tensile strength and elongation at break as well as texture of leather were markedly improved as the in-troduction of fat-liquors.

4． The prepared ethoxylated fat-liquors based on derived fatty acids has suitability to a far extent for fat-liquoring of chrome tanned leather.

5． Its recommended here that the Egyptian tanner can easily reach the fi gure required in the local specifi ca-tions for such type of leather.

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production of ethoxylated fatty acids derived from

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