Alkyl arylphosphinites

A process for the preparation of an alkyl arylphosphinite of the formula (I) ##STR6## in which R.sup.1 is (C.sub.1 -C.sub.16)-alkyl, cyclohexyl, cyclopentyl, aryl which can also be substituted by halogen, (C.sub.1 -C.sub.6)-alkoxy groups,

• R.sup.2 is aryl which can also be substituted by halogen, (C.sub.1 -C.sub.6)-alkyl, (C.sub.1 -C.sub.6)-alkoxy groups, where R.sup.1 and R.sup.2 together with the phosphorous atom can also form a ring, and
• R.sup.3 is (C.sub.1 -C.sub.4)-alkyl, which comprises reacting a halo(aryl)phosphine of the formula (II) ##STR7## in which R.sup.1, R.sup.2 have the meaning given above and X is halogen, by adding the phosphine to an alcohol of the formula (III)
• R.sup.3 OH (III)
• in which R.sup.3 has the meaning given above, wherein the alcohol is present in excess based on the phosphine and said reacting step produces a hydrohalide byproduct, and wherein a neutralizing agent is present in solution in said alcohol prior to the formation of said hydrohalide byproduct, said neutralizing agent consisting essentially of ammonia.