Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Patent
1986-02-20
1987-09-15
Lone, Werren B.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
560 61, 562478, C07C 6703
Patent
active
046940995
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention concerns a procedure for producing stearyl-.beta.-(3,5-dibutyl-4-hydroxyphenyl)propionate (I) and bis-(.beta.(3,5-dibutyl-4-hydroxybenzyl)-methyl-carboxyethyl)-sulphide (II). Said products conform chemically to formulate I and II below and they are used mainly for stabilizing substances in rubbers and plastics. ##STR2## It is known in the art that these compounds can be produced in a two-step synthesis comprising (A) the addition reaction between alkylacrylate (III) and 2,6-dibutylphenol, and exchange esterification (B) of the product obtained (IV). ##STR3## In the procedures of prior art, step (A) is usually carried out in the presence of alkali catalysts, either as a molten state reaction or using a solvent for fluid. The exchange esterification step (B), again, has been performed in the procedures of prior art using either alkaline or acid catalysts.
SUMMARY OF THE INVENTION
The procedure of the invention differs from procedures of prior art particularly in that the exchange esterification step is carried out using esters of titanic acid for a catalyst. Morever, an advantage of the procedure of the invention is that when said catalysts are used the exchange esterification reaction is substantially faster, and thus the reaction time shorter, than in the procedures known in the art. An advantage of titanate catalysts is also that the use of fluid is unnecessary and therefore the production process is simpler.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The production of the products constituting the object of the invention may be further simplified if the propionic acid ester (IV) is produced in a way more closely described below, because then the crude product (IV) obtained as the reaction product can be used as starting material without recrystallization.
It should be noted, however, that propionic acid ester consistent with the chemical formula (IV), whatever the procedure by which it has been produced, is fit to be used for starting material when step (B) is carried out making use of the exchange esterification procedure of the invention.
In view of the invention, it is to be recommended that the propionic acid ester (IV) is produced by an addition reaction between 2,6-dibutylphenol and alkylacrylate (III) using alkali catalysts. Appropriate ones are, in that case, e.g. sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium-boron hydride, lithium-aluminium hydride, sodium and potassium tertiary butoxide, metallic sodium and potassium. 0.5-8% alkali catalyst, preferably 1-5%, calculated on the quantity of 2,6-dibutylphenol, are used.
It is possible in view of the invention that the step (A) is performed either as a molten state reaction or using a solvent for fluid. Solvents which are appropriate are then e.g. dimethylformamide, dimethylacetamide or dimethylsulphoxide, hexamethylphosphamide, acetonitrile, propionitrile or sulphonitrile, sulpholan, dimethylene glycol, tetrahydrofurane or tertiary butylalcohol. Of these, particularly tertiary butylalcohol is well suited to be used in the procedure of the invention. An appropriate quantity of the solvent is 5 parts by weight or less, preferably 0.1-1 parts by weight, of the quantity of 2,6-dibutylphenol.
It is recommendable in view of the invention that the molar proportion of alkylacrylate and 2,6-dibutylphenol in the addition step (A) is in the range 0.7-1.3, preferably 0.8-1.1, the reaction temperature is 60.degree.-130.degree. C., preferably 70.degree.-100.degree. C., and the reaction time is 2-12 h, preferably 6-8 h. All conventional mixing reactors are appropriate for accomplishing the reaction. It is furthermore recommendable in view of the procedure that it can be carried out in a nitrogen atmosphere. Propionic acid ester (IV) thus produced is sufficiently pure to be used as starting material for the purposes of the invention. However, the further use requires that the alkali catalyst is neutralized e.g. with the aid of carboxylic acids or mineral acids and that low-boiling impurities
REFERENCES:
patent: 4228297 (1980-10-01), Haeberli et al.
patent: 4376866 (1983-03-01), Englaender et al.
Kirk-Otmer Encyclopedia of Chemical Technology, Third Edition, vol. 23, pp. 179-181 and 225.
Ahlfors Matts
Idelman Peter
Koskimies Salme
Lahtinen Leila
Clarke Vera C.
Lone Werren B.
Neste Oy
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