Patent GB-740155-A (GB)
Title: Improvements in or relating to preservatives, methods of making the same and substances employing the same
IPC: C08K5/375
Filed: 1951-05-23
Abstract: Resinous products are stated to be obtained when a phenol of the formula <FORM:0740155/IV(a)/1> is condensed with a sulphur dihalide, particularly if a solvent is not used or if the proportion of sulphur halide to phenol is greater than 1 : 2.  In the formula R is C1-C15 alkyl and R1 is C2-C12 alkyl or aralkyl, both groups being attached to the nucleus by primary carbon atoms.ALSO:The invention comprises symmetrical phenol sulphides of the formula <FORM:0740155/IV(a)/1> where R is C1-C15 alkyl and R1 is C2-C12 alkyl or aralkyl, both groups being attached to the nucleus by primary carbon atoms.  These products, which are antioxidants, are obtained by treating the appropriate phenols with sulphur dichloride or other dihalide, preferably in an inert solvent such as petroleum.  Two mols. of phenol are used per mol. of sulphur dihalide.  Preferred compounds are those in which R is methyl or ethyl and R1 is a straightchain alkyl group, a benzyl group or a C6-C12 branched chain alkyl group. Examples show the production of sulphides from 3-ethyl-6-n-propylphenol and 3:6-diethylphenol.  Other products mentioned are those from 3-methyl-6-ethylphenol, 3 - methyl - 6 - n - propylphenol, 3 - methyl - 6 - n - butylphenol, 3 - methyl - 6 - isoamylphenol, 3 - methyl - 6 - n - hexylphenol, 3 - methyl - 6 - isohexylphenol, 3 - methyl - 6 - n - heptylphenol, 3 - methyl - 6 - n - octyl - phenol, 3 - methyl - 6 - n - decylphenol, 3 - methyl - 6 - n - dodecylphenol, 3 - methyl - 6 - benzylphenol, 3-ethyl-6-n-butylphenol and 3-n-pentadecyl-6-ethylphenol.  The above phenols are made by Clemmensen reduction of the hydroxyketones R-C6H3 (OH)-CO-R11 (where R11 represents R1 less a -CH2-group), or, where R1 has 6-12 carbon atoms, by alkylation of R-C6H4OH with an olefine or alcohol.  Hydroxy - ketones R-C6H3(OH)-CO-R11, where R is C1-15 alkyl and R11 is alkyl, aryl or aralkyl of less than 12 carbon atoms are made by Fries rearrangement of the esters (m-)R-C6H4-O-CO-R11.  Thus are prepared 3-methyl - 6 - acetylphenol, 3 - methyl - 6 - propionylphenol, 3 - methyl - 6 - n - butyrylphenol, 3 - methyl - 6 - isovalerylphenol, 3 - methyl - 6 - caproylphenol, 3-methyl-6-isocaproylphenol, 3-methyl - 6 - n - heptoylphenol, 3 - methyl - 6 - caprylylphenol, 3 - methyl - 6 - caprylphenol, 3 - methyl - 6 - laurylphenol, 3 - methyl - 6 - benzoylphenol, 3 - ethyl - 6 - acetylphenol, 3 - ethyl - 6 - propionylphenol, 3 - ethyl - 6 - n - butyrylphenol and 3 - n - pentadecyl - 6 - acetylphenol.  Phenol esters (m-) R-C6H4-O-CO-R11 are obtained from the corresponding phenol and acyl halide, except for acetates (from acetic anhydride). Those described are m-tolyl acetate, propionate, n-butyrate, isovalerate, caproate, isocaproate, heptoate, caprylate, n-dodecanoate and benzoate, m-ethylphenyl acetate, propionate and n-butyrate, and m-pentadecylphenyl acetate.ALSO:Antioxidants for mineral oils, vegetable oils and soap comprise symmetrical phenol sulphides of the formula <FORM:0740155/III/1> where R is C1-C15 alkyl and R1 is C2-C12 alkyl or aralkyl, both groups being attached to the nucleus by primary carbon atoms.ALSO:Symmetrical phenol sulphides of the formula <FORM:0740155/V/1> where R is C1-C15 alkyl and R1 is C2-C12 alkyl or aralkyl, both groups being attached to the nucleus by primary carbon atoms, are used as antioxidants for elastomers such as natural or reclaimed rubber, balata, gutta-percha and butadiene-styrene copolymers.  They may be incorporated into rubber by milling, added to latex before coagulation or applied to the surface of a crude or vulcanized elastomer.  Amounts of 0.5-3.0 per cent are suitable.  In an example the antioxidant is blended with smoked sheet rubber, zinc oxide, lithopone, sulphur, diphenylguanidine phthalate, benzoylthio-benzthiazole and paraffin, and the mixture vulcanized. In specified antioxidants R is methyl, ethyl and n-pentadecyl and R1 is ethyl, n-propyl, n-butyl, isoamyl, n-hexyl, isohexyl, n-heptyl, n-octyl, n-decyl, n-dodecyl and benzyl.