Patent GB-996489-A (GB)
Title: Novel hydroxy thio benzamides
IPC: C08K5/36
Filed: 1962-05-24
Abstract: The invention comprises a hydroxythiobenzamide having the general formula <FORM:0996489/C2/1> wherein R1 and R2 are C1-C20 alkyl groups or C7-C20 aralkyl groups, R3 and R4 are each alkyl, cycloalkyl, aralkyl, aryl or alkaryl groups or R3 and R4 are groups which may be bonded together through an oxygen atom to form with the N atom depicted a morpholine ring.  They may be obtained (a) by heating sulphur with a compound having the formula <FORM:0996489/C2/2> wherein R1 to R4 are as defined above or by heating with sulphur a compound having the formula <FORM:0996489/C2/3> and an amino compound having the formula <FORM:0996489/C2/4> the radicals R1 to R4 being as defined above. In method (a) the reaction temperature may vary from 100 DEG  C. to the reflux temperature of the mixture (but not exceeding 300 DEG  C.) and is preferably from 130 DEG  to 220 DEG  C, and in method (b) the temperature may vary from 50 DEG  C. to the reflux temperature of the highest boiling reaction mixture (about 300 DEG  C.) and is preferably 80 DEG  to 135 DEG  C.  In both types of reaction it is preferred to use an excess of sulphur and elevated pressures may be used. A solvent may be present, e.g. when the phenol is not liquid at the reaction temperature or when using a lower-boiling amine.  Suitable solvents are higher-boiling glycol ethers and alcohols, dioxane and pyridine or in reaction (3) the amine reactant itself may also be used as solvent.  The residue formed on concentrating the mother liquor after recovering the desired products by solvent extraction or filtration is a viscous oily material having good antioxidant properties and the invention also includes such oily product per se.  Several examples are given and the hydroxythiobenzamide products have good antioxidant properties and for this purpose may be added to liquid hydrocarbon fuels, lubricant oils, functional fluids, greases, soaps, fats and oils (see Division C5) or to natural or synthetic rubber and synthetic polymers (see Division C3).  2,6 - Dialkyl - a  - morpholino - p - cresols are obtained by reacting a 2,6-dialkylphenol with morpholine and formaldehyde. 3,5-Dialkyl-4-hydroxybenzaldehydes are prepared by the dibromination of the p-methyl group of the corresponding 2,6-dialkyl-p-cresol in the presence of alcohol and then hydrolysing the dibrominated compound.ALSO:Hydroxythiobenzamides having the general formula <FORM:0996489/C3/1> wherein R1 and R2 are C1-C20 alkyl groups or C7-C20 aralkyl groups, R3 and R4 are alkyl, cycloalkyl, aralkyl, aryl, or alkaryl groups or are groups bonded together through an oxygen atom to form with the N atom depicted a morpholine ring (see Division C2) are used as antioxidants for synthetic polymers or rubbers such as polyethylene, polypropylene, polyisobutylene, polybutadiene, methyl rubber, polybutene rubber, natural rubber, butyl rubber, GR-S rubber, GR-N rubber, piperylene rubber and dimethyl butadiene rubber.  A specified rubber composition comprises pale crepe rubber and 3,5-di-tert-butyl-4-hydroxy-N,N-di-methyl thiobenzamide.ALSO:Hydroxythiobenzamides having the general formula <FORM:0996489/C4-C5/1> wherein R1 and R2 are C1-C20 alkyl groups or C7-C20 aralkyl groups, R3 and R4 are alkyl, cycloalkyl, aralkyl, aryl or alkaryl groups or R3 and R4 are groups bonded together through an oxygen atom to form with the N atom depicted a morpholine ring (see Division C2) are used as antioxidants in liquid hydrocarbon fuels, lubricating oils, functional fluids, greases, soaps, fats and oils of animal or vegetable origin and in petroleum wax, e.g. paraffin wax and microcrystalline wax.  The liquid hydrocarbon fuel may be gasoline, kerosine or fuel oil and the gasoline may contain an organo lead antiknock agent such as tetraethyl lead and in addition may contain a cyclopentadienyl manganese tricarbonyl or cyclopentadienyl nickel nitrosyl and, if desired, other additives such as halogen scavengers, e.g. ethylene dibromide and/or ethylene dichloride, phosphorus, arsenic and antimony compounds, dyes and solvents or diluents.  The lubricating oil may be a mineral oil or synthetic diester, e.g. sebacate or adipate and suitable functional fluids are paraffin base distillates, e.g. a Pennsylvania mineral oil (99 S.U.S. at 100 DEG  F.) which may also contain as additives: a polyacrylate of molecular weight about 7000 derived from cetyl or lauryl alcohol, a dimethyl silicone polymer anti-foam agent, a zinc dialkyl dithiophosphate and a barium petroleum sulphonate. Specified fats and oils which may be treated to improve their oxidative stability are linseed, cod liver, castor, soy bean, rape seed, coconut, olive, palm, corn, sesame, peanut and babassu oils, butter fat, lard, and beef tallow.