反应 #722593

反应方程式

mono(3,4-dimethylbenzylidene)-D-xylitol

D-xylitol

3,4-dimethylbenzaldehyde

sulfuric acid

→

bis(3,4-dimethylbenzylidene)-D-xylitol

收率 0.5%

反应条件

后处理

1. 1
   其他The obtained reaction mixture

实验过程

A 500 ml four-necked flask was charged with a 70 wt % aqueous solution of 120 g (0.55 mole) of D-xylitol, 73.7 g (0.55 mole) of 3,4-dimethylbenzaldehyde and 12 g of 50 wt % sulfuric acid. The air inside the system was replaced with nitrogen gas. The contents of the flask were stirred at a temperature of 21° C. for 6 hours. The obtained reaction mixture was analyzed by GC. It was found that mono(3,4-dimethylbenzylidene)-D-xylitol was produced in a yield of 70% and 0.5% or less of bis(3,4-dimethylbenzylidene)-D-xylitol was also produced. After standing 24 hours, the reaction mixture was neutralized for 2 hours using 8.6 g of potassium hydroxide, and filtered to obtain cake. The cake was dispersed in 150 ml of toluene and was filtered again. After drying at 100° C. under a pressure ranging from normal pressure to 5 mmHg for 7 hours, 44.5 g of 2,4-O-(3,4-dimethylbenzylidene)-D-xylitol was obtained with a purity of 99.2% as measured by GC (yield 30.1%). The product had a melting point of 179.5 to 180.0° C.

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