Method for synthesizing 3,4-dihydroxy benzaldehyde by using air catalytic oxidation
A technology of dihydroxybenzaldehyde and catalytic oxidation, which is applied in chemical instruments and methods, preparation of organic compounds, preparation of carbon-based compounds, etc., can solve the problems of difficult recovery, large dosage, increased production cost, etc., and achieves reduction of production cost, Easy to recycle and reuse the effect
Active Publication Date: 2012-07-18
PETROCHINA CO LTD
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Wang Junhua is in " 3, the production technology of 4-dihydroxybenzaldehyde (CN02158203) ", catechol and glyoxylic acid are carried out condensation reaction under the action of sodium hydroxide to generate 3, 4-dihydroxymandelic acid, then The generated 3,4-dihydroxymandelic acid and compound copper salt carry out oxidative decarboxylation reaction to generate 3,4-dihydroxybenzaldehyde. In the oxidative decarboxylation reaction stage in this process, the compound copper salt is used alone as the oxidizing agent. It is very large, and it is difficult to recycle, which greatly increases the production cost
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Embodiment 1
[0022] Add accurately weighed 3,4-dihydroxymandelic acid into a reactor equipped with a stirrer, a thermometer, and a reflux device, and add dropwise 30% aqueous sodium hydroxide solution under stirring so that the pH value of the solution is weakly alkaline, and then A catalyst was added (the molar ratio of catalyst to 3,4-dihydroxymandelic acid was 0.02), the temperature was raised to 90° C., air was introduced, and the reaction was carried out under these conditions for 7 hours. After the reaction finishes, take a sample and analyze the yield of 3,4-dihydroxybenzaldehyde, and the test results are shown in the attached table.
Embodiment 2
[0024] According to the operation steps of embodiment 1, adopting respectively to add catalyst and 3, the mol ratio of 4-dihydroxymandelic acid is 0.03,0.04,0.05, and all the other processing conditions remain unchanged with embodiment 1, test result sees attached table.
Embodiment 3
[0026] According to the operating steps of embodiment 1, except changing the reaction time, all the other processing conditions are identical with embodiment 1, and test result sees the attached table below.
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The invention relates to a method for synthesizing 3,4-dihydroxy benzaldehyde by using air catalytic oxidation, comprising the following steps: carrying out condensation reaction on pyrocatechin and glyoxylic acid at alkali condition to obtain 3,4-dihydroxymandelic acid, separating the 3,4-dihydroxymandelic acid to obtain a pure product, weighing the pure product accurately after drying, dissolving the pure product into water, adjusting the pH value to alkalescence by alkaline aqueous solution, adding catalyzer, introducing air and carrying out oxidation reaction under the condition of heating and stirring to obtain the 3,4-dihydroxy benzaldehyde, wherein, the catalyzer is composite type metallic oxide with multicomponents, the mole ratio of the catalyzer and the 3,4-dihydroxymandelic acid is 0.02-0.05, the temperature is 85-95 DEG C, the air flow is 80-110L / h, the yield of the 3,4-dihydroxy benzaldehyde is 72.3-90.7%, and the catalyzer is easy to be recycled and reused and is suitable for large scale production of 3,4-dihydroxy benzaldehyde.
Description
Technical field: [0001] The invention relates to a method for synthesizing 3,4-dihydroxybenzaldehyde through air catalytic oxidation decarboxylation reaction using 3,4-dihydroxymandelic acid produced by the condensation reaction of catechol and glyoxylic acid as a raw material. Background technique: [0002] 3,4-Dihydroxybenzaldehyde is an important raw material for organic synthesis and a pharmaceutical intermediate. It was originally an active ingredient extracted and separated from traditional Chinese medicines such as the Ilex plant Sijiqing and the Salvia genus Salvia. An antibiotic and anti-inflammatory drug, it is the key raw material of anti-inflammatory drug Anoretic and its derivatives, new cephalosporin antibiotic Cephalosporin, and semi-synthetic antibiotic Anti iarone-F. It can also be used to synthesize anti-shock vasoactive drugs dopamine hydrochloride, adrenal and norepinephrine hormones. [0003] According to literature reports, in the synthesis of 3,4-dihy...
Claims
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IPC IPC(8): C07C47/565C07C45/51
CPCY02P20/584
Inventor 李耀先魏国峰杨清彪王硕刘宇刘福安张锁秦王恒国梁小飞
Owner PETROCHINA CO LTD