Fatty acid process

Fatty acid nitriles Fatty acid-oil process Fatty acid process... 

Fatty Acid Process. When free fatty acids are used instead of oil as the starting component, the alcoholysis step is avoided. AH of the ingredients can therefore be charged into the reactor to start a batch. The reactants are heated together, under agitation and an inert gas blanket, until the desired endpoint is reached. Alkyds prepared by the fatty acid process have narrower molecular weight distribution and give films with better dynamic mechanical properties (34). 

Non-drying oil resins are soluble only in Aromatic hydrocarbons. They are used with amino resins for stoving finishes for appliances. Medium resins are used as plasticisers for cellulose nitrate. Along with natural oils several natural occurring and synthetic acid like resin (abiotic acid) pelargonic acid and isooctanoic acid are added to modify alkye resins. The alkyd resins are obtained by two processes, i.e., (1) Fatty Acid Process and (2) Alcoholysis process. 

Fatty Acid Process In Fatty Acid Process the oil is hydrolysed to yield a fatty acid. A mixture of fatty acid, "dibasic acid and polyalcohol" are heated at 200-240°C in inert atmosphere. Sometimes small quantities of xylene is used as solvent. 

Different chemical procedures may be used for the synthesis of alkyd re si ns. The choice is usually dictated by the selection of the starting ingredients. Procedures include the alcoholysis process, the fatty acid process, the fatty acid-oil process, and the acidolysis process. 

Fatty Acid-Oil Process. When oil represents only a minor portion (33% or less) of the total furnish of fatty acids in an alkyd formulation, the alcoholysis step may be avoided. All of the ingredients, dibasic acid, polyol, oil, and free fatty acids may be charged together into the reactor and proceed as in the fatty acid process. Apparently, the oil is incorporated into the resin by ester interchange at the reaction... 

Su X., Han X., Mancuso D.J., Abendschein D.R., Gross R.W. Accumulation of long-chain acylcarnitine and 3-hydroxy acylcarnitine molecular species in diabetic myocardium identification of alterations in mitochondrial fatty acid processing in diabetic myocardium by shotgun lipidomics. Biochemistry 44 (2005) 5234-5245. 

There are two main methods for preparation of alkyd resins. In the first one, called the fatty acid process, a free fatty acid is coesterified directly with the dibasic acid and the polyol at 200-240 °C. The reaction may be carried out without a solvent by first heating in an inert atmosphere. At the end, an inert gas may be blown into the resin from the bottom of the reaction kettle to remove water and unreacted materials. As a modification of this, a small quantity of a solvent may be used to remove water of esterification continuously by azeotropic distillation with the aid of moisture traps. 

In this process polyol, dibasic acid and fatty acids are made to react simultaneously at a temperature of 220-260°C until the desired polyester is obtained. In this process, fatty acids compete with the phthalic anhydride and the phthalate half ester for the available hydroxyl groups. In a special modification of the fatty acid process developed by Kraft, the dibasic acid... 

This process involves the direct reaction of fatty acid, oil, polyol and dibasic acid. The ratio of fatty acid to oil must be such that a homogeneous reaction mixture results. This process has a cost advantage over the fatty acid process and gives a polyester with high viscosity, where the fatty acid represents 60-65% of the total of fatty acids and oil. Heat-polymerised oil will produce a polyester resin with an even higher viscosity. ... 

TTiere are two processes for making alkyd resins, the fatty acid process, in which the three components are heated together at around 200 C, and the monoglyceride process in which the oil and polyol are first heated together to form partial glycerides, which are then reacted with the polycarboxylic acid or its anhydride. In the latter case the glycerol of the oil forms part of the total polyol component. 

Fatty acids processed into VLDL (Figure 40.1)... 

Higher quality, higher performance alkyds are produced in the fatty acid process where the composition of the resulting resin can be more precisely controlled. In this process the following are combined and cooked together until the product has achieved a predetermined level of viscosity. 

Alkyd resins cannot be prepared by simply heating a mixture of oil, polyol and dibasic acid. Because of the preferential reaction of the polyol and acid, a heterogeneous mixture of polyester and oil is obtained which has no value as a surface coating vehicle. There are two main methods whereby useful resins are prepared commercially, namely the fatty acid process and the alcoholysis process (often called the monoglyceride process). 

After the monoglyceride is formed, the dibasic acid is added and the mixture is treated as in the fatty acid process again either the fusion method or the solvent method may be employed. Acidolysis is an alternative to alcoholysis, but generally requires a higher temperature and is seldom used. Compared to the fatty acid process, the alcoholysis process gives less reproducible results but is usually cheaper to run. 

As indicated earlier, materials based on a structure of this type are brittle and of little practical use however, the incorporation of fatty acid residues into such a structure leads to highly successful surface coating vehicles. The detailed structure of the latter materials depends on the method of preparation. In the fatty acid process (Section 10.5.4.1.), the polyol, dibasic acid and fatty acids react simultaneously and it has been shown [8] that the primary hydroxy groups of glycerol react more readily with phthalic carboxy groups than with fatty acids whilst the reverse applies to the secondary hydroxy groups. It is to be expected, therefore, that in an alkyd resin prepared by the fatty acid process the following type of structure would predominate ... 

The alcoholysis process has lower raw material costs than the fatty acid process but higher production costs, since it is a two-step process. The decision whether to produce from oil or from fatty adds is thus largely based on the amount of od/fatty adds in the formulation (see short oil/long oil resins, discussed in Section 16.5.4). 

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