| 摘要 |
Prepn. of a hydroxybenzoic acid ester by trans-esterification comprises reacting a hydroxybenzoic acid ester with a prim. or sec. alcohol having at least one hydrogen atom on the carbon atom in the alpha -position w.r.t the hydroxy-bearing carbon atom. The reaction is carried out in the presence of a titanium-based catalyst which is soluble in the reaction mixt. The above catalyst is claimed per se. The Titanium catalyst is prepd. in situ by reacting a salt of an inorganic acid (e.g. TiCl4) with an alcohol, phenol, ether-alcohol or alkanolamine. It is pref. an alkoyl or aryl ortho-titanate or the titanate of mono-, di- or tri-ethanolamine. The alcohol is of formula R1OH, where R1 e.g. a 2-40C alkyl, alkenyl or alkadienyl (opt. interrupted by a hetero-atom or a gp. such as CO or COO). Alternatively it may be 3-8C monocycle opt. having 1-2 unsaturations in the ring or it may be polycyclic, pref. bicyclic e.g. bicyclo4.1.0heptanyl. The ester is a phenol substd. by a lower(1-4C)alcohol residue, pref. Me or Et.
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