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A technology of methyl catechol and methyl phthalate is applied in the field of preparation of 4-methyl catechol, and achieves the effects of high yield, saving time and cost, and reducing production cost
Inactive Publication Date: 2014-02-12
ZHEJIANG SCI-TECH UNIV
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[0005] In summary, there is currently no suitable method to produce 4-methylcatechol cheaply, safely and environmentally friendly
Method used
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Embodiment 1
[0028] Add o-phthalylene dimethyl ether (69g, 0.5mol), paraformaldehyde (15.75g, 0.525mol) and 100ml dichloroethane into the reaction flask, drop the temperature to -5~10°C, and slowly add concentrated hydrochloric acid ( 50ml, 0.6mol), then reacted at this temperature for 5 hours, filtered after the reaction, and the filtrate was separated into the water layer, and the dichloroethane layer was washed once with water, then washed once with saturated aqueous sodium bicarbonate solution, and finally washed once again with water , dried over sodium sulfate, and concentrated to obtain a crude product, which was then distilled under reduced pressure to obtain 69.9 g of 4-chloromethyl-phthalene dimethyl ether, with a yield of 75%.
Embodiment 2
[0030] Add o-phthalylene dimethyl ether (69g, 0.5mol), paraformaldehyde (30g, 1mol) and 100ml of dichloromethane into the reaction flask, drop the temperature to -5~10°C, and slowly add concentrated hydrochloric acid (100ml, 1.2 mol), and then reacted at this temperature for 3-4 hours, filtered after the reaction, and the filtrate was separated into the water layer. After the sodium was dried, it was concentrated to obtain a crude product, which was then distilled under reduced pressure to obtain 65.3 g of 4-chloromethyl-phthalamide, with a yield of 70%.
Embodiment 3
[0032] Add o-phthalylene dimethyl ether (69g, 0.5mol), paraformaldehyde (75g, 0.525mol) and 100ml chloroform into the reaction flask, drop the temperature to -5~10°C, slowly add concentrated hydrochloric acid (208ml, 2.5mol ), then reacted at this temperature for 3 hours, filtered after the reaction, and the filtrate was separated into the water layer. The chloroform layer was washed once with water, then washed once with saturated aqueous sodium bicarbonate solution, and finally washed once with water, dried over sodium sulfate, and concentrated The crude product was obtained, and then 17 g of 4-chloromethyl-phthalyl ether was obtained by distillation under reduced pressure, with a yield of 18.3%.
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Abstract
The invention discloses a preparation method of 4-methylcatechol. The method comprises the following steps: (a) adding dimethoxybenzene and paraformaldehyde to an organic solvent, dropwise adding concentrated hydrochloric acid at minus 5 to 10 DEG C, so as to obtain 4-chloromethyl dimethoxybenzene; (b) firstly, adding the 4-chloromethyl dimethoxybenzene to an alcohol solvent, adding zinc powder and ammonium salt, heating and refluxing to generate the 4-chloromethyl dimethoxybenzene in a reduction manner; (c) mixing the 4-chloromethyl dimethoxybenzene, a hydrogen bromide aqueous solution and/or added cosolvent, warming and refluxing to obtain 4-methylcatechol. By adopting the method, the dimethoxybenzene is taken as a raw material; 4-methylcatechol is synthetized by three steps of chloromethylation, reduction and demethylation. The method has the characteristics of being high in yield, simple in steps, available in raw materials, mild in reaction condition, fewer in three wastes, low in production cost, simple in post-treatment and the like, and has good industrial application prospect.
Description
technical field [0001] The invention relates to a preparation method of 4-methylcatechol. Background technique [0002] 4-Methylcatechol is an important organic chemical raw material, which can be used as an intermediate in the synthesis of spices, medicines, pesticides and dyes, and can also be used as an antioxidant for food and a high-efficiency polymerization inhibitor for polymer polymerization . Due to the wide application of this compound, many scholars have studied its synthetic route. The synthesis methods reported in the comprehensive literature mainly contain the following: [0003] The first method is to use p-cresol as a raw material and synthesize it in one step by oxidation with different concentrations of hydrogen peroxide under different conditions. For example, Chinese patent CN1298857A reported that 4-methylcatechol was synthesized by hydroxylating p-cresol with hydrogen peroxide using titanium-silicon molecular sieve as a catalyst. The selectivity of ...
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