Abstract: A compound of the formula, wherein R.sub.1 is hydrogen or a halogen atom, R.sub.2 is ##STR1## R.sub.3 is hydrogen, an alkyl group, a cycloalkyl group or an aralkyl group, and n is an integer of 1 or 2, which is useful as ultraviolet absorber.

Abstract: A ultraviolet of absorber containing 2-(2',4'-dihydroxyphenyl)-5-chlorobenzotriazole is effectively used to stabilize polyurethane resins against ultraviolet rays.

Abstract: A process for the production of an octyltin chloride of the formula,(n-C.sub.8 H.sub.17).sub.m SnCl.sub.4.sub.-mWherein m is an integer of 1 to 3, which comprises reacting n-octyl chloride with metallic tin in an organic solvent in the presence of (1) either a mixture of a phosphorus compound with an amine, or a phosphorus compound having a nitrogen atom in the molecule, and (2) at least one of bromine, a bromine compound, iodine and an iodine compound. The octyltin chlorides are useful for the production of stabilizers for polyvinyl chloride.