申请人:Kawasaki Steel Corporation
公开号:US05072036A1
公开(公告)日:1991-12-10
Para-hydroxybenzoic acid is prepared by reacting an alkali metal salt of phenol except the lithium and sodium salts with carbon dioxide in the presence of at least one compound selected from compounds of the following formulae (I) and (II): ##STR1## In formulae (I) and (II), M is an alkali metal except lithium and sodium; R is any substituent except an aliphatic hydroxy group having up to 4 carbon atoms, an aliphatic mercapto group having up to 4 carbon atoms, a substituent having at least one of them as its structural unit, and a hydrogen atom; R' is any substituent except an aliphatic hydroxy group having up to 4 carbon atoms, an aliphatic mercapto group having up to 4 carbon atoms, and a substituent having at least one of them as its structural unit; in formula (I) n is an integer of 1 to 5, and R groups may be the same or different when n is more than one; in formula (II) m is an integer of 1 to 5 and l is an integer of 0 to 4, and M alkali metals may be the same or different when m is one or more, and R' groups may be the same or different when l is more than one. The reaction may be carried out in the presence or absence of reaction medium.
对苯二酚的除锂和钠盐外的碱金属盐,与二氧化碳在以下式(I)和(II)化合物中至少选择一种存在的情况下,反应制备对羟基苯甲酸:##STR1##
在式(I)和(II)中,M为除锂和钠之外的碱金属;R为任何取代基,但不包括具有最多4个碳原子的脂肪族羟基基团,最多4个碳原子的脂肪族巯基基团,至少包含其中之一作为其结构单元的取代基和氢原子;R'为任何取代基,但不包括具有最多4个碳原子的脂肪族羟基基团,最多4个碳原子的脂肪族巯基基团和至少包含其中之一作为其结构单元的取代基;在式(I)中,n为1至5的整数,当n大于1时,R基团可以相同或不同;在式(II)中,m为1至5的整数,l为0至4的整数,当m为1或更多时,M碱金属可以相同或不同,当l大于1时,R'基团可以相同或不同。反应可以在反应介质的存在或缺席下进行。