Preparation method of D-(-)-formyl mandelate chloride
A technology of formyl mandelic acid and formyl mandelic acid is applied in the preparation field of D--O-formyl mandelic acid chloride, can solve the problems such as inability to apply mechanically, waste of raw material formic acid, and no cost saving, and achieves easy operation, The effect of saving formic acid and easy absorption
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Embodiment 1
[0033] Table 1 Synthesis of formylmandelic acid feed ratio
[0034]
[0035] Add 300 g of D-mandelic acid, 100 g of formic acid, and 300 g of methylene chloride into a 2000 ml four-necked bottle, and stir at room temperature for half an hour to dissolve it.
[0036] After dissolving, add 5g of activated carbon, lower the temperature to 0-10°C, then add a mixed solution of 195g of solid light and 300g of dichloromethane dropwise, at a temperature of 0-10°C, during which hydrogen chloride gas is precipitated, and the dropping time is 3h.
[0037] After the dropwise addition, keep the temperature at 10-20°C for 5 hours, filter the activated carbon, and recover dichloromethane and excess formic acid under normal pressure. 350-360 g of colorless viscous D(-) formylmandelic acid liquid was obtained.
Embodiment 2
[0039] Table 2 synthesis of D-formyl mandelic acid chloride feed ratio
[0040]
[0041] Put the D(-)formylmandelic acid crude product obtained in the first step of distillation into a 2000ml four-necked bottle, then add 300g of dichloromethane and 5g of activated carbon into the four-necked bottle, and dropwise add 220g of solid light at 10-20°C The dichloromethane solution was added dropwise for 5 hours, and hydrogen chloride gas was precipitated in the middle. After the dropwise addition, keep the temperature at 15-20° C. for 1 hour, and slowly raise the temperature to reflux. After refluxing for 5 hours, cool down and filter out the activated carbon, recover dichloromethane, and then place the residue under a mechanical pump and distill the product under a 1mHg vacuum to obtain a colorless and transparent D(-)formylmandelic acid chloride. The obtained D(-)formylmandelic acid chloride is 380-390g, the detection content is more than 99%, ee99%.
Embodiment 3
[0043] Put 300 g (1.97 mol) of D-mandelic acid, 100 g (2.17 mol) of formic acid, and 300 g of methylene chloride into a 2000 ml four-necked bottle, and stir at room temperature for half an hour to dissolve it.
[0044] After dissolving, add 5 g of activated carbon, lower the temperature to 0-10° C., and then add the dichloromethane solution of solid light dropwise into the solution. The amount of solid light added is shown in Table 3. The dropping temperature is 0-10°C, and hydrogen chloride gas is precipitated in between, and the dropping time is 3 hours.
[0045] After the dropwise addition, keep the temperature at 10-20°C for 5 hours, filter the activated carbon, and recover dichloromethane and excess formic acid under normal pressure. A colorless viscous D(-)formylmandelic acid liquid was obtained.
[0046]It is calculated that when the amount of solid light added is 1.2mol, 1mol, 0.6mol, 0.4mol respectively, the conversion rate of D-mandelic acid reaches 99.9%, 99.9%, 99...
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