Patent GB-914284-A (GB)
Title: Production of purified esters of pentaerythritols and polypentaerythritols
IPC: C07C31/24
Filed: 1959-02-25
Abstract: Resins, specifically vinyl and vinylidene halide resins and chloronitrile rubber, are plasticized by plasticizers consisting of or comprising esters having hydroxyl numbers not exceeding about 5,0 and acid numbers not exceeding 0,5 which esters are single esters derived from a branched alkanoic acid contains a total of 6 carbon atoms and having at least one C1-4 alkyl substituent in the 2- or 3-position or a mixture of alkanoic acids wherein each acid contains 4-8 carbon atoms, the acids collectively have an average of 5 to 6,5 carbon atoms and there is present about 50 to about 100% by weight of branched chain acids containing at least one C1-4 alkyl substituent in the 2- or 3-position, the esters also being derived from (1) pentaerythritol, di-pentaerythritol or tripentaerythritol, (2) a mixture of mono-pentaerythritol and at least one polypentaerythritol, the mixture averaging not more than three pentaerythritol residues per mole or (3) a mixture of poly-pentaerythritols averaging not more than 3 pentaerythritol residues per mole, the esters being obtained in specified manner (see Group IV(b)).  Specified resins are polyvinyl chloride, polyvinylidene chloride and copolymers of vinyl and vinylidene chlorides with one another or with minor amounts of other comonomers such as vinyl acetate, vinyl propionate, vinyl butyrate and methyl methacrylate.  The plasticizing esters may be used with other plasticizers such as dibutyl phthalate, di-n-decyl phthalate and 2-ethyl hexyl phthalate and with anti-oxidants, such as phosphites, amines and phenols, and with stabilizers, pigments, colours and fillers.  The plasticized polymers are particularly useful as coatings for electrical conductors. Specified polymer compositions consist of polyvinyl chloride, a plasticizer ester, tribasic lead sulphate, clay and paraffin wax. Typical plasticizers are the hexaesters of dipentaerythritol and 2-methyl pentanoic acid or a mixture of n-hexanoic, 2-methyl pentanoic and 3-methyl pentanoic acids; pentaerythritol tetra-2-ethyl butyrate; tripentaerythritol octa-2-ethyl butyrate; and the octa 2-methyl pentanoate of a mixture of mono-, diand poly-pentaerythritols averaging tri-pentaerythritol. Specification 884,660 is referred to.ALSO:Single esters or mixtures of esters wherein the alcohol moiety or moieties are derived from (1) pentaerythritol, di-pentaerythritol or tri-pentaerythritol, (2) a mixture of pentaerythritol and at least one poly-pentaerythritol, in which mixture the average number of pentaerythritol residues per mole does not exceed three, or (3) a mixture of at least two poly-pentaerythritol in which the average number of pentaerythritol residues does not exceed three, and the acid moiety or moieties are derived from (1) a branched alkanoic acid containing a total of 6 carbon atoms and having at least one C1-4 alkyl substituent in the 2- or 3-position or (2) a mixture of alkanoic acids in which each acid contains 4-8 carbon atoms, in which collectively the acids have an average of 5 to 6.5 carbon atoms and in which there is present from about 50 to about 100% by weight of branched acid or acids containing at least one C1-4 alkyl substituent in the 2- or 3-position, the esters or ester-mixtures having a hydroxyl number not above about 5.0 and containing such an amount of free carboxylic acid distillable under the conditions hereinafter specified that the ester or ester-mixture has an acid number greater than 0.5, are purified by stripping the free carboxylic acid from the ester material while the latter is in contact with activated carbon, the stripping being effected under a reduced pressure not exceeding 80 mm. Hg. and at about 120 DEG  to about 240 DEG C. the selected temperature being below the decomposition temperature of the ester, the stripping being continued until the product has an acid number not exceeding 0.5. The free carboxylic acid may be an aliphatic carboxylic acid, especially an alkanoic acid whose moiety is in the ester or esters being treated.  The esters to be purified may be prepared by reacting the polyol(s) with the alkanoic acid(s) at about 120 DEG  to about 240 DEG C., until the product has a hydroxyl number not exceeding about 5.0.  The carboxylic acid required for the stripping step may be provided by adding the acid to the ester before the stripping or by using excess of alkanoic acid in the esterification, this excess may range from 5 to 200 mole %.  The activated carbon required in the stripping step may also be added at the esterification stage; the activated carbon used is preferably neutral initially.  The esterification may be effected in the presence of a water-entrainer. The purified esters may be used as lubricants, stabilizers or pour-point depressants but more particularly as resin plasticizers (see Group IV(a)).  Typical examples describe the preparation and purification, by the above method, of esters from (1) dipentaerythritol and excess of a mixture of isobutyric, n-hexanoic and 2-ethyl butyric acids; (4) a mixture of mono-, di- and tri-pentaerythritols and excess of 2-ethyl butyric acid; (5) tripentaerythritol and excess of 2-methyl pentanoic acid; (6) a mixture of mono-, di-, tri-and higher poly-pentaerythritols, averaging tri pentaerythritol, and excess of a mixture of 2-methyl butyric acid and caprylic acid; and (7) pentaerythritol and excess of ethyl butyric acid. Specifications 615,370, 757,564 and 884,660 are referred to.