Patent ID: 6267844
Filing Date: 2001-07-31
Classification: C07C,C07D,D21H

Abstract:
A process for reducing brightness reversion in a paper production process, comprising the process steps of (a) providing a paper pulp, and (b) forming a paper sheet therefrom, the process further including the process step of contacting the paper sheet at some point in the said production process with a compound of formula I: ##STR17##in whichm is an integer of from 2-4;n is an integer of at least 2;p is an integer of from 1-4;X is --C(.dbd.O)--, --CH.sub.2 C(.dbd.O)O--, --C(.dbd.O)NH--, --S(.dbd.O).sub.2 -- or a direct bond, and A is alkylene or arylene;R.sub.1 is (a) alkyl (C.sub.1 -C.sub.6), (b) phenyl or benzyl, or (c) a heteroaromatic residue, and if p is equal to 1 and R.sub.2 is hydrogen or alkyl (C.sub.1 -C.sub.6), then R.sub.1 can also be another residue R.sub.3 O[(CH.sub.2).sub.m O].sub.n X--A--S--Z-- where R.sub.3 is hydrogen or alkyl (C.sub.1 -C.sub.6), and Z is selected from (CH.sub.2).sub.2, (CH.sub.2).sub.3, (CH.sub.2).sub.4, CH.sub.2 CH(CH.sub.2 OH), CH.sub.2 CH(OH)CH(OH)CH.sub.2, CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2, 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 2,5-(1,3,4-thiadiazolyl), 1,3-xylylene, 1,3,5-triazinyl (optionally substituted), andR.sub.2 is hydrogen or alkyl (C.sub.1 -C.sub.6), or another residue R.sub.1 --S--A--X--; wherein the paper sheet, after contact with the compound of formula I, has a reduced tendency to undergo brightness reversion.