申请人:Ciba Specialty Chemicals Holding Inc.
公开号:EP0959059A2
公开(公告)日:1999-11-24
The invention pertains to a process for inhibiting the premature polymerization of a vinyl aromatic compound during distillation or purification which comprises incorporating therein a stable cyclic hindered nitroxyl compound used together with oxygen or air to enhance the inhibiting activity of the nitroxyl compound, with the proviso that no nitro-aromatic compound is present and the cyclic hindered nitroxyl compound is not (2-butyl-3-(1-oxyl-2,2,6,6-tetramethyl-piperidine-4-yloxycarbonylamino)-phenyl)-carbamic acid 1 -oxyl-2-2,2,6,6-tetramethyl-piperidine-4-yl ester or (6-(1-oxyl-2,2,6,6-tetramethyl-piperidine-4-yloxycarbonylamino)hexyl)-carbamic acid 1-oxyl-2,2,6,6-tetramethyl-piperidine-4-yl-ester.
本发明涉及一种在蒸馏或提纯过程中抑制乙烯基芳香族化合物过早聚合的工艺,该工艺包括在其中加入一种稳定的环状受阻亚硝基化合物,与氧气或空气一起使用,以增强亚硝基化合物的抑制活性、条件是不含硝基芳香族化合物,且环状受阻亚硝基化合物不是(2-丁基-3-(1-氧代-2,2,6,6-四甲基-哌啶-4-基氧羰基氨基)-苯基)-氨基甲酸 1-氧代-2、2,2,6,6-四甲基-哌啶-4-基酯或(6-(1-氧代-2,2,6,6-四甲基-哌啶-4-基氧基羰基氨基)己基)-氨基甲酸 1-氧代-2,2,6,6-四甲基-哌啶-4-基酯。