Patent GB-1035985-A (GB)
Title: New hydroxy phenyl bis thiazoles and their use as stabilisers
IPC: F02B3/06
Filed: 1963-05-03
Abstract: Organic compounds for example polymers, lubricant oils, mineral oils, animal oils, vegetable oils, fatty materials, hydrocarbons and aldehydes are stabilized against deterioration by incorporating therein at least 0.001% by weight of a compound of the general formula <FORM:1035985/C4-C5/1> wherein R1 is an alkyl radical, preferably a C1 to C6 alkyl radical, R2 is hydrogen or an alkyl group, preferably a C1 to C6 alkyl group, R3 is hydrogen or a C1 to C6 alkyl group and A is a direct linkage or a methylene group, especially the compound wherein R2 is a tertiary butyl group, and most preferably wherein R2 is a tertiary butyl group in the position ortho to the hydroxyl on the phenyl nucleus.  The most preferred stabilizers are the compounds 2,21 - bis[41 - (3,5 - di - t - butyl - 4 - hydroxyphenyl) thiazole] and 2,21 - methylene - bis-[41 - (3,5 - di - t - butyl - 4 - hydroxyphenyl) thiazole] the most preferred embodiment is wherein the organic material stabilized is polypropylene, which forms the subject of the example.  The Specification makes reference to stabilizing lubricating oils of the mineral type as well as the aliphatic esters for example dihexyl azelate, di-(2-ethylhexyl-azelate, di-(3,5,5-trimethylhexyl) glutarate, di-(3,5,5-trimethylpentyl)-glutarate, di-(2-ethylhexyl) pimelate, di-(2-ethylhexyl) adipate, diisoamyl adipate, triamyl tricarballylate, pentaerythritol tetracaproate, dipropylene glycol dipelargonate, 1,5-pentanediol-di-(2-ethylhexanoate), and the stabilizers may also be used in conjunction with the following named edible fats and oils: linseed oil, menhaden oil, cod liver oil, castor oil, olive oil, rapeseed oil, coconut oil, palm oil, corn oil, sesame oil, peanut oil, cotton seed oil, butter, fat, lard, beef tallow.  Saturated and unsaturated hydrocarbons for example gasolines, fuel oils, jet fuel, diesel oil, may also be stabilized by using the bis thiazoles.  Named polymers capable of being stabilized include high impact polystyrene containing copolymers of butadiene and styrene such compositions may contain further additive agents for example, antioxidants, pourpoint depressants, corrosion and rust inhibitors, dispersing agents, demulsifiers, antifoaming agents, carbon black, accelerators, plasticizers, colour stabilizers, heat stabilizers, UV absorbers, dyes, pigments and fillers.ALSO:The invention comprises hydroxyphenyl-bisthiazoles of the formula <FORM:1035985/C2/1> wherein R1 is an alkyl group, especially a C1 to C6 alkyl, R2 is hydrogen or a C1 to C6 alkyl group, especially a tertiary butyl group, particularly ortho to the phenolic hydroxyl, R3 is hydrogen or a C1 to C6 alkyl group, particurlarly hydrogen, and in particular the compounds 2,21-bis - [41 - (3,5 - di - t - butyl - 4 - hydroxyphenyl) - thiazole] and 2,21 - methylene - bis[41 - (3,5 - di - t - butyl - 4 - hydroxyphenyl)-thiazole], which are added to organic materials (see Division C5) and e.g. heptaldehyde as stabilizers.  The compounds may be prepared by the reaction of the appropriately substituted haloacetyl phenol with dithio-oxamide, as e.g. in Example 1, wherein 4-o -bromo-acetyl-2,6 - di - t - butylphenol and dithio-oxamide give 2,21 - bis - [41 - (3,5 - di - t - butyl - 4 - hydroxyphenyl)-thiazole], or the corresponding 2-methyl or 2-dodecyl phenols give the 3-methyl and 3-dodecyl-4-hydroxyphenyl compounds. Alternatively, the use of dithiocarboxylic acid amide as e.g. in Example 2, dithiomalonamide, gives with a  - bromo - 4 - acetyl - 2,6 - di - t - butylphenol.  2,21 - Methylene - bis - [41 - (3,5di - t - butyl - 4 - hydroxyphenyl) - thiazole]. By using 2,6-dimethylphenol or 2-t-octylphenol, the corresponding 3,5-dimethyl and 3-t-octyl compounds can be obtained.ALSO:Polymers, especially polypropylene, are stabilized by the addition thereto of at least 0.001% of a compound of the general formula <FORM:1035985/C3/1> wherein R1 is an alkyl group, preferably C1 to C6, R2 is hydrogen or alkyl, preferably C1 to C6, R3 is hydrogen or a C1 to C6 alkyl group, and A is a direct link or a methylene group especially the compound wherein R2 is tertbutyl and especially ortho to the phenolic hydroxyl group.  The most preferred compounds are 2,21-bis[41-(3,5-di-t-butyl-4-hydroxy phenol)thiazole] and 2,21-methylene-bis-[41-(3,5-di - t - butyl - 4 - hydroxyphenyl)thiazole]. Compounds of the general formula wherein R1, R2, R3 and A respectively are H, Me, H, link; H, dodecyl, H, link; Me, Me, H, -CH2-; H, t-octyl, H, -CH2 are mentioned in the description.  The usual additives may be present in the compositions, e.g. carbon black, which base material may also be polyethylene, high impact polystyrene.