Process for preparing 4-substituted 2,2,6,6-tetramethylpiperidin-N-oxy and 2,2,6,6-tetramethylpiperidin-N-hydroxy compounds
申请人:Osterholt Clemens
公开号:US20050256312A1
公开(公告)日:2005-11-17
A process for preparing 4-substituted 2,2,6,6-tetramethylpiperidin-N-oxy compounds (II) or mixtures of (II) and 4-substituted 2,2,6,6-tetramethylpiperidin-N-hydroxy compounds (III)
where X+Y can be O or can represent a cyclic ketal with the radicals
or can represent an open-chain ketal in which X═O—R and Y═O—R′, where R and R′ can be identical or different and can each be CH
3
, CH
2
—CH
3
, CH
2
—CH
2
—CH
3
, CH(CH
3
)—CH
3
, CH
2
—CH
2
—CH
2
—CH
3
and CH
2
—CH(CH
3
)—CH
3
,
by oxidizing corresponding 4-substituted 2,2,6,6-tetramethylpiperidines (I)
with hydrogen peroxide in the presence of alkali metal hydrogencarbonate and/or ammonium hydrogencarbonate and in the presence or absence of a solvent, in which the reaction is carried out with the addition of Brönsted acids which have an acid strength greater than that of the hydrogencarbonate.
一种制备4-取代的2,2,6,6-四甲基哌啶-N-氧化物化合物(II)或(II)和4-取代的2,2,6,6-四甲基哌啶-N-羟基化合物(III)或(II)和(III)混合物的方法,其中X+Y可以是O,也可以表示具有基团的环状酮缩物,或者可以表示X═O—R和Y═O—R′的开链酮缩物,其中R和R′可以相同也可以不同,且每个可以是CH3、CH2—CH3、CH2—CH2—CH3、CH(CH3)—CH3、CH2—CH2—CH2—CH3和CH2—CH(CH3)—CH3,通过在碱金属碳酸氢盐和/或氢碳酸铵存在下氧化相应的4-取代的2,2,6,6-四甲基哌啶(I)与过氧化氢反应,反应可以在溶剂的存在或缺席下进行,并在添加酸强度大于碳酸氢盐的Brönsted酸的情况下进行。