Process for preparing protocatechualdehyde and its derivatives
AssigneeUbe Industries, Ltd.
InventorsSumio Umemura, Nagaaki Takamitsu, Takuji Enomiya, Hiroshi Shiraishi, Takato Nakamura
Life of this patent
Estimating the term…
Abstract
A process for preparing protocatechualdehyde or a 3-alkoxy-4-hydroxybenzaldehyde which comprises subjecting catechol or a 2-alkoxyphenol to reaction with glyoxylic acid in a basic aqueous medium in the presence of a catalyst containing one or more compounds selected from aluminium oxide, silicon oxide and hydrated aluminium oxide in an amount of not less than 0.01 g per 1 g of the starting catechol or 2-alkoxyphenol at a temperature of 0.degree. to 50.degree. C., and then oxidizing the thus obtained reaction mixture in a basic medium.
Claims8
An improved process for preparing protocatechualdehyde or a 3-alkoxy-4-hydroxybenzaldehyde represented by the formula ##STR3## wherein R represents a methyl group or an ethyl group, which comprises reacting catechol or a 2-alkoxyphenol represented by the formula ##STR4## with glyoxylic acid in a basic aqueous medium to form a reaction product, and then oxidizing said reaction product in a basic aqueous medium,
- the improvement comprising reacting said catechol or said 2-alkoxyphenol with glyoxylic acid in the range of 0.5-2 moles per mole of catechol or a 2-alkoxyphenol, in an aqueous medium containing a strong inorganic base and at least one catalyst selected from the group consisting of aluminum oxide, silicon oxide and hydrated aluminum oxide in an amount of not less than 0.01 g. per 1 g. of the starting catechol or 2-alkoxyphenol at a temperature of 0.degree. to 50.degree. C. to form said reaction product.
Dependencies are inferred from the claim text.