Fatty acids from wood

Fatty Acids. Of the total fatty acids produced annually in the United States, amounting to more than 450,000 tons, 35 percent come from tall oil. The solvent extraction of pine wood yields only 1 percent fatty acids and their esters. The yield is not increased, however, by paraquat (dipyridyl herbicides) treatment. Hence, the kraft-pulping industry will continue to be the major source of fatty acids from wood. The approximate distribution of uses of the fatty acids are ... 

Sodium and Potassium Salts of Tall Oil Acids (Tall oil, a by-product of paper manufacture, is a mixture of fatty acids and rosin acids from wood 50-70% fatty acid, mainly oleic and linoleic, 30 -50% rosin acids related to abietic acid, the main constituent of rosin.) Mainly captive use or in situ preparation for various industrial cleaning operations. Used as foaming agents for concrete. 

Supercritical CO2 has been considered as a potential alternative to conventional solvents due to its relative non-toxicity and non-flammability, as well as its low critical temperature and pressure. Supercritical fluid extraction (SFE) has been used for example in the extraction of fatty acids from diverse matrices such as grape seeds , ginseng seeds, wood pulp , and infant formula . The absence of oxygen and light during the supercritical extraction process helps prevent degradation of the extract. For example, Tipsrisukond, et al." found... 

Figure 5.7 Reversed-phase high-pressure liquid chromatogram of phenacyl ester derivatives of the fatty acids from cottonseed cotyledons and embryos. CIS (50 nun x 4.5 nun, 3 pm particle size) and C8 (150 nun x 4.5 nun, 5 pm) were used in tandem. The mobile phase was composed of acetonitrile and water, and the flow rate was 1.5 ml min . An initial mixture of acetonitrile/ water (80 20 vol./vol.) was maintained for 25 min, followed by a gradient to acetonitrile/water (85 15) for a further 10 min and then to 100% acetonitrile for a final 10 min. A variable-wavelength detector was employed. Redrawn from Wood, R., Comparison of the cyclopropene fatty acid content of cottonseed varieties, glanded and glandless seeds, and various seed structures, Biochem. Arch., 2, 73-80, 1986.

Usmani and Wahab ° determined the adsorption of lower aliphatic and some organic unsaturated fatty acids from their aqueous solutions on activated carbons prepared from wood, rice husk, and lignite coal. The adsorption depended on the porosity and the chemical stfucture of the carbon surface. It was also found that for a given acid the adsorption depended on the polarity of the carboxylic group, the length of the side chain, and the nature of the type of bonding. The adsorption followed both the Langmuir and the Freundlich adsorption equations. 

Xanthates and dithiophosphates dominate sulfide flotation usage, though several other collectors including more recently developed ones are gaining acceptance rapidly (43). As of this writing, this is an active area of research. Many of the sulfide collectors were first used ia the mbber iadustry as vulcanizers (16). Fatty acids, amines, and sulfonates dominate the nonsulfide flotation usage. The fatty acids are by-products from natural plant or animal fat sources (see Fats and fatty oils). Similarly petroleum sulfonates are by-products of the wood (qv) pulp (qv) iadustry, and amines are generally fatty amines derived from fatty acids. 

Tall oil rosin is a by-product of paper manufacturing. Raw wood chips are digested under heat and pressure with a mixture of sodium hydroxide and sodium sulfide. Soluble sodium salts of lignin, rosin, and fatty acids are formed, which are removed from the wood pulp as a dark solution. The soaps of the rosin and fatty acids float to the top of the mixture, where they are skimmed off and treated with sulfuric acid to free the rosin and fatty acids. This mixture, known as cmde tall oil (CTO), is refined further to remove color and odor bodies fractional distillation separates the tall oil rosin acids from the fatty acids (see Tall oil). 

Eatty acid soap was first used for ESBR. Its scarcity prompted the investigation of rosin acids from gum and wood as substitutes (1). The discovery of the disproportionation of rosin allowed rosin acid soaps to overcome the polymerization inhibition of untreated rosin acids. Rosin acid soaps gave the added benefit of tack to the finished polymer. In the 1990s, both fatty acid and rosin acid soaps, mainly derived from tall oil, are used in ESBR. 

Wood is the raw material of the naval stores iadustry (77). Naval stores, so named because of their importance to the wooden ships of past centuries, consist of rosin (diterpene resin acids), turpentine (monoterpene hydrocarbons), and associated chemicals derived from pine (see Terpenoids). These were obtained by wounding the tree to yield pine gum, but the high labor costs have substantially reduced this production in the United States. Another source of rosin and turpentine is through extraction of old pine stumps, but this is a nonrenewable resource and this iadustry is in decline. The most important source of naval stores is spent sulfate pulpiag Hquors from kraft pulpiag of pine. In 1995, U.S. production of rosin from all sources was estimated at under 300,000 metric tons and of turpentine at 70,000 metric tons. Distillation of tall oil provides, in addition to rosin, nearly 128,000 metric tons of tall oil fatty acids annually (78). 

Tall oil rosin is obtained from crude tall oil obtained from the Kraft (sulphate) pulping of various coniferous trees in the paper manufacturing industry. During the Kraft pulping process the fatty acids and the resin acids from the coniferous wood are saponified by the alkaline medium. On concentration of the resulting pulping liquor, the sodium soap of these mixed acids rises to the surface from where they are skimmed out. By acidification of this material with sulphuric acid, the crude tall oil is obtained. Fractional steam distillation of the crude tall oil allows the separation of the tall oil fatty acids and the tall oil rosins [21]. 

Where resorcinol adhesives are not suitable, resins can be prepared from modified resorcinol [128], Characteristic of these types of resins arc those used for tyre cord adhesives, in which a pure resorcinol-formaldehyde resin is used, or alternatively, alkyl resorcinol or oil-soluble resins suitable for rubber compounding are obtained by prereaction of resorcinol with fatty acids in the presence of sulfuric acid at high temperature followed by reaction with formaldehyde. Worldwide more than 90% of resorcinol adhesives are used as cold-setting wood adhesives. The other most notable application is as tyre cord adhesives, which constitutes less than 5% of the total use. 

Acylglycerols can be hydrolyzed by heating with acid or base or by treatment with lipases. Hydrolysis with alkali is called saponification and yields salts of free fatty acids and glycerol. This is how soap (a metal salt of an acid derived from fat) was made by our ancestors. One method used potassium hydroxide potash) leached from wood ashes to hydrolyze animal fat (mostly triacylglycerols). (The tendency of such soaps to be precipitated by Mg and Ca ions in hard water makes them less useful than modern detergents.) When the fatty acids esterified at the first and third carbons of glycerol are different, the sec-... 

Beef fat reacting to alkaline wood ashes led to the creation of the earliest soap, and it has been the cleaning product of choice for millennia. Soap is made from a fatty acid that is reacted with an alkali. The acid end of the fatty acid reacts with the alkali to form a salt that is water soluble. The other end is the fatty end, which repels water and is attracted to fats and oils. The process of making soap is called saponification. 

The alkaline product from the wood ash was a crude solution of sodium and potassium carbonates called "lye". On boiling the vegetable oil with the lye, the soap (sodium and potassium salts of long chained fatty acids) separated from the lye due to the dispersive interactions between the of the fatty acid alkane chains and were thus, called "lyophobic". It follows that "lyophobic", from a physical chemical point of view, would be the same as "hydrophobic", and interactions between hydrophobic and lyophobic materials are dominantly dispersive. The other product of the soap making industry was glycerol which remained in the lye and was consequently, termed "lyophilic". Thus, glycerol mixes with water because of its many hydroxyl groups and is very polar and hence a "hydrophilic" or "lyophilic" substance. 

Tall Oil Fatty acids and some unsaponifiable material obtained as a major byproduct from the sulfite-pulping process of wood. 

Most of the sulfur in plants occurs in proteins, especially in the amino acids cysteine and methionine. Other essential compounds that contain sulfur are coenzyme A, a compound essential for cellular respiration and for the synthesis and breakdown of fatty acids, and the vitamins thiamine and biotin. Sulfur can be absorbed by leaves as gaseous sulfur dioxide, S02, an environmental pollutant released from active volcanoes and from the burning of wood or fossil fuels. 

Additives. Because of their versatility, imparted via chemical modification, the applications of ethyleneimine encompass the entire additive sector. The addition of PEI to PVC plastisols increases the adhesion of the coatings by selective adsorption at the substrate surface (410). PEI derivatives are also used as adhesion promoters in paper coating (411). The adducts formed from fatty alcohol epoxides and PEI are used as dispersants and emulsifiers (412). They are able to control the viscosity of dispersions, and thus facilitate transport in pipe systems (413). Fatty acid derivatives of PEI are even able to control the viscosity of pigment dispersions (414). The bigb nitrogen content of PEIs has a flame-retardant effect. This property is used, in combination with phosphoms compounds, for providing wood panels (415), cellulose (416), or polymer blends (417,418) with a flame-retardant finish. 

Some cholesterol entering from the diet may be esterified to various fatty acids, although the extent of esterification is variable. For example, egg yolk cholesterol is about 10% esterified (Bitman and Wood, 1980 Tattrie, 1972) cholesterol in meat and poultry is at least 50% esterified (Kritchevsky and Tepper, 1961). Esterified cholesterol entering the intestinal tract is mostly hydrolyzed by pancreatic enzymes, yielding free cholesterol and fatty acids (Howies et al., 1996). Only unesterified cholesterol is available for absorption. 

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