GB805367A - Process of preparing acetoxy derivatives of unsaturated esters - Google Patents

Abstract

Plasticizers for polyvinyl resins comprise esters containing at least two acetoxy groups (and substantially no hydroxy or epoxy groups) obtained by adding acetoxy groups across the double bond(s) of esters unsaturated in the acid or alcohol portion or both. Specified compounds are butyl 9 : 10-diacetoxystearate, 2-ethylbutyl 9 : 10-diacetoxy-stearate, diacetoxystearyl butyrate and analogous products from soybean oil and cottonseed oil. Other suitable starting materials are mentioned. The resin may be polyvinyl chloride or a copolymer thereof with vinyl acetate or vinylidene chloride. Specifications 739,609, [Group IV (b)], and 741,492 are referred to.ALSO:<PICT:0805367/IV (b)/1> Esters containing two or more acetoxy substituents are prepared as follows: a waterinsoluble ester containing one or more double bonds in the alcohol or acid residue or both is treated with an aqueous mixture of acetic acid (and/or anhydride), hydrogen peroxide and an ionizable auxiliary acidic agent, whereby a product is obtained having hydroxy and acetoxy groups, and possibly epoxy groups as well; such product is then separated and acetylated to convert all the hydroxy and epoxy groups to acetoxy groups; the first step is carried out at a temperature between 10 DEG C. and the boiling point and at a pH of + 1.5 to - 1.5; the acetic acid (or equivalent of anhydride) is present in an amount of 0.3-2.5 mol. per double bond of ester and the hydrogen peroxide at least 1 mol. per double bond of ester; the concentration of hydrogen peroxide relative to the total amount of acetic compound used is such as falls within the area A, B, D, C, in the diagram. The auxiliary acidic agent is preferably a strong mineral acid such as phosphoric, sulphuric, hydrochloric or nitric; other suitable agents are boric acid, bisulphates, acid esters of sulphuric and phosphoric acid, sulphonic acids, potassium persulphate and zinc chloride. The agent must not be such that more than 35 per cent of the hydroxy, acetoxy and (if any) epoxy groups are decomposed. The acidic agent, acetic compound and hydrogen peroxide are preferably added portionwise or continuously over a period of time, the last two being added separately. Peracetic acid is thus formed in situ. The separation of the mixture into aqueous and organic phases is facilitated by the presence of a water-immiscible solvent such as benzene, toluene or ethylene dichloride. The organic phase is separated, heated to remove water and solvent and then acetylated under anhydrous conditions, e.g. with acetic anhydride or a mixture of acetic acid and ketene. This step is preferably carried out at a temperature from 100 DEG C. to the boiling point in the presence of a neutral or slightly basic salt (e.g. sodium acetate) as catalyst. Examples show the treatment of butyl oleate (giving butyl 9 : 10-diacetoxystearate), 2-ethylbutyl oleate, oleyl butyrate, soybean oil and cottonseed oil. In general, the starting material may be (1) an ester of an unsaturated fatty acid with an alkanol, glycol, polyglycol, glycerol, pentaerythritol, cyclohexanol or benzyl alcohol, or mixture of such esters; additional materials of this type are ethyl and hexyl oleates, octyl, dodecyl, benzyl and cyclohexyl linoleates, octyl and dodecyl linolenates, and safflower, sunflower, corn, sesame, poppyseed, walnut, peanut, linseed and perilla oils; (2) fatty acid esters of unsaturated alcohols such as oleyl, linoleyl and linolenyl alcohols; and (3) esters unsaturated in both acid and alcohol residues. Further compounds of these types are mentioned. The products are plasticizers for polyvinyl resins. Specifications 739,609 and 741,492 are referred to.