A comparison of six solvents for the extraction of jojoba seed

Summary Data are presented which show the effects of different solvents on the yield and properties of liquid wax fromSimondsia chinensis (jojoba) and on the characteristics of the hydrogenated waxes obtained from the liquid waxes. Three reagent grade solvents, carbon tetrachloride, benzene, and isopropyl alcohol, and three commercial grade solvents, heptane, hexane, and tetrachloroethylene, were evaluated as extractants for the liquid wax from jojoba. Soxhlet-type of extractions were carried out under conditions in which the solvent was the only significant variable. Four of the solvents extracted essentially the same amount of material from the seed while isopropyl alcohol extracted significantly more material and tetrachloroethylene significantly less. Obviously the difficulties involved in separating the solids recovered from the isopropyl alcohol extraction preclude its use as the extracting solvent for jojoba wax. The density of the liquid waxes varies from 0.8631 to 0.8648; the waxes from the tetrachloroethylene and hexane extractions had the lowest value and the wax from isopropyl alcohol the highest. In each case, regardless of the solvent used, a precipitate developed in the liquid wax after it had been desolventized and stored for 7–10 days. Hydrogenation of clear fractions and precipitate containing fractions of these liquid waxes showed that the precipitate had no apparent effect upon the melting point or hardness of the resulting solid wax. Some of the liquid waxes required a longer hydrogenation time to attain an iodine value of about 1. At this iodine value all of the solid waxes had melting points between 66 and 68°C. Hardness values of all the solid waxes as measured by the Trionic hardness gauge were 90. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Synthesis of Wax Esters from Crude Fish Fat by Lipase of Burkholderia sp. EQ3 and Commercial Lipases

The lipase from Burkholderia sp. EQ3 was used to synthesize wax esters in comparison with commercial lipases. The supernatant of Burkholderia sp. EQ3 was collected from a liquid basal medium with 1 % fish oil after 12 h cultivation (1.90 U/ml of lipase activity). The crude lipase was prepared by acetone precipitation of the culture supernatant (4.70 U/mg and 9.40 purification folds). The crude fish fat obtained by hexane extraction of waste fat from the wastewater pond of a canned tuna factory and cetyl alcohol were used for wax esters synthesis. Five commercial lipases were screened in comparison with crude lipase from Burkholderia sp. EQ3 in wax esters synthesis. The optimum conditions for wax esters synthesis from crude fish fat using Novozyme 435 were enzyme 1 U, substrate molar ratio of crude fish fat to cetyl alcohol 1:2 (115.30 mg of crude fish fat and 66.67 mg of cetyl alcohol) in hexane at 37 °C and 200 rpm with 90.81 % (TLC–FID peak area) after one h of reaction. The optimum conditions for the synthesis by crude lipase from Burkholderia sp. EQ3 were crude lipase 40 U, substrate molar ratio of crude fish fat and cetyl alcohol 1:2 in isooctane at 30 °C and 200 rpm with 95.07 % (TLC–FID peak area) after 6 h of reaction. The synthesized wax esters were mainly composed of cetyl palmitate and cetyl oleate.     

Further Investigations on Cane Wax Refining and Bleaching

The crude wax from Egyptian sugar contains ash, which probably consists of soaps and phosphatides. After the inorganic material has been eliminated by heating with hydrochloric acid, a soft wax of higher acidity remains. The acid and the softer components of the wax may be readily distilled under low pressure in steam, leaving as a residue a hard dark wax, which is odourless, contains little acid material and is comparable with hard, dark waxes obtained by solvent process of refining. The distillates from the low pressure distillation are pale yellow-brown pastes. The effect of different chemical bleaching agents on bleaching of hard wax is reported. Chromic acid was found to be much superior to other bleaching agents examined. The hard wax obtained, whether from the low pressure refining or from solvent refining, are readily converted by this agent into pale hard, glossy waxes having high acid values.     

Wax composition of sunflower seed oils

Waxes are natural components of sunflower oils, consisting mainly of esters of FA with fatty alcohols, that are partially removed in the winterization process during oil refining. The wax composition of sunflower seed as well as the influence of processing on the oil wax concentration was studied using capillary GLC. Sunflower oils obtained by solvent extraction from whole seed, dehulled seed, and seed hulls were analyzed and compared with commercial crude and refined oils. The main components of crude sunflower oil waxes were esters having carbon atom numbers between 36 and 48, with a high concentration in the C₄₀−C₄₂ fraction. Extracted oils showed higher concentrations of waxes than those obtained by pressing, especially in the higher M.W. fraction, but the wax content was not affected significantly by water degumming. The hull contribution to the sunflower oil wax content was higher than 40 wt%, resulting in 75 wt % in the crystallized fraction. The oil wax content could be reduced appreciably by hexane washing or partial dehulling of the seed. Waxes in dewaxed and refined sunflower oils were mainly constituted by esters containing fewer than 42 carbon atoms, indicating that these were mostly soluble and remained in the oil after processing.     

Phase transitions of canola oil sediment

Canola sediment was obtained from an industrial filter cake by solvent extraction. When heated in the differential scanning calorimeter (DSC) (5–100°C), the sediment exhibited a single narrow melting peak at around 74.8°C. No solid-state polymorphic transformation of the material could be detected over this temperature range. The X-ray powder diffraction pattern of canola sediment resembled waxes from other sources with an orthorhombic unit cell. The phase transition behavior of canola sediment in oil was studied by both DSC and polarizing microscopy. With increasing ratio of oil/sediment, a reduction in both melting temperature and transition enthalpy was observed. The shape of the supercooling curve resembled that of the melting curve. The induction time was determined by spectrophotometry and was used to calculate the interfacial free energyσ between sediment and oil; σ=4.71 erg/cm². The effect of temperature and sediment concentration on the clouding time of canola oil was studied; the clouding time was the shortest at 5°C.     

Purification of 2-mercaptobenzothiazole by solvent extraction

−Purification of 2-mercaptobenzothiazole (91.9% purity) by solvent extraction was studied. The extraction of impurities present in crude 2-MBT (e.g. benzothiazole, sulfides and sulfur containing compounds) was carried out at temperatures between 70-180°C using various solvents and their mixtures of different polarity. The highest purity of 2-MBT, above 99% was obtained using nitrobenzene, toluene and ethanol, even at a concentration of 2-MBT above 50 wt%. Increasing temperature and decreasing concentration of the raw material have a positive influence on the purification process. A comparable efficiency of purification was observed also with mixed solvents, (toluene with ethanol, acetone and aniline) possessing the same polarities. A correlation between the polarity indexes (PI) of mixed solvents and experimentally obtained purity of 2-MBT was found. The highest purity of 2-MBT provides extraction of the raw material with mixed solvents having PI 3.8-4.4.     

Physikalisch-chemische Eigenschaften von Braunkohlenextrakten und abgetrennten Wachs- und Harzstoffen

Physico-chemical Properties of Brown-Coal Extracts and Separated Wax and Resin Substances The component composition and the physico-chemical properties of the raw montane wax Romonta as well as of three samples of the toluene extracts from the mine Turów, obtained at different extraction temperatures, were determined. The wax and resin substances were separated from the raw montane wax Romonta and from the toluene extract of brown-coal from the mine Turów, obtained at 100°C, and then characterized. The rheological properties of the extracts, the separated components and the four selected processing products of the raw montane waxes Romonta (means of hydrophobation Romonta 55, acid wax R, ester wax K-60, partly saponified ester wax REW II) were determined by the rotation viscosity metre Rheotest 2. The viscosity measurements were carried out at higher temperatures than the dropping point of the investigated substance, in case of extracts rich on resin also at lower temperatures. A significant influence of the sort of coal and the extraction temperature on the component composition of the obtained extracts as well as on the properties of the separated wax and resin substances was established. Furthermore a different rheological behaviour of the wax substances and wax containing extracts in comparison to the resin components of brown-coal bitumen was observed. Concerning the extracts of brown-coal from the mine Turów it was found out that the viscosity slowly increases in case of an increase of the resin content up to 50%, but at higher resin content it increases very quickly.     

Sunflower-Oil Wax Reduction by Seed Solvent Washing

Wax distribution in sunflower seeds was determined by capillary-gas chromatography, as well as both the wax composition in sunflower oils obtained from washed seeds and the wax composition in the solvent extracts. The dehulling efficiency was evaluated by using a laboratory centrifugal process. The washing effect on hull morphology and on wax distribution was observed by scanning-electron microscopy. Washing preferentially removed the crystallized fraction, hexane being the most effective solvent. Short contact times (20 s) at 25–40 °C were sufficient to extract the insoluble waxes by hexane washing. The extracted material consisted of C40–C54 waxes with higher percentages of extracted C44, C46 and C48. These are superficially in the hull of sunflower seed presenting a non-uniform distribution as observed by microscopy. Solvent washing with pre-heating of the seeds caused a decrease in sample moisture content, which reduced dehulling ability. Ethanol-washed seeds were the easiest to dehull, but higher production of fines was also observed. Solvent washing improves both the dehulling-seed ability increment and the recovery of sunflower waxes as a by-product for commercial use.     

Wax analysis of vegetable oils using liquid chromatography on a double-adsorbent layer of silica gel and silver nitrate-impregnated silica gel

A chromatographic method is described to measure the crystallizable wax content of crude and refined sunflower oil. It can also be applied to any other vegetable oil. The preparative liquid chromatography step on a glass column containing a silica gel adsorbent superimposed upon a silver nitrate-impregnated silica gel support is used to isolate a wax fraction which is then analyzed by gas chromatography. The recovered wax fraction contains, in addition to the crystallizable waxes, hydrocarbons and other compounds with gas chromatographic retention times corresponding to waxes with chain lengths C₃₄−C₄₂. These compounds are short-chain saturated waxes in fruit oils, such as grapeseed and pomace. In seed oils such as sunflower, soybean or peanut, the compounds initially referred to as “soluble esters” are identified as monounsaturated waxes, esters of long-chain saturated fatty acids, and a monounsaturated alcohol, mainly eicosenoic alcohol. Such waxes are absent from corn or rice bran oils.     

Composition of waxes from crude rice bran oil

Hard and soft waxes were separated from the tank settling of crude rice bran oil by solvent extraction and analyzed for their composition by gas liquid chromatography (GLC). The results showed that the melting points of the hard wax and the soft wax were 79.5 C and 74 C, respectively, and that the hard wax was mainly composed of saturated fatty alcohols of C24, C26 and C30, saturated fatty acids of C22, C24 and C26, andn-alkanes of C29 and C31. The soft wax was mainly composed of saturated fatty alcohols of C24 and C30, saturated fatty acids of C16 and C26, andn-alkanes of C21 and C29. In the soft wax, lauric acid was also detected.     

Separation of some paraffin wax grades using solvent extraction technique

Solvent extraction technique has been used to separate paraffin wax grades; with different characteristics; from El-Ameria light, middle and heavy slack waxes. The wax deoiling has been done by solvent extraction at different extraction temperatures and different solvent feed ratios (S/F by weight). The extraction solvents used are furfural, N-methyl-2-pyrrolidone (NMP) and N, N, dimethylacetamide (DMA). The wax products are evaluated according to TAPPI-ASTM equation and petroleum wax specifications. The data revealed that DMA and NMP are suitable extracting solvents for isolating of semi- and scale-refined grades of paraffin waxes from light and middle slack waxes. But furfural solvent can separate only semi-microcrystalline waxes from heavy slack wax.     

The compositions of some unhydrolyzed naturally occurring waxes,calculated using functional group analysis and fractionation by molecular distillation,with a note on the saponification of carnauba wax and the composition of the resulting fractions

Summary Methods for the determination of acid, ester, hydroxyl, and ketone (or aldehyde) groups and of mean molecular weights of small samples of natural waxes are reported. Complete analyses can be made on 0.5 g. of sample. A simplified procedure for quantitative separation of acid and unsaponifiable fractions of a wax is also reported. Molecular distillations of beeswax, caranda wax, crude and refined candelilla wax, and ouricury wax, have fractionated these complex mixtures into simpler ones. Hydrocarbons and free unsubstituted alcohols and acids, if present, distil readily at 150°C. A pot still suitable for convenient molecular distillation of up to 100-g. charges of waxes or other high melting materials is described. A method for the calculation of composition of unhydrolyzed waxes based upon function group analysis of molecular distillation fractions is described. Results of application of this method to the waxes distilled are reported and show the ubiquitousness of hydroxy acids. All of the above waxes and carnauba wax contain major proportions of esters of the hydroxy acids, and none contains as much as one-half simple esters of unsubstituted acids and alcohols. A portion of a dissertation submitted by Thomas Wagner Findley to the Graduate School of the Ohio State University in partial fulfilment of the requirements for the Ph.D. degree. S. C. Johnson and Son Inc. Fellow in Physiological Chemistry, 1946-50.     

Extraction of Surface Wax from Whole Grain Sorghum

Sorghum has potential as a domestic source of wax for applications in the food and nonfood industries. The waxes extracted from sorghum have similar physical properties to those of Carnauba wax, a common imported commercial wax. This work focused on the extraction, fractionation, and characterization of waxes from sorghum kernels. Extraction was performed by varying the extraction conditions including temperature and solvents (hexane, ethanol, and methanol). A fractionation technique was developed to separate and quantify waxes from nonwaxes. The fractions were then characterized using a reverse‐phase high‐performance liquid chromatography method developed in our laboratory that utilizes an evaporative light‐scattering detector for quantification. The results showed that the average amount of wax extracted from the surface of intact sorghum kernels was about 0.3 wt% using hexane at temperatures between 25 and 120°C and 1000 psi. The yield of wax via hexane extraction increased with temperature and ranged from about 0.06 to 0.39 wt%. Extraction with alcohols resulted in higher yields of extracts, but after fractionation to remove nonwax components, the yield of waxes was reduced by 31% for ethanol and 47% for methanol compared to hexane.     

选择性溶剂萃取生产低凝柴油的溶剂筛选和溶剂选择性的表征

酮类、酯类、氯代烃类溶剂分别对减一线油和常三线油进行了选择性萃取生产低凝柴油的实验。溶剂乙酸乙酯的选择性好,可降低减一线油和常三线油冷滤点分别为18°C和16°C,同时对柴油燃烧性能的影响较小,是选择性萃取生产低凝柴油的最佳溶剂。比较了各溶剂的脱蜡率、脱出的各碳数正构烷烃的质量分布和脱蜡油的冷滤点,引入了由高碳数正构烷烃脱出量、脱蜡率和冷滤点降低值三个因子组成的综合评价参数。该参数能表征本工艺要求的选择性,并直观地指导对两种油样均优的萃取溶剂的选择。     

Effect of the extraction and bleaching processes on jojoba (Simmondsia chinensis) wax quality

The aim of the work was to evaluate the effect of extraction method and bleaching on the quality of jojoba waxes from Argentina. Jojoba waxes obtained by cold pressing, Golden wax (expeller‐pressed wax) and Lite wax (bleached wax) were analyzed using standard methods adopted as recommended practices by the American Oil Chemists Society. Physical parameters, fatty acid and alcohol compositions were unchanged among waxes. Cold‐pressed wax was noteworthy by its lower peroxide value, higher amounts of tocopherol and total phenol contents. Accordingly, it presented the best oxidative stability. Bleaching caused a strong decrease in both tocopherol and phenol contents; consequently the bleached wax showed poor oxidative stability.     

Composition and physicochemical properties of corn wax

Corn wax, as a kind of vegetable wax, is a by-product of the corn oil industry. In this study, the corn wax was obtained from the corn oil refineries and purified by solvent defatting and bleaching. The composition and physicochemical properties of corn wax were studied to provide theoretical guidance for the production and application of corn wax. The results showed that the purity of corn wax was higher than 95%, and the corn wax ester ranged from C42 to C58, with C46, C44, and C48 being predominant. The carbon number of fatty acids was in the range of 16–30, with a higher proportion of C20, C22, and C24. The fatty alcohols varied from C20 to C32 and were dominated by C22, C24, C30, and C23. The physicochemical properties of corn wax were also determined and compared with other vegetable and animal waxes to get a more comprehensive understanding of corn wax. The results showed that the water content, iodine number, saponification number, and melting point of corn wax were 0.03 ± 0.01%, 6.77 ± 0.85 g/100 g, 74.31 ± 3.49 mg/g and 77.28 ± 7.89°C respectively. Corn wax was a green and healthy natural resource, which has great application potential in food, health care, and medicine.     

Extractable waxes from Greek lignites

An investigation on the solvent-extraction yields of Greek lignites has shown that the yields are generally low compared with the yields from certain American and German lignites, and similar to the yields from Czechoslovakian lignites. The highest yields were obtained from lignites of the Psachna deposit. The only extract which resembled rather closely in its nature the Riebeck crude montan wax was obtained by benzene extraction from Ptolemais lignite. The most significant differences between benzene extracts from Greek lignites and Riebeck crude montan wax were the differences in melting points and the greater resin content of the Greek waxes. Extraction with benzene/methanol mixture instead of benzene gave higher yields and extracts characterized by higher melting points, and higher acid and ester values. The compatibility of the extracts with paraffin wax was low; only benzene extract from Ptolemais lignite was completely miscible. No relation was found between the wax yield and the ratio volatile matter/fixed carbon of the coal. We also conclude that extraction of waxes from Greek lignites is not commercially attractive.     

Temperature‐dependent solubility of wax compounds in ethanol

The ability of ethanol to dissolve wax compounds, as an alternative to traditional lipid solvents, was investigated for the recovery of cuticular lipids from biomass. The solubilities of fatty esters with carbon chain lengths from 40 to 54 were measured in ethanol over a temperature range of 30–80°C. The greatest increase in solubility was observed between 40° and 60°C for the long chain waxes that are characteristic of flax cuticle lipids. The solubility of a 52‐carbon wax increased by a factor of four over this temperature range. The Van't Hoff equation was used to estimate enthalpy of solution values. Ethanol was an effective lipid solvent at these modestly elevated temperatures and offers an economical method to recover lipid co‐products from biomass prior to conversion to bioethanol.     

Rice brain oil. I. Oil obtained by solvent extraction

1. Freshly milled rice bran has been extracted with commercial hexane and the recovered oil and extracted meal examined for their respective content of wax. The oils were refined and bleached by standards as well as several special methods. The crude, caustic soda refined, and several refined and bleached oils were examined spectrophotometrically.
2. When freshly milled rice bran of good quality is extracted with commercial hexane, an oil of relatively low free fatty acid content is obtained. This oil possesses good color and is as stable as other similar types of crude oils.
3. If the oils is extracted from the brain at a temperature below about 10°C. and the extraction is discontinued at the right time, the extracted oil represents 90–95% of the total lipids in the brain and contains very little wax. This wax, which is readily extracted with hot commercial hexane as well as other types of solvents, amounts to about 3–9% of the total extractable lipids.
4. When subjected to ordinary caustic soda refining methods, good rice brain oils behave much like cottonseed oils of comparable free fatty acid content. Both caustic soda refining in a hydrocarbon solvent and refining with sodium carbonate result in refining losses approximating the absolute or Wesson loss.
5. Some of the refined oils when bleached according to usual practice produce products acceptable for use in the edible trade. However, refined rice bran oil has a definitely greenish cast resulting from the presence of chlorophyll, but this color can be removed by bleaching with a small amount of activated acidic clay.

     

Wax crosslinking with dicumyl peroxide

A Fischer—Tropsch paraffin wax of high molecular weight, congealing point 205°F (96·1°C), was crosslinked with dicumyl peroxide as initiator. At peroxide/wax molar ratios of less than 1·15 : 1, crosslinked waxes with molecular weights up to approximately double that of the starting material are obtained. These products are characterised by an increase in elasticity. At peroxide/wax ratios greater than 1·15 : 1 insoluble and infusible gels are formed. The efficiency and fate of the initiator and possible side reactions are discussed.