Properties of soaps derived from distilled palm stearin and palm kernel fatty acids

Soaps made from blends of distilled palm stearin (PS) and palm (PK) kernel fatty acids were evaluated for total fatty matter, sodium chloride content, moisture content, hardness, Hunter whiteness, foamability, iodine value, titer value, and acid value. Data showed that these soaps had properties similar to palm-based soaps made from distilled palm oil and palm kernel fatty acids. The soaps showed good whiteness (greater than 80%) and foamability. Total fatty matter ranged from 10–18%, sodium chloride content was 0.5%, and free caustic was 0.1% except for blend 8 containing 10 PS:90 PK, which had a free caustic of 0.03%. Initial penetration value, a reflection of soap hardness, ranged from 32–126 mm, with an average value of 54 mm. This value is within the range of the best blends of palm-based soaps (50–63 mm). There was no obvious trend observed. Penetration value, however was found to stabilize after a month of storage with an average value of 19.4 mm. Soap with this hardness value is relatively hard and therefore should be blended with a small amount of soft oils.     

Chemical and physical characteristics of soap made from distilled fatty acids of palm oil and palm kernel oil

Manufacture of soaps from distilled fatty acids of palm oil (PO) and palm kernel oil (PK) is a well-established technology in Malaysia. Data on quality and characteristics of various blends of PO/PK fatty acid-based (palm-based) soaps made in Malaysia are not available, however. In view of this, the study described in this paper was undertaken. Eleven blends of palm-based bar soaps were made, and their properties were evaluated. There was an increase in the acid value of blended raw materials with increasing amounts of PK fatty acids. The iodine value and titer (°C) of blended raw materials, however, bear an inverse relationship with the amount of PK fatty acids. As expected, the hardness of the soap bars from the various blends increased with increasing PK fatty acid. Total fatty matter ranged from 76–85%, free caustic content was 0.1%, and sodium chloride content was 0.3–0.4%. Characteristics of soap blends made for this study were comparable with those from other countries. Quality of the soap obtained was comparable to those produced commercially.     

Glycerolysis of Soybean Oil with Crude Glycerol Containing Residual Alkaline Catalysts from Biodiesel Production

The glycerolysis reaction of soybean oil was evaluated using crude glycerol obtained from the transesterification of soybean oil with methanol, catalyzed by sodium methoxide and sodium hydroxide, without any purification step other than the methanol removal. Crude glycerol with the lower content of remaining inorganic catalyst produced the highest concentration of monoglycerides (about 42%). The effect of the addition of water on the glycerolysis reaction was analyzed, evidencing a low formation rate of products in the first stages of the reaction due to the transformation of the inorganic catalyst to soaps, which are weaker bases. The sample of crude glycerol that led to the best results was evaluated at several temperatures. It was observed that the reaction with crude glycerol exhibits a lower formation rate of monoglycerides at low temperatures (160 and 180 °C) compared with the reaction with pure glycerol and catalyzed with NaOH. This behavior was explained by the lower activity of the soaps present in the crude glycerol respect to the inorganic base. Above 200 °C the reaction is very fast and the monoglycerides formed are consumed to produce diglycerides.     

Thermal dehydrochlorination of PVC in the presence of rubber seed oil

Dehydrochlorination rates of PVC in nitrogen atmosphere were determined in the presence of rubber seed oil (RSO), epoxidized rubber seed oil (ERSO), barium soap of rubber seed oil fatty acids and barium soap of epoxidized fatty acid of rubber seed oil. The initial rates of dehydrochlorination and the time required for the degradation to attain 1% conversion showed that the rubber seed oil derivatives exert a stabilizing effect on the degradation of PVC. The order of the stabilizing effect was found to be metal soaps of ERSO < metal soaps of RSO < ERSO < RSO.     

Effects of superfatting agents on cracking phenomena in toilet soap

Palm stearin (POs) is one of the cheapest sources of C16–C18 fatty acids for use in soap making. Toilet-soap formulations containing a high content of POs, however, would result in hard soaps with a tendency to form cracks on the surface. This phenomenon can be overcome by addition of superfatting agents to increase plasticity of the finished product. In this study, two different blends of soap made from distilled POs, palm oil (PO), and palm kernel oil (PKO) fatty acids in the ratio of 40POs/40PO/20PKO and 70POs/30PKO were evaluated. The soaps were superfatted with glycerin, palm kernel olein, coconut oil, olive oil and canola oil. The levels of incorporation of each superfatting material were 1, 2, 4, and 6%, respectively. The samples were subsequently tested for both wet and dry crackings using the Hewitt Soap Company methods (numbers 78 and 79, respectively). The superfatted soaps had a total fatty matter of 73–83% and an average moisture content of 10%. The penetration value which indicates hardness increased with increasing amount of superfatting agents. Foaming or lathering property was good with the exception of the formulation using palm kernel olein and canola oil as superfatting agents. At all the above levels of superfatting agents added, no cracks were observed during both wet and dry cracking tests. A sample of soap superfatted with 2% canola oil, however, developed cracks during the wet cracking test. This resulted in a test score of 7. Superfatting soaps with 1–2% neutral oils or glycerin resulted in better quality soaps that were free of cracks.     

The separation of solid fatty acids from liquid fatty acids by the formation of acid soaps. I. Tallow soaps

The formation of acid soaps has been used successfully for the separation of a mixture of fatty acids into high and low iodine value fractions. The acid soaps of saturated acid can be made to crystallize from water leaving their unsaturated counter parts in solution. Acid soaps of saturated fatty acids are well characterized compounds with the formula R-COOM.R-COOH, where R is a straight alkyl chain, and M is sodium, potassium or ammonium. Optimum crystallization conditions involve a soap concentration of 2–5%, pH adjustment to between 7.0 and 8.0, an initial crystallization temperature not below 25C, and a crystallization period of at least 4 hr during which time cooling to a final temperature of 5–10C must be gradual, and agitation gentle.     

Chemical Properties and Fatty Acid Composition of Thunbergia fragrans Roxb. Seed Oil

The physicochemical and fatty acid compositions of seed oil extracted from Thunbergia fragrans were determined. The oil content, free fatty acids, peroxide value, saponification value and iodine value were 21.70 %, 2.25 % (as oleic acid), 9.6 (mequiv. O₂/kg), 191.71 (mg KOH/g) and 127.84 (g/100 g oil) respectively. The fatty acid profiles of the methyl esters showed the presence of 90.16 % unsaturated fatty acids and 9.84 % saturated fatty acids. Palmitoleic acid, which is usually found in marine foods and is unique in seed oils of botanical origin, was the major component (79.24 %). The oil can also be used in industries for the preparation of liquid soaps, shampoos and alkyd resin.     

Spectrophotometric determination of small proportions of polyunsaturated constituents in fatty materials

Summary Existing ultraviolet spectrophotometric methods have been modified for application primarily to the detection and estimation of low proportions of conjugated and nonconjugated unsaturated constituents in fats, oils, and soaps. The method is applicable also to fatty materials having high proportions of these constituents. Modifications include corrections for absorption by interfering substances, use of alkaline glycerol as an isomerization medium in the analytical procedure, and correction of absorption data on the isomerized product for absorption by conjugated constituents in the material before isomerization. The presence of small proportions of highly unsaturated conjugated and nonconjugated compounds is established in lards, tallows, tallow soaps, and highly purified esters and acids. Tall oil fatty acids are shown to contain approximately 10% of conjugated diene acids and a small amount of linolenic acid. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, United States Department of Agriculture.     

Variables Affecting the Production of Standard Biodiesel

Biodiesel is composed of fatty acid methyl esters, currently made from vegetable oils using basic catalysts. The oils must be reacted two or three times with methanol, in the presence of sodium methoxide to make products which meet the ASTM and European biodiesel standards. It is also believed that sodium hydroxide can never be used as the catalyst because it causes soap formation, which either lowers the yield or raises the acid number and makes product isolation difficult. Methods for producing standard biodiesel from low-acid-number soybean oil, in one chemical reaction using sodium hydroxide and a cosolvent, were recently reported. This study reports the effects of variables on the acid numbers and chemically bound glycerol contents of the products which led to the methods. These variables were the molar ratio of alcohol to oil, catalyst concentration, cosolvent volume, and reaction time. The alcohol-to-oil molar ratio must be at least 14, and the sodium hydroxide concentration should be at least 1.2 wt% (based on oil), to meet the necessary acid number and glycerol contents of the biodiesel. The volume of tetrahydrofuran cosolvent used must be 90–130% of that required to just create complete miscibility at the beginning of the reactions.     

Characterization of palm acid oil

Palm acid oil (PAO) is a by-product obtained from the alka-line refining of palm oil. It is used for making laundry soaps and for producing calcium soaps for animal feed formulations. The properties and composition of PAO may differ according to variations in the palm oil feedstock and the alkaline refining process. Because information on the characteristics of PAO is limited, this investigation aims to establish the properties of this product. Quality and oxidative parameters of 27 samples of PAO were determined. The six parameters analyzed were moisture and free fatty acid content, peroxide value, iodine value, saponification value and unsaponifiable matter. Headspace-gas-chromatographic (HSGC) analysis and gas-chromatographic analysis of the extract from Likens-Nickerson steam distillation of the samples were also carried out. Mean moisture content was 0.98%, free fatty acids 62.6% (palmitic acid), peroxide value 4.1 meq/kg, iodine value 50.2, saponification value 186 and unsaponifiable matter 0.53 HSGC profiles of a few samples showed the presence of one to three peaks, while the steam distillation extract showed the presence of aldehydes, ketones, furans and acids.     

Polyol-Derived Alkoxide/Hydroxide Base Catalysts I. Production

A metal methoxide is more expensive than a metal hydroxide and dissolves in methanol releasing a methoxide ion without producing water. The methoxide ion has a higher reaction rate making it more preferred for industrial biodiesel production. This study describes the preparation of alkoxide catalysts from metal hydroxides and non-volatile, non-toxic polyols. Heating aqueous solutions of metal hydroxides and different polyols (1,2-propanediol, 1,3-propanediol, glycerol, xylitol and sorbitol) under vacuum yielded polyol-derived alkoxide base catalysts (PDABC). Comparison of the drying process for respective sodium hydroxide-polyol combinations at two mole ratios of sodium hydroxide to polyol showed that drying at 2:1 mole ratio (metal hydroxide to polyol) was more efficient than that of 3:1. Dehydration of alkaline solutions containing three or more hydroxyl groups (glycerol, sorbitol and xylitol) was faster than drying similar solutions of diols. The empirical formula determined confirmed that the resulting powders contained mono-sodium substituted alkoxides at 1:1, 2:1 and 3:1 (sodium hydroxide: polyol) mole ratio. Fatty acid methyl esters were prepared from canola oil and methanol using glycerol sodium alkylate as a catalyst. The conversion yield of oil to methyl ester was greater than 99 %.     

A new method for free fatty acid reduction in frying oil using silicate films produced from rice hull ash

Sodium silicate films were produced from rice hull ash silica, and their application in reducing free fatty acid (FFA) in frying oil was investigated. Sodium hydroxide concentration of these films was 32, 28, 24, and 20% with silica concentration of 45, 50, 55, and 60%, respectively. Moisture contents of these films were 20–23%. Adsorption performance of the films was investigated in frying oil at 80°C for 10–40 min. FFA content gradually decreased with treatment time for all films. There were no significant differences in FFA content among films for treatments up to 30 min. Treatment with 45 and 50% silica films for 40 min led to significantly larger reduction in FFA compared to treatment with 60% silica film. Differences between the FFA content of oil treated for 40 min with 55% silica and the FFA content of oils treated with other silica films were insignificant. FFA content of oil decreased from 0.8 to 0.55, 0.55, 0.57, and 0.59% after 40 min treatment with 45, 50, 55, and 60% silica film, respectively. Peroxide values (PV) of treated oils slightly increased from 48 to about 60 meq/kg for films with 45, 50, and 55% silica. Treatment with 60% silica led to a decrease in PV values to 42 meq/kg. Soap content of oil increased from 51 to over 100 ppm as a result of silicate film treatment.     

Tall oil fatty acids

About 1949, with the advent of effective fractional distillation, the tall oil industry came of age, and tall oil fatty acids (TOFA), generally any product containing 90% or more fatty acids and 10% or less of rosin, have grown in annual volume ever since, until they amount to 398.8 million pounds annual production in the U.S. in 1978. Crude tall oil is a byproduct of the Kraft process for producing wood pulp from pine wood. Crude tall oil is about 50% fatty acids and 40% rosin acids, the remainder unsaps and residues; actually, a national average recovery of about 1–2% of tall oil is obtained from wood. On a pulp basis, each ton of pulp affords 140–220 pounds black liquor soaps, which yields 70–110 pounds crude tall oil, yielding 30–50 pounds of TOFA. Separative and upgrading technology involves: (a) recovery of the tall oil; (b) acid refining; (c) fractionation of tall oil; and occasionally (d) conversion to derivatives. TOFA of good quality and color of Gardner 2 corresponds to above 97% fatty acids with the composition of 1.6% palmitic & stearic acid, 49.3% oleic acid, 45.1% linoleic acid, 1.1% miscellaneous acids, 1.2% rosin acids, and 1.7% unsaponifiables.     

Preparation of sucrose esters by interesterification

Reactions between sucrose and esters of long chain fatty acids customarily have been conducted in a mutual solvent, such as dimethylformamide. The solvent-free interesterification of molten sucrose and fatty acid esters at temperatures between 170–187 C has now been performed with the aid of lithium, sodium and potassium soaps as catalysts and solubilizers. When the reactants were heated rapidly and then subjected to reduced pressure, the interesterifications could be brought to equilibrium in 12 min or less, including the time necessary to melt the sucrose. The several soaps and combinations of soaps employed differed markedly in their performance. No sucrose esters were obtained with lithium palmitate, while the yield with lithium oleate was among the best, but consisted of over 90% tetra- and higher esters of sucrose. Lower esters were best produced with combinations of lithium oleate with sodium or potassium oleate employed at a level of about 25% total soaps, based on the weight of sucrose. The type of fatty acid ester employed also markedly affected the yield of sucrose esters. Among the esters tested, methyl carbitol palmitate (which could be formed in situ), monopalmitin, distearin and technical grade diglycerides (48% diglycerides) prepared from completely hydrogenated cottonseed oil, interesterified readily. Presented at the AOCS Meeting, Minneapolis, October 1969. So. Utiliz. Res. Dev. Div., ARS, USDA.     

The decomposition of secondary esters of castor oil with fatty acids

In this study, thermal splitting of secondary fatty acid esters of castor oil was investigated to determine the reaction kinetics under various conditions. Zinc oxide,p toluenesulfonic acid and sulfuric acid were used as catalysts. Reactions were carried out at 260, 270, and 280°C. Experimental data fitted the first-order rate equation for the catalyzed and noncatalyzed reactions. In addition to the kinetic investigation, the splitting (pyrolysis) mixture was evaluated in the preparation of a synthetic drying oil. For this purpose, the mixed fatty acids of linseed, sunflower andEcballium elaterium seed oils were used in the esterification stage of the process. Pyrolysis mixtures were converted to drying oils by combining the liberated acids with equivalent amounts of glycerol. The oils thus obtained show good drying oil properties.     

Enhanced oil recovery using carboxylate surfactant systems

Oil displacement tests in water wet Berea sandstone cores containing residual crude oil flooded with water have shown that high tertiary oil recoveries can be obtained using the sodium salts of readily available carboxylic acids. Using a 10% pore volume surfactant slug containing 3.0% sodium isostearate and 3.0% isopentyl alcohol followed by a polyacrylamide mobility buffer resulted in a 92% tertiary oil recovery, which compares well with recoveries using petroleum solfonates. Oil recoveries were highly dependent on pH and added base. Aliphatic C18 carboxylates gave higher recoveries at lower pH using sodium bicarbonate as the added base (pH 8.5) rather than sodium hydroxide, sodium carbonate or sodium orthosilicate (pH 11–13). In contrast, aromatic carboxylates e.g., sodium p-(1-pentylnonyl)benzoate, gave higher recoveries at higher pH using sodium carbonate rather than sodium bicarbonate. Carboxylates with branched alkyl groups, e.g., isostearate, gave higher tertiary oil recoveries than unbranched carboxylates, e.g., oleate or stearate. Low cost tall oils and tall-oil fatty acids, when neutralized with base, gave oil recoveries of 60–80%. Carboxylates were found to give good oil recoveries even when significant amounts of calcium ion were present.     

The influence of NaOH on the stability of paraffinic crude oil emulsion

The alkaline–surfactant–polymer flooding using sodium hydroxide as the alkali component to enhance oil recovery at the on shore oil fields at Daqing in China has brought new problems for the oil industry. Even though, the reservoir contained paraffinic crude oil, the alkali added formed stable water-in-crude oil emulsion and de-emulsification process was necessary to separate oil and water.The problems related in the enhanced oil recovery process using the alkaline–surfactant–polymer flooding technique in the Daqing oil field have been investigated in the laboratory using fractions of Daqing crude oil. The oil was separated into asphaltene and aliphatic fractions and then used in an additive free jet oil to form model oils. The emulsion stability of each of the water-in-model oil emulsions formed between water or 0.6% sodium hydroxide solution and model oil was investigated. The interfacial properties such as interfacial tension and interfacial pressure of the systems were also measured. These in combination with the chemical nature of the fractions were used to get insight into the problem related to the ASP flooding technique using sodium hydroxide as the alkaline component.The study reveals that the sodium hydroxide solution reacts with fatty acids in the aliphatic fraction of the crude oil and/or with the fatty acids formed from the slow oxidation of long chain hydrocarbons, and form soap like interfacially active components. These accumulate at the crude oil–water interface and contribute to the stability of the oil/water emulsion.     

Fourier-transform infrared spectra of fatty acid salts—Kinetics of high-oleic sunflower oil saponification

Sodium, lithium, and calcium soaps obtained by saponification of high-oleic sunflower oil were studied by Fourier-transform infrared spectroscopy. Spectra of crude mixtures containing soap, glycerin, residual alkali, and triacylglycerols were compared to those of pure soaps obtained from fatty acids. The infrared spectra of crude soaps showed the same characteristic bands as pure ones. The absorption bands of asymmetric (ω₂) and symmetric (ω₁) stretching vibrations of the carboxylate group indicated that the metal-oxygen bonds of these soaps had an ionic character whose strength differed from one cationic counterion to another. Once the characteristic absorption bands of the soaps were assigned, a kinetics study of saponification was performed. Saponification by sodium, anhydrous lithium, and calcium hydroxides was an autocatalytic reaction, characterized by an S-shaped kinetics curve, whereas saponification by aqueous lithium hydroxide was stoichiometric. The structure of the metal-oxygen bond played a role in the kinetic mechanisms.     

The solubility of sodium and potassium soaps and the phase diagrams of aqueous potassium soaps

Summary Solubility data are provided and collected for the pure sodium and potassium soaps. Hydrolysis obscures the temperatures of solution but is obviated by the presence of a small excess of alkali. Each sodium soap has a large range of temperature between fair and high solubility, whereas the potassium soaps go abruptly into solution, at almost the same temperature and concentration of each soap. The only soaps that are even moderately soluble at room temperature are potassium laurate, myristate, and oleate, the potassium salt of acids from coconut oil, and the sodium oleate. The other sodium and potassium soaps of the saturated fatty acids require elevated temperatures for solution. Phase diagrams for the five commonest potassium soaps are developed and recorded. This work was the basis of a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, Stanford University, 1947.     

Essential fatty acid contents of various fats: Interpretations of values by physico-chemical tests

Biological assays of oil and fat products, free from isomers of the naturally-occurringcis-9,cis-12 linoleic acid, have been shown to provide estimates of essential fatty acid content which agree well with values obtained by spectrophoto-metric analysis. However, when partially hydrogenated fats, such as those used in margarines, are bio-assayed the estimates obtained are only about 60% of those derived by spectro-photometric tests. In a blended corn oil margarine, good agreement was obtained for linoleic acid content by using biological assay or spectrophotometry, thio-cyanometric procedure, column chromatography for saturates plus iodine value, and gas liquid partition (GLP) chromatography. This margarine fat contained about 29% of the essential form of linoleic acid, and had a ratio to saturated fatty acids of 1.6:1. The hydrogenated corn oil margarine is unlike conventional margarines in providing high amounts of the isomeric forms of linoleic acid which lack essential fatty acid activity. For this reason, poor agreement was obtained between biological assay results and those by physico-chemical measurements of linoleic acid content. Such fat contains only about 6% of the essential form of linoleic acid, with a ratio to saturated fatty acids of ca. 0.3.1. From this study it is now possible to characterize, even without bio-assay data, the fatty acid composition of a highly isomerized fat, such as is found in hydrogenated corn oil margarine. The characterization groups the fatty acids into saturates and total linoleic acids, with the latter including estimates of the positional isomers of linoleic acid with widely spaced double bonds,trans forms of linoleic acid with methylene-in-terrupted double bonds, linoleic acids with the double bonds in conjugated position, andcis-9,cis-12 linoleic acid. The combined use of the spectrophotometric and thiocyanometric procedures makes it possible to estimate the essential fatty acid content of hydrogenated fats containing residual dienes.