CN101353295B

CN101353295B - Preparation of p-hydroxybenzene methyl ether

Info

Publication number: CN101353295B
Application number: CN2008101247152A
Authority: CN
Inventors: 郎玉成
Original assignee: JIANGSU LIANHUA TECHNOLOGY Co Ltd
Current assignee: JIANGSU LIANHUA TECHNOLOGY Co Ltd
Priority date: 2008-09-01
Filing date: 2008-09-01
Publication date: 2011-07-20
Anticipated expiration: 2028-09-01
Also published as: CN101353295A

Abstract

A preparation method of p-methoxyphenol comprises the steps as follows: hydroquinone, methane chloride, inorganic alkali, a solvent and water are added into a pressure kettle, stirred, separated, distilled and rectified in vacuum to obtain the p-methoxyphenol under the alkaline condition, wherein, the weight ratio of the hydroquinone to the methane chloride is 1:0.46-0.8, the weight ratio of the hydroquinone to the inorganic alkali is 1:0.36-0.65, and the weight ratio of the hydroquinone to the solvent is 1:2-5. The method has the advantages that hypertoxic dimethyl sulfate is replaced by themethane chloride so that the toxicity of the raw materials for production is reduced; the belt-press reaction is carried out to improve the reaction selectivity, therefore, a high-purity product withthe purity being more than 99.5% is obtained; the product yield is over 95%, which is greatly improved compared with the existing method; the finished product with stable quality can be obtained by the processes of distillation and vacuum rectification of the reaction solution, therefore, the preparation method simplifies the processing step of the reaction solution, and greatly reduces the production cost.

Description

The preparation method of MEHQ

Technical field

The present invention relates to a kind of preparation method of MEHQ, belong to the field of chemical synthesis.

Background technology

MEHQ has another name called the hydroquinone monomethyl ether, p methoxy phenol, molecular formula C ₇H ₈O ₂, molecular weight 124.14, structural formula is: To the hydroxyl methyl ether is white crystalline solid, and zero pour 55-57 ℃, 243 ℃ of boiling points are insoluble to cold water.MEHQ is an important chemical material of synthetic aryl nitrone liquid crystal, also can be used as dyestuff intermediate.And can be used as high-efficiency polymerization inhibitor in the olefin monomers such as producing vinyl cyanide, vinylformic acid, methacrylic acid and ester class thereof, can also be as the stablizer of unsaturated polyester and ultraviolet inhibitor etc., purposes is very extensive, and according to different raw materials, this compound has multiple synthetic method.Understand according to the applicant, application number is 00126631.4, the applying date is 2000.10.12, the Chinese invention patent application that name is called " method for preparing MEHQ with Para-Anisidine " discloses a kind of method for preparing MEHQ with Para-Anisidine through diazotization, hydrolysis reaction, its shortcoming is: the hydrolysis of diazonium salt must be carried out under high acid solution and higher temperature, cause diazonium salt to decompose easily, and the waste water that uses this method to produce is more, yield is lower, is not suitable for industrial applications.At present, domestic and international synthesizing about MEHQ, mainly be to be raw material with the Resorcinol, adopt the synthetic MEHQ of methyl-sulfate method or methyl alcohol catalysis method, wherein, the shortcoming of methyl-sulfate method is: itself belongs to highly toxic product methyl-sulfate, price is expensive, react strict, because its chemical property is more active, poor selectivity in reaction, except that terephthaldehyde's ether of generation about 30%, also very easily produce other tarry by product, intractability is big in feasible the production, and has influenced the quality and the yield of product; The methyl alcohol catalysis method has been avoided the toxicity of methyl-sulfate, and the highest yield can reach about 82%, but its shortcoming is: the benzene that toxicity commonly used is bigger is made solvent, or the crown ether that toxicity commonly used is big and price is high is as catalyzer, and the subsequent processes of complexity such as reaction solution needs through extraction, neutralization, washing, concentrates, underpressure distillation, recrystallization just can obtain stay-in-grade product.

Summary of the invention

The objective of the invention is the shortcoming that exists at prior art, propose that a kind of product purity height, yield height, cost are low, the preparation method of the MEHQ that is suitable for suitability for industrialized production.

The objective of the invention is to be achieved through the following technical solutions: the preparation method of MEHQ, be under alkaline condition, Resorcinol, monochloro methane, mineral alkali, solvent and water are placed autoclave pressure, step through stirring, separation, distillation and rectification under vacuum makes MEHQ, wherein, the weight ratio that feeds intake of Resorcinol and monochloro methane is 1:0.46～0.8, the weight ratio that feeds intake of Resorcinol and mineral alkali is 1:0.36～0.65, the weight ratio that feeds intake of Resorcinol and solvent is 1:2～5, and the weight ratio that feeds intake of mineral alkali and water is 1:1～5; Mineral alkali is one or more in sodium hydroxide, potassium hydroxide, sodium bicarbonate, the saleratus; Solvent is one or more in toluene, the dimethylbenzene.

In the whipping step, temperature of reaction is 60 ℃～100 ℃, and pressure-controlling is below 1MPa, and the reaction times is 4～8 hours.

In the rectification under vacuum step, below vacuum tightness 0.009MPa, collect 165 ℃～170 ℃ cuts, be MEHQ.

Preparation method's of the present invention reaction process following (mineral alkali is example with sodium hydroxide):

The invention has the beneficial effects as follows: the methyl-sulfate that substitutes severe toxicity with monochloro methane, reduced the toxicity of raw materials for production, and adopt band to press reaction, thereby make the selectivity raising of reaction obtain purity at the high purity product more than 99.5%, yield is more than 95%, is greatly improved with respect to existing method yield; Reaction solution only need carry out rectification under vacuum through behind the distillating recovering solvent, in specified for temperature ranges, just can obtain the high finished product of steady quality purity, simplify the treatment step of reaction solution, realize cleaning production, production cost reduces greatly, is suitable for suitability for industrialized production.

Embodiment

Below in conjunction with embodiment technical scheme of the present invention is described in detail.

Embodiment one

With the 110g Resorcinol, the 66g monochloro methane, 40g sodium hydroxide, 320g toluene and 100g water place the autoclave pressure of 1000ml, close still, open and stir and heating system, material in the autoclave pressure is carried out temperature reaction, this moment, the pressure of reactor was made as 0.7MPa, and controlled temperature relaxed in 2 hours and rises to 90 ℃, insulation reaction was taken a sample after 6 hours, detect the Resorcinol surplus through gas-chromatography (GC) and be reaction end less than 0.2%, termination reaction and cooling, question response liquid standing demix moves to the organic phase of telling in the still kettle, and toluene is reclaimed in first air distillation, still temperature to be distilled reaches 150 ℃ of air distillations and finishes, carry out rectification under vacuum, vacuum tightness is 0.009MPa, and temperature is front-end volatiles at 165 ℃, the cut of collecting 165 ℃～170 ℃ is MEHQ, weigh product 118.6g, be 95.6% with the Resorcinol rate of collecting, be 99.6% through the GC purity assay.

Embodiment two

With the 110g Resorcinol, the 56g monochloro methane, the 40g sodium bicarbonate, 320g toluene and 100g water place the autoclave pressure of 1000ml, close still, open and stir and heating system, material in the autoclave pressure is carried out temperature reaction, this moment, the pressure of reactor was made as 0.8MPa, and controlled temperature relaxed in 2 hours and rises to 90 ℃, insulation reaction was taken a sample after 8 hours, detect the Resorcinol surplus through GC and be reaction end less than 0.2%, termination reaction and cooling, question response liquid standing demix moves to the organic phase of telling in the still kettle, and toluene is reclaimed in first air distillation, still temperature to be distilled reaches 150 ℃ of air distillations and finishes, carrying out rectification under vacuum, is under the 0.009MPa in vacuum tightness, and temperature is front-end volatiles at 165 ℃, the cut of collecting 165 ℃～170 ℃ is MEHQ, weigh product 118g, be 95.2% with the Resorcinol rate of collecting, be 99.5% through the GC purity assay.

Embodiment three

With the 110g Resorcinol, the 76g monochloro methane, the mixture of 40g sodium hydroxide and sodium bicarbonate, 320g dimethylbenzene and 100g water place the autoclave pressure of 1000ml, close still, open and stir and heating system, material in the autoclave pressure is carried out temperature reaction, this moment, the pressure of reactor was made as 0.9MPa, and controlled temperature relaxed in 2 hours and rises to 90 ℃, insulation reaction was taken a sample after 5 hours, detect the Resorcinol surplus through GC and be reaction end less than 0.2%, termination reaction and cooling, question response liquid standing demix moves to the organic phase of telling in the still kettle, and toluene is reclaimed in first air distillation, still temperature to be distilled reaches 150 ℃ of air distillations and finishes, carry out rectification under vacuum, vacuum tightness is 0.009MPa, and temperature is front-end volatiles at 165 ℃, the cut of collecting 165 ℃～170 ℃ is MEHQ, weigh product 119g, be 96.0% with the Resorcinol rate of collecting, be 99.5% through the GC purity assay.

Embodiment four

With the 150kg Resorcinol, the 90kg monochloro methane, 60kg sodium hydroxide, the mixture of sodium bicarbonate and saleratus, 320kg toluene and 100kg water place the autoclave pressure of 1000L, close still, open and stir and heating system, material in the autoclave pressure is carried out temperature reaction, this moment, the pressure of reactor was made as 0.7MPa, and controlled temperature relaxed in 2 hours and rises to 90 ℃, insulation reaction was taken a sample after 5 hours, detect the Resorcinol surplus through GC and be reaction end less than 0.2%, termination reaction and cooling, question response liquid standing demix moves to the organic phase of telling in the still kettle, toluene is reclaimed in elder generation's air distillation, still temperature to be distilled reaches 150 ℃ of air distillations and finishes, and carries out rectification under vacuum, and vacuum tightness is 0.009MPa, temperature is front-end volatiles at 165 ℃, the cut of collecting 165 ℃～170 ℃ is MEHQ, and product gets finished product through slice packaging, and 161kg weighs, with the Resorcinol rate of collecting is 95.8%, is 99.6% through the GC purity assay.

Embodiment five

With the 200kg Resorcinol, the 100kg monochloro methane, 80kg saleratus and potassium hydroxide mixture, 400kg dimethylbenzene and 150kg water place the autoclave pressure of 1000L, close still, open and stir and heating system, material in the autoclave pressure is carried out temperature reaction, this moment, the pressure of reactor was made as 0.8MPa, and controlled temperature relaxed in 2 hours and rises to 90 ℃, insulation reaction was taken a sample after 6 hours, detect the Resorcinol surplus through GC and be reaction end less than 0.2%, termination reaction and cooling, question response liquid standing demix moves to the organic phase of telling in the still kettle, toluene is reclaimed in elder generation's air distillation, still temperature to be distilled reaches 150 ℃ of air distillations and finishes, and carries out rectification under vacuum, and vacuum tightness is 0.009MPa, temperature is front-end volatiles at 165 ℃, the cut of collecting 165 ℃～170 ℃ is MEHQ, and product gets finished product through slice packaging, and 215kg weighs, with the Resorcinol rate of collecting is 95.2%, is 99.5% through the GC purity assay.

Embodiment six

With the 180kg Resorcinol, the 90kg monochloro methane, 75kg saleratus and potassium hydroxide mixture, 380kg toluene and 150kg water place the autoclave pressure of 1000L, close still, open and stir and heating system, material in the autoclave pressure is carried out temperature reaction, this moment, the pressure of reactor was made as 0.8MPa, and controlled temperature relaxed in 2 hours and rises to 90 ℃, insulation reaction was taken a sample after 5 hours, detect the Resorcinol surplus through GC and be reaction end less than 0.2%, termination reaction and cooling, question response liquid standing demix moves to the organic phase of telling in the still kettle, toluene is reclaimed in elder generation's air distillation, still temperature to be distilled reaches 150 ℃ of air distillations and finishes, and carries out rectification under vacuum, and vacuum tightness is 0.009MPa, temperature is front-end volatiles at 165 ℃, the cut of collecting 165 ℃～170 ℃ is MEHQ, and product gets finished product through slice packaging, and 194.2kg weighs, with the Resorcinol rate of collecting is 95.6%, is 99.5% through the GC purity assay.

In addition to the implementation, the present invention can also have other embodiments, and all employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of the utility model requirement.

Claims

1. the preparation method of MEHQ, it is characterized in that: under alkaline condition, Resorcinol, monochloro methane, mineral alkali, solvent and water are placed autoclave pressure, step through stirring, separation, distillation and rectification under vacuum makes MEHQ, wherein, the weight ratio that feeds intake of Resorcinol and monochloro methane is 1: 0.46～0.8, the weight ratio that feeds intake of Resorcinol and mineral alkali is 1: 0.36～0.65, the weight ratio that feeds intake of Resorcinol and solvent is 1: 2～5, and the weight ratio that feeds intake of mineral alkali and water is 1: 1～5; Described mineral alkali is one or more in sodium hydroxide, potassium hydroxide, sodium bicarbonate, the saleratus; Described solvent is one or more in toluene, the dimethylbenzene; Temperature of reaction is 60～100 ℃ in the described whipping step, and pressure-controlling is below 1MPa, and the reaction times is 4～8 hours.

2. according to the preparation method of the described MEHQ of claim 1, it is characterized in that: in the described rectification under vacuum step, below vacuum tightness 0.009MPa, collect 165～170 ℃ of cuts, be MEHQ.