Para-hydroxy-benzoic acid phenyl esters - useful for stabilisation of organic materials against UV light

摘要

Title esters have the formula (I) (where n=1-4; R1=4-14C tert. alkyl gp; R2=H, 1-20C alkyl or alkoxy, phenyl gp. opt. substd. by 1 or 2 1-6C alkyl, or a cycloalkyl, alkylcycloalkyl cycloalkyl alkyl or aralkyl gp. of =12C the aryl part of the latter being opt. substd. by 1 or 2 1-6C lkyl gps. or 1 or 2 halogen atoms; R3 and R4 are each H or 1-8C alkyl; X=O, S or -NR5- in which R5=H. 1-20C alkyl, phenyl, cycloalkyl, alkylcycloalkyl, cycloalkyl or aralkyl contg. =12C atoms and X's may be different when n=2-4; R=aliphatic hydrocarbon, cycloaliphatic or araliphatic gp. of valency n, satd. or unsatd. contg. =22C whose aliphatic chain is opt. substd. by a halogen atom, CN or carboxy gp. or is interrupted by -O-, -S-, -SO2-, -CO-, -COO- and/or -COS-, the aryl part is opt. substd. by 1 or 2 1-6C alkyl gps. and/or a OH gp, or R is a 6-13C aromatic gp. opt. substd. with the substs. having =18C and the gp.=24C, the alkyl gp. in R has >=4C atoms when R3 and R4 are each H atoms).