Tall oils components

DifficultSepa.ra.tions, Difficult separations, characterized by separation factors in the range 0.95 to 1.05, are frequentiy expensive because these involve high operating costs. Such processes can be made economically feasible by reducing the solvent recovery load (260) this approach is effective, for example, in the separation of m- and -cresol, Hnoleic and abietic components of tall oil (qv), and the production of heavy water (see Deuteriumand TRITIUM, deuterium). 

Tall oil fatty acids (TOFA) consist primarily of oleic andlinoleic acids and are obtained by the distillation of crude tall oil. Crude tall oil, a by-product of the kraft pulping process, is a mixture of fatty acids, rosin acids, and unsaponiftables (1). These components are separated from one another by a series of distillations (2). Several grades of TOFA are available depending on rosin, unsap oniftable content, color, and color stabiUty. Typical compositions of tall oil fatty acid products are shown in Table 1 (see Tall oil). 

Chemistry of rosin. All three types of rosin consist primarily of C20 mono-carboxylic diterpene resin acids, the most common of which have the molecular formula C20H20O2. In addition, rosins contain small amounts of neutral and other acidic components (e.g. fatty acids in tall oil rosin). The neutral components of rosins are diterpene alcohols, hydrocarbons and aldehydes, and their contents generally vary between 5 and 15 wt%. 

Some useful by-products of pulping are derived from these extractives, the most important of which are turpentine and tall oil. Turpentine is a mixture of bicyclic hydrocarbons with the empirical formula C10H16, the dominant components of which are a- and /J-pinene (Figure 2.8). They are produced as volatile by-products at a yield of around 4-5 litres per tonne of wood (for pine) and are used as a solvent and as a chemical feedstock. 

Tall oil is made up mostly of resin acids with around 10% of neutral components. These resin acids are isomers or structurally close relatives of abietic acid (Figure 2.9) and are used as antislip agents, as a chemical feedstock and as paper-sizing agents (see Chapter 7). 

The spent black liquor from the kraft pulping of pines contains the less volatile products of the wood resin in the form of sodium salts or soaps. The liquor first is concentrated in multiple-effect evaporators, and then the concentrate is sent to settling tanks. The soaps rise to the surface, are skimmed off, and then are acidified with sulfurous or sulfuric acid. The crude tall oil rises to the top and is mechanically separated. Crude tall oil from southern pines contains 40-60 percent resin acids and 40-55 percent fatty acids with 5-10 percent neutral substances. These components are separated by fractional distillation under vacuum. 

The rosin component of tall oil is mostly made up of resin acids, which are diterpene derivatives. The major compounds (figures indicate averages) are as follow ... 

The fatty acids from tall oil have the following components oleic (50%), linoleic (35%), conjugated linoleic (8%), stearic (2%), palmitic (1%), and others (4%). From tall oil... 

The neutral or unsaponifiable materials present in tall oil include anhydrides, pheno-lics, diterpene aldehydes and alcohols, stil-benes, and steroids. In the neutral fraction of southern pine tall oil soap, 80 compounds have been identified. They include 25.1 percent sistosterol and a total of 32.4 percent steroids. The sistosterol content of crude tall oil is 2-3 percent and is the main component of the neutral fraction. 

Tall oil rosin production has recently been driven by demand for its co-product, tall oil fatty acid. United States production of tall oil rosin in 1994 was 265,000 metric tons, exceeding consumption by nearly 50,000 metric tons. Therefore, the rosin acid fraction of crude tall oil is an under-used byproduct in abundant supply, with attractive characteristics as a precursor to high value chemicals. Two components, abietic acid and dehydroabietic acid, con rise about 70% of the rosin acid fraction of tall oil. Therefore, it is a relatively single mixture, which is also a beneficial characteristic for its use as a feedstock. 

Tall oil, derived from the Swedish tallolja meaning pine oil, is recovered from the black liquor of softwood pulping. It is taken out at an intermediate stage of the multiple-effect evaporation when the liquor contains about 30% total solids, after it is allowed to stand [21]. The soaps (sodium salts of fatty acids present) are insoluble, cream to the top of the vessel, and are skimmed off. The residual black liquor is returned to the evaporators to continue chemical recovery. The soap yield, which can range from 10 to 200 kg/tonne of pulp (or even higher for pine), is then acidified and the free fatty acids and resin acids obtained are separated by distillation. The fatty acids recovered consist mainly of oleic and linoleic acids and are employed in soap manufacture and as the drying oil components of paints and varnishes [22] (Chap. 19). Resin acids consist of terpene acids such as abietic acid and its positional and reductive variants, and are mainly employed in paper sizing. 

In the kraft pulping of softwoods the resin acids and fatty acid esters present consume alkali required for delignification and are therefore undesirable. These can be recovered as tall oil by concentration of the spent liquor, separating off the acid soap (which also contains neutral components) and acidifying the sodium salts with sulphuric acid from which a blend of resin acids, fatty acids and neutrals is obtained. 

Diterpenes have, by definition, 20 carbon atoms in their structure. This means that very few are sufficiently volatile to possess an odour. One diterpene is used in perfumery because it and the derivatives concerned are odourless. That is, they are used as solvents. In view of their hydrophobicity and low volatility, these solvents also have fixative properties. Abietic acid is a major component of tall oil, the residue from distillation of turpentine. Esterification and hydrogenation produces two solvents, as shown in Scheme 4.36. 

A complex system is one containing so many components that they cannot be separated into discreet pure components by the distillation process. An example of such a system is naturally occurring petroleum, which contains hundreds of chemical constituents. Crude tall oil from paper pulping is another example of a complex system. 

The large supply of tall oils and the well-known surface properties of many of the components have led to several suggestions to use them or their derivatives in micellar flooding (X58.5 9.). However, there are, so far as we know, no extensive laboratory investigations underway nor plans to test these possibilities in the field. In view of the contribution tall oils might make to enhanced recovery if they could be used, a survey of interfacial tension properties of aqueous/hydrocarbon systems, similar to those which have become common with the petroleum sulfonate and other surfactants under consideration for micellar floods, seemed worthwhile. 

Crude tall oil is a mixture of fatty acids, resin acids, and neutrals (i.e., no carboxylic acid functionality). The background section relates that neutrals interfere with the separation of the fatty acids from the resin acids and in industrial practice the neutrals are removed by molecul distillation. However, it is difficult to separate the neutrals from the other components because of vapor pressure similarity considerations. Tall oil soap, the precursor to crude tall oil, is a pasty emulsion of the neutrals and the sodium salts of the fatty and resin acids. The patent states that it is possible to extract neutrals from the soap with a liquid hydrocarbon solvent, but the prior art discussion relates that subsequent liquid hydrocarbon solvent recovery steps are relatively difficult. The neutrals can be separated from the soaps by a hydrocarbon solvent, incidentally, because the neutrals are lipophiles whereas the soaps are ionic and do not dissolve in the hydrocarbon. Similarly the neutrals will dissolve in a supercritical fluid like ethylene, or propane, or the chlorofluorocarbons, and the use of these gases in the supercritical state is the invention. Like the case of liquid hydrocarbon solvents, the ionic soap compounds will not dissolve in the supercritical gases. CO2 is specifically not listed among the gases, and we shall discuss the case of CO2 extraction of the emulsion later which is the subject of the next patent. 

The process to extract chemical components from wood is shown in the figure. Wood chips are charged (batchwise) to the extractor 4. CO2 at conditions of about 1,175 psi and 40 °C is fed to the extractor via line 6. The extract stream consisting of organics such as tall oil and turpentine which dissolve in CO2 exits the extractor via line 12, and the stream is reduced stagewise in pressure in vessels 14,20, and 22. Depending upon the particular conditions of pressure and expansion, it is related that two fractions, tall oil and turpentine, or a plurality of fractions, individual terpenes, individual fatty acids, and individual resin acids, can be separated. 

Ammonium xylenesulfonate Caprylic/capric acid Chlorodiphenyl (54% Cl) 2-Ethylhexyl oleate Pentaerythrityl tetrabehenate Soy acid Tall oil y-Valerolactone cutting oils, metals Isopropanolamine cutting tools/dies Tantalum carbide cutting-tool component refractory Zirconium boride cyanamide mfg. 

Calcium dodecylbenzene sulfonate Glycidol PEG/PPG-17/6 copolymer PEG/PPG-35/9 copolymer PEG/PPG-125/30 copolymer Poloxamer 101 Poloxamer 105 Poloxamer 108 Poloxamer 122 Poloxamer 123 Poloxamer 124 Poloxamer 181 Poloxamer 182 Poloxamer 183 Poloxamer 184 Poloxamer 185 Poloxamer 188 Poloxamer 212 Poloxamer 215 Poloxamer 231 Poloxamer 234 Poloxamer 235 Poloxamer 237 Poloxamer 238 Poloxamer 282 Poloxamer 284 Poloxamer 288 Poloxamer 331 Poloxamer 333 Poloxamer 334 Poloxamer 335 Poloxamer 338 Poloxamer 401 Poloxamer 402 Poloxamer 403 Poloxamer 407 Stearyl hydroxyethyl imidazoline Tall oil hydroxyethyl imidazoline Tetrasodium dicarboxyethyl stearyl sulfosuccinamate demulsifier component, crude oil Nonoxynol Nonyl nonoxynol Phenol-formaldehyde sulfonate Polyethylene glycol demulsifier component, lubricant Nonyl nonoxynol Phenol-formaldehyde sulfonate... 

A food-grade oleic acid has been produced commercially from tall oil. The main uses of tall oil fatty acids are as intermediates in the production of oleochemicals and as components of alkyd resins. The absence of linolenic acid conveys good colour retention and non-yellowing properties for protective coatings. 

Regardless of its origin (gum, wood or tall oil), rosin is mainly composed (90-95 pa- cent) of diterpenic mono-carboxylic acids, commonly known as resin acids whose generic formula is C19H29COOH. The remaining components are essentially made up of neutral compounds, the nature of which depends on the specific origin of the rosin [5]. The most common resin acids found in pine rosin are derived from the three basic tricyclic carbon skeletons abietane, pimarane and isopimarane and the less common bicyclic labdane skeleton (Fig. 4.1). 

To illustrate another component of the forest products industry it may be instructive to take a brief look at the pine chemicals industry. The pine chemicals industry is not a new industry, but it is a very small portion of what is now known as the specialty chemicals industry, despite the fact that pine chemicals have been in active use for longer than the modern chemical industry era that arose in the early part of the 20th century. The pine chemicals industry has been extracting useful products such as turpentine and other simple materials for literally hundreds of years. With the rise of the pulp and paper industry, chemicals have in the majority been extracted from two waste streams crude tall oil and crude sulfate turpentine. Crude tall oil can be further separated into a fatty acid fraction, a tall oil fraction, a tail oil rosin fraction, and a tall oil pitch fraction. The crude sulfate fraction is separated into a variety of terpene monomers that can be further transformed into a variety of terpene resins. AH of these streams can be used as raw materials for coatings, various oil applications, surfactants, adhesives, inks, etc. [50]. 

C20H30O2. Product consisting chiefly of rosin acids in substantially pure form, separated from rosin or tall oil commercially for specific purposes and in which abietic acid and its isomers are the principal components. Syn Sylvie acid. 

PUs are formed as a result of a condensation or an adduction reaction between isocyanates and polyols [polyesters or polyethers with terminal hydroxyl (OH) groups, castor oil or tall oil]. If both components are more than difunctional, thermosetting end products are produced. Many auxiliary substances are also used in the manufacture of PU products. The hardening process can be modified by heat or with a catalyst [diamino diphenylmethane or meth-ylenedianiline (MDA), triethylenediamine, triethyl-amine, cobalt naphthenate or nickel salts]. Figure 1... 

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