Process for the preparing bromoisophithalic acid compound
AssigneeNissan Chemical Industries, Ltd.
InventorsMasaki Nagai, Hideo Suzuki, Isao Hashiba
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Abstract
The present invention relates to a process for preparing bromoisophthalic acid compounds, particularly 5-bromoisophthalic acid compounds and 4,5-dibromoisophthalic acid compounds comprising brominating an isophthalic acid compound of the general formula (1) wherein R1 and R2 independently of one another are hydrogen atom or C1-6 alkyl, with bromine in a solvent containing sulfur trioxide. The object of the invention is to provide a process for preparing bromoisophthalic acid compounds, particularly 5-bromoisophthalic acid compounds and 4,5-dibromoisophthalic acid compounds in a highly selective manner by using bromine that is industrially inexpensive.
Claims4
A process for preparing 5-bromoisophthalic acid compound comprising brominating an isophthalic acid compound of the general formula (1)
- wherein R1 and R2 independently of one another are hydrogen atom or C1-6 alkyl, with bromine in fuming sulfuric acid containing sulfur trioxide in a concentration of 1 to 30 wt % at a reaction temperature between 100° and 160° C.
A process for preparing 5-bromoisophthalic acid diester compound comprising the steps of:
- brominating an isophthalic acid compound of the general formula (1)
- wherein R1 and R2 independently of one another are hydrogen atom or C1-6 alkyl, with bromine in a molar amount 0.5 to 1.5 times that of the isophthalic acid compound in fuming sulfuric acid containing sulfur trioxide in a concentration of 1 to 30 wt % at a reaction temperature between 100° C. and 160° C. to produce a crude product;
- diesterifying the resulting crude product with a lower alcohol with 1 to 5 carbon atoms at the presence of an acid catalyst to a diesterified compound;
- and
- then separating and purifying the diesterified compound by distillation.
Dependencies are inferred from the claim text.