Patent GB-580845-A (GB)
Title: Improvements in or relating to corrosion preventing compositions
IPC: C09D5/08
Filed: 1943-02-13
Abstract: A coating composition for protecting metals against corrosion comprises a saponifiable fatty material, a hydrocarbon oil and a small proportion of a substance obtained by alkylating p-cresol, in the presence of an alkylation catalyst, with a reagent which will introduce a tertiary aliphatic radicle, such as tertiary butyl, amyl or hexyl, into the cresol molecule.  Suitable alkylating agents are tertiary olefins or alcohols such as isobutene or tertiary butyl alcohol, while the alkylation catalyst may be sulphuric acid.  The saponifiable material may be woolfat, fatty acids or esters thereof, fatty oils, or fatty residues such as cottonseed pitch, linseed oil distillation residues, stearine pitch or distillation residues of oxidised petroleum hydrocarbons. The hydrocarbon oil may be a petroleum lubricating oil or a synthetic oil and may be blended with petroleum waxes, petrolatums and polybutene polymers.  The coating composition may also contain alcohols, soaps of mahogany, fatty or naphthenic acids, waxes, petrolatums, linear polymer thickeners. pour inhibitors, dyes, metal passifying agents such as amine-aldehyde condensation products or ammonia-methylene chloride-alkylated phenol condensation products and resins.  In examples, the coating compositions comprise (1) hydrocarbon lubricating oil, woolfat, alkali mahogany soaps and the tertiary butyl alkylation product of p-cresol, (2) hydrocarbon transformer oil, woolfat, alkali mahogany soaps and the tertiary butyl alkylation product of p-cresol.  The Specification as open to inspection under Sect. 91 describes also a coating composition comprising a saponifiable fatty material, a hydrocarbon oil or a mahogany soap, and a compound of the formula RnArOR1 where Ar is an aromatic nucleus, R is an organic radicle forming a substituent in the aromatic nucleus, R1 is a tertiary aliphatic radicle, and n is an integer. When more than one radicle R is present, they may be alike or different.  One or more of the hydrogen atoms of the aromatic nucleus or of the radicles R and R1 may be replaced by substituent atoms or groups and a large number of suitable substituents are specified.  A long list of substances having the general formula mentioned above is given and it is stated that the product obtained by alkylating p-cresol with a reagent which will introduce a tertiary butyl radicle into the cresol molecule is the tertiary butyl ether of ortho tertiary butyl p-cresol.  Other antioxidants or anti-corrosion agents which may be present in the coating composition are amines such as diethyl amino ethanol, 2-amino-2 methyl-1-propanol, phenylethanol amine or the reaction products of ammonia and alkylated phenol formaldehyde or phenol methylene chloride.  The addition of phenyl ethanolamine to the composition of example (2) is mentioned.  This subject-matter does not appear in the Specification as accepted.ALSO:Ethers of p-cresol are obtained by alkylating p-cresol, in the presence of an alkylation catalyst, with a reagent which will introduce a tertiary aliphatic radicle, such as tertiary butyl, amyl or hexyl, into the cresol molecule.  Suitable alkylating agents are tertiary olefins or alcohols such as isobutene or tertiary butyl alcohol, while the alkylation catalyst may be sulphuric acid.  In an example, isobutene is bubbled into a heated mixture of p-cresol and sulphuric acid, the reaction mixture is blown with steam and washed with hot water and dilute alkali until neutral.  The same product may be obtained by reacting p-cresol with tertiary butyl alcohol at 0-50 DEG  C., but in this case the amount of sulphuric acid catalyst is preferably quite large.