Patent ID: 8404161

Claim:
A hydroxyphenyl or alkoxyphenyl phosphine oxide composition comprising: (i) from about 10 to about 50 wt % of a first mixture of mono-(hydroxyphenyl) or (alkoxyphenyl) phosphine oxide isomers each having the formula (I): (ii) from about 30 to about 60 wt % of a second mixture of bis-(hydroxyphenyl) or (alkoxyphenyl) phosphine oxide isomers each having the formula (II): (iii) from about 10 to about 50 wt % of a third mixture of tris-(hydroxyphenyl) or (alkoxyphenyl) phosphine oxide isomers each having the formula (III): iv) 0 to 10 mol % of triphenyl phosphine oxides of the formula IV: wherein R is hydrogen or an alkyl group containing from 1 to 6 carbon atoms, R 1 and R 2 are the same or different and each is an alkyl group containing from 1 to 6 carbon atoms, each of x and y is an integer from 0 through 4, and each OR group is in the ortho or para position with respect to the bond between the P atom and the associated phenyl group such that, for each mixture (i), (ii) and (iii), the ratio of the number of OR groups in the ortho-position with respect to the bond between the P atom and the associated phenyl group to the number of OR groups in the para-position with respect to the bond between the P atom and the associated phenyl group is from about 20:80 to about 1:99.