CN110642671B - System and method for continuously preparing Grignard reagent to synthesize phenethyl alcohol - Google Patents

Abstract

The present invention relates to a system and method for continuously preparing Grignard reagent for synthesizing phenethyl alcohol. The system comprises a tower reactor for continuously preparing Grignard reagent by reacting chlorobenzene compound solution with magnesium, and the tower reactor is along the height direction. It is divided into a plurality of reaction areas by dividing plates, and each divided area is provided with multi-layer stirring paddles. The system also includes a lattice reaction kettle, a falling film scraper evaporator, an enamel reaction kettle, a continuous layerer, an extractor and Rectification tower; magnesium and chlorobenzene flow countercurrently in the tower reactor, and the reaction is completed during the flow process, and the unreacted magnesium mud is removed by sedimentation separation to obtain the Grignard reagent reaction solution, the Grignard reagent reaction solution and the ethylene oxide solution The mixed reaction yields substituted phenethyl alcohol. Compared with the prior art, the present invention has stable feeding speed of raw materials and stable heat generated by the reaction, can avoid the risk of instant exothermic large reaction out of control, greatly improves safety, avoids back mixing, greatly improves selectivity, and is suitable for industrial production.

Description

A system and method for continuously preparing Grignard reagent to synthesize phenethyl alcohol

technical field

The invention belongs to the field of flavors and fragrances, and relates to a method for continuously preparing Grignard reagent to synthesize phenethyl alcohol.

Background technique

Phenethyl alcohol, also known as 2-phenylethyl alcohol, has the molecular formula: C ₈ H ₁₀ O, and its molecular structural formula (I) is shown:

Phenylethyl alcohol is one of the most important spice varieties in the aromatic family. It has an elegant and delicate rose fragrance. Its aroma is soft and sweet. It is mainly used for rose, caramel, honey and other fruity food flavors and various wines. The preparation of flavors and tobacco flavors is also an indispensable substance in rose and other plant flavors, and its stability to alkali makes it specially used in soaps and other flavors.

At present, there are many literatures for synthesizing phenethyl alcohol (CN1465557A, US2125490A and US2483323A). The benzene-oxirane method utilizes the "Friedel-Crafts" reaction to synthesize phenethyl alcohol. This method has low investment and low equipment requirements, but has many side reactions and poor selectivity. , and produce a large amount of acidic wastewater containing benzene, and the yield is generally 40-65%; and the benzene-oxirane method utilizes Grignard reagent to synthesize phenethyl alcohol, although the yield is high, but the intermittent reaction production efficiency is low, safety not tall.

The reaction equation is as follows:

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a system and method for continuously preparing Grignard reagent for synthesizing phenethyl alcohol in order to overcome the defects existing in the above-mentioned prior art.

The object of the present invention can be realized through the following technical solutions:

The invention provides a system for continuously preparing Grignard reagent for synthesizing phenethyl alcohol, comprising a tower reactor for continuously preparing Grignard reagent by reacting chlorobenzene compound solution with magnesium, the tower reactor passing through a dividing plate along the height direction It is divided into a plurality of reaction zones, and each separation zone is provided with a multi-layer stirring paddle.

The separators in the present invention serve to separate the reaction liquids on both sides of the separators, so as to reduce the effect of back-mixing of materials between the separators; the stirring paddles are used to achieve a complete mixing effect of the reaction liquids in each separation area.

As a preferred technical solution of the present invention, the chlorobenzene compound solution enters the tower reactor from the bottom of the tower, magnesium (preferably using magnesium powder) enters the tower reactor from the top of the tower, and the chlorobenzene compound solution and magnesium are countercurrent in the tower reactor. Contact, the Grignard reaction liquid flows out from the top of the tower.

As a preferred technical solution of the present invention, each reaction zone of the tower reactor is provided with a cooling coil, and each reaction zone of the tower reactor is provided with a cooling jacket.

As a preferred technical solution of the present invention, a reflux cooler is provided at the top of the tower reactor.

As a preferred technical solution of the present invention, the system also includes a lattice reactor, a falling-film scraper evaporator, an enamel reactor, a continuous stratifier, an extractor and a rectifying column;

Described lattice reaction kettle is used for the continuous inflow of the lattice reaction liquid flowing out of ethylene oxide solution and tower reactor, and the reaction under cooling condition,

The described falling film scraper evaporator is used for the continuous concentration of the reaction solution flowing out of the lattice reactor and the continuous recovery of the solvent,

Described enamel reaction kettle is used for the continuous inflow of hydrochloric acid solution and concentrated lattice reaction kettle reaction solution, and the neutralization under cooling and stirring conditions,

The continuous layering device is used for the continuous inflow of the effluent of the enamel reaction kettle, and the layering of the organic phase and the water phase in the effluent of the enamel reaction kettle,

The extractor is used for the continuous inflow of the water phase, and the continuous extraction of the reaction product in the water phase is carried out by the continuous inflow of toluene,

The rectifying column is used for the continuous inflow of the organic phase and the extract, and the reaction product is obtained through rectification.

The present invention also provides a method for continuously preparing Grignard reagent for synthesizing phenethyl alcohol. Using the system, the method includes the steps of continuously preparing Grignard reagent with chlorobenzene compound solution and magnesium in a tower reactor.

As a preferred technical solution of the present invention, the method further comprises the continuous reaction of Grignard reagent and ethylene oxide solution to prepare phenethyl magnesium salt, and the phenethyl magnesium salt is neutralized, layered and rectified to obtain phenethyl alcohol.

As the preferred technical solution of the present invention;

Before the continuous preparation of Grignard reagent, first prepare a grignard reagent solution with a volume of 60-90% of the tower reactor as bottom material, and keep enough magnesium for 1-5h reaction in the tower reactor (to maintain the excess of magnesium in the continuous reaction process). );

The continuous preparation of Grignard reagents is carried out under reflux conditions.

As a preferred technical solution of the present invention, the chlorobenzene compound solution adopts the tetrahydrofuran solution of the chlorobenzene compound with a concentration of 10-30wt%, and the chlorobenzene compound solution and magnesium quantitatively enter the tower reactor continuously, and the benzene compound solution and The proportion of magnesium is such that the excess of magnesium is between 0 and 1% (in molar ratio, adjusted according to the actual excess of magnesium in the reaction).

As the preferred technical scheme of the present invention:

The ethylene oxide solution adopts the tetrahydrofuran solution of ethylene oxide. During the continuous reaction of Grignard reagent and ethylene oxide solution, the molar ratio of ethylene oxide and chlorobenzene compound is controlled to be between 1:1±0.05 (during operation). The actual operation ratio is adjusted according to the detection result), and the tetrahydrofuran is directly recovered after the format reaction finishes;

After the tetrahydrofuran is recovered, 10% hydrochloric acid is continuously used for neutralization, and the neutralization to pH 3-6 is the end point.

Compared with the prior art, the present invention has the following beneficial effects:

(1) reaction raw material magnesium (preferably magnesium powder) is added from the top of the tower reactor, the chlorobenzene compound solution (preferably the tetrahydrofuran solution of the chlorobenzene compound) is added from the bottom of the tower, two kinds of raw materials flow countercurrently in the tower reactor, and the chlorine The benzene compound rises from the bottom to the top and the reaction ends. The reaction time is short and the selectivity is high.

(2) Install a large number of cooling coils in the tower reactor, add a jacket on the outer surface for cooling, and add a total reflux cooler at the top of the reaction tower, preferably a reflux cooler with a cooling area more than 20 times the volume of the reactor to ensure Instantly transfers the heat generated by the reaction.

(3) The reaction process is carried out continuously, the feeding speed of raw materials is stable, and the heat generated by the reaction is stable, which can avoid the risk of the reaction running out of control due to the instantaneous exothermic heat.

(4) The partition plate acts as a relative distance between the materials in different areas; and the stirring paddle acts as a mixing function, so that the materials in the area can be fully mixed. The interaction between the separation plate and the stirring paddle can make the reactor achieve the effect of multi-stage kettle type series connection, and the number of stages can be designed as needed, which theoretically eliminates the influence of back-mixing factors.

(5) The present invention realizes the continuous synthesis of phenethyl alcohol.

Description of drawings

Fig. 1 is the schematic diagram of the system of the present invention for continuously preparing Grignard reagent to synthesize phenethyl alcohol.

In the figure, 1 is a tower reactor, 11 is a dividing plate, 12 is a reaction zone, 13 is a stirring paddle, 14 is a cooling coil, 15 is a cooling jacket, 16 is a reflux cooler, and 2 is a format reactor, 3 is a falling film scraper evaporator, 4 is an enamel reaction kettle, 5 is a continuous stratifier, 6 is an extractor, and 7 is a rectifying tower.

Detailed ways

A method for continuously preparing a Grignard reagent for synthesizing phenethyl alcohol, the process comprising the steps of continuously preparing a Grignard reagent from a solution of a chlorobenzene compound and magnesium; the prepared Grignard reagent is continuously reacted with an ethylene oxide solution to prepare a magnesium phenethylate, magnesium The salt is neutralized, layered, rectified and other steps to obtain phenethyl alcohol.

The above-mentioned method is reacted in the system (referring to Fig. 1) that continuously prepares Grignard reagent to synthesize phenethyl alcohol: the continuous preparation of Grignard reagent is carried out in tower reactor 1, and the preparation of magnesium phenethylate is carried out in lattice reactor 2. After the reaction is finished, the solvent is directly recovered with the falling-film scraper evaporator 3, the neutralization of the magnesium salt is carried out in the enamel reaction kettle 4, the layering is carried out in the continuous layerer 5, and the water phase after the layering is in the extractor 6. Extraction is carried out in the rectification column 7, and rectification is carried out.

Preferably, the tower reactor is divided into a plurality of reaction areas 12 by dividing plates 11 (mesh plates can be used) along the height direction, and each dividing area 12 is provided with a multi-layer stirring paddle 13 . A cooling coil 14 is provided inside each reaction zone 12 of the tower reactor 1 , and a cooling jacket 15 is provided outside each reaction zone 12 of the tower reactor 1 . A reflux cooler 16 is provided at the top of the tower reactor 1 . The chlorobenzene compound solution enters the tower reactor 1 from the bottom of the tower, and the magnesium enters the tower reactor 1 from the top of the tower. Before continuously preparing Grignard reagent, firstly (by batch method) prepare 60~90% grignard reagent solution by volume of tower reactor 1 as bottom material, and keep enough magnesium for 1~5h reaction in tower reactor 1, so as to The magnesium excess is maintained during the continuous reaction process. The chlorobenzene compound solution adopts the tetrahydrofuran solution of the chlorobenzene compound with a concentration of 10-30wt%, the chlorobenzene compound solution and magnesium quantitatively and continuously enter the tower reactor 1, and the ratio of the benzene compound solution and the magnesium is controlled to make the magnesium excess 0-1%. room (in molar ratio). The continuous preparation of Grignard reagents is carried out under reflux conditions.

Preferably, the lattice reactor 2 is used for the continuous inflow of the ethylene oxide solution and the lattice reaction liquid flowing out of the tower reactor 1, and the reaction under cooling conditions; the falling-film scraped-plane evaporator 3 is used for the outflow of the lattice reactor 2 The continuous concentration of the reaction solution and the continuous recovery of the solvent; the enamel reaction kettle 4 is used for the continuous inflow of the hydrochloric acid solution and the concentrated lattice reaction kettle reaction solution, and the neutralization under cooling and stirring conditions; the continuous stratifier 5 is used for the enamel The continuous inflow of the reaction kettle effluent, and the stratification of the organic phase and the water phase in the enamel reaction kettle effluent; the extractor 6 is used for the continuous inflow of the water phase, and by the continuous inflow of toluene to carry out the continuous extraction of the reaction product in the water phase; The rectification column 7 is used for the continuous inflow of the organic phase and the extraction liquid, and the reaction product is obtained by rectification. The ethylene oxide solution adopts the tetrahydrofuran solution of ethylene oxide. During the continuous reaction of Grignard reagent and ethylene oxide solution, the molar ratio of ethylene oxide and chlorobenzene compound is controlled to be between 1:1±0.05. After the end, the tetrahydrofuran is directly recovered; after the recovery of the tetrahydrofuran, 10% hydrochloric acid is continuously used for neutralization, and the neutralization is performed to a pH value of 3-6 as the end point.

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1

The tower reactor 1 is 600mm in diameter, 8 meters high in the reaction section, 1 meter high in the sedimentation separation section, 900mm in diameter; the volume of the reaction section is 2.2 cubic meters, and the sedimentation section is 0.63 cubic meters. The top of the settling section is provided with an area of 10 square tubular total reflux condenser and magnesium powder continuous feeder. Every 2 meters of the reaction section is a section (one reaction area), the sections are connected by flanges, and a partition plate is installed, each section is equipped with an outer jacket, and a cooling coil is installed inside; the stirring distance is 500mm, three-blade paddle, paddle The length of the blade is 200mm, and there are three layers of stirring paddles between the separation plates.

In the tower, add the reacted Grignard reagent of 90% of the tower volume in advance, continuously inject 280 kg/hour (0.5Kmol/hour) of chlorobenzene tetrahydrofuran solution (mass ratio concentration is 20%) from the bottom of the Grignard reaction tower, 12.3 kg/h (0.506 Kmol/h) of magnesium powder was continuously added from the top of the tower. The stirring speed was controlled to be 60 rev/min, and the reaction was continued under the condition of cooling with a jacket and a cooling coil and slight reflux. The Grignard reaction solution flowing out from the top of the tower was sampled with ice-added dilute hydrochloric acid, and the content of the GC analysis was 99.5%. The Grignard reaction solution overflowed from the tower reactor flows into a 500-liter Grignard reactor, and simultaneously 148 kg/hour (0.505 kg/h) of a mixed solution of ethylene oxide tetrahydrofuran (15% by mass) is input with a pump. Kmol/hour) to carry out the reaction under cooling conditions.

After the reaction, the reaction solution flows through the falling film wiper evaporator to continuously recover tetrahydrofuran. The concentrated reaction solution was flowed into a 500-liter enamel reaction kettle with an overflow outlet, cooled and continuously neutralized with 10% hydrochloric acid solution under stirring conditions to a pH value of 3-5. The reaction liquid overflowing from the enamel kettle enters a continuous stratifier, and the upper organic phase is collected. The aqueous phase was continuously extracted with 50 liters/hour of toluene, and the organic phases were combined to recover the solvent and then rectified to obtain pure phenethyl alcohol. The purity of the product reaches more than 99.9%, and the quality meets the quality requirements of food-grade additives. According to time, 57.5 kg/h of product can be obtained per hour, and the yield reaches 94.2%.

Example 2

From the bottom of the 600mm tower reactor, 560 kg/hour (0.5Kmol/hour) of chlorobenzene tetrahydrofuran solution (mass ratio concentration of 10%) was continuously injected, and 12.0 kg/hour (0.5Kmol/hour) of magnesium powder was continuously added from the top of the tower. . The stirring speed was controlled to be 60 rev/min, and the reaction was continued under the condition of cooling with a jacket and a cooling coil and slight reflux. The Grignard reaction solution overflowed from the Grignard reaction tower flows into a 500-liter Grignard reaction kettle (GC analysis content is 98.9%), and a mixed solution 146 of ethylene oxide tetrahydrofuran (mass ratio concentration of 15%) is input with a pump at the same time. The reaction was carried out in kg/h (0.501 Kmol/h) under cooling.

After the reaction, the reaction solution flows through the falling film wiper evaporator to continuously recover tetrahydrofuran. The concentrated reaction solution was poured into a 500-liter enamel reaction kettle with an overflow port, cooled and continuously neutralized with 10% hydrochloric acid solution under stirring conditions to a pH value of 4-6. The reaction liquid overflowing from the enamel reactor enters a continuous stratifier, and the upper organic phase is collected. The aqueous phase was continuously extracted with 50 liters/hour of toluene, and the organic phases were combined to recover the solvent and then rectified to obtain pure phenethyl alcohol. The purity of the product reaches more than 99.9%, and the quality meets the quality requirements of food-grade additives. According to time, 55.5 kg/h of product can be obtained per hour, and the yield reaches 91.0%.

Example 3

From the bottom of the 600mm tower reactor, 1 kg/hour (0.5Kmol/hour) of chlorobenzene tetrahydrofuran solution (mass ratio concentration of 30%) was continuously injected, and 12.2 kg/hour (0.502Kmol/hour) of magnesium powder was continuously added from the top of the tower. . The stirring speed was controlled to be 60 rev/min, and the reaction was continued under the condition of cooling with a jacket and a cooling coil and slight reflux. The Grignard reaction solution overflowed from the Grignard reaction tower flows into a 500-liter Grignard reaction kettle, and simultaneously 154 kg/hour (0.525 kg/h) of a mixed solution of ethylene oxide tetrahydrofuran (mass ratio concentration of 15%) is input with a pump. Kmol/hour) to carry out the reaction under cooling conditions.

After the reaction, the reaction solution flows through the falling film wiper evaporator to continuously recover tetrahydrofuran. The concentrated reaction solution was flowed into a 500-liter enamel reaction kettle with an overflow port, cooled and continuously neutralized with 10% hydrochloric acid solution under stirring conditions to a pH value of 4-6. The reaction liquid overflowing from the enamel reactor enters a continuous stratifier, and the upper organic phase is collected. The aqueous phase was continuously extracted with 50 liters/hour of toluene, and the organic phases were combined to recover the solvent and then rectified to obtain pure phenethyl alcohol. The purity of the product reaches more than 99.9%, and the quality meets the quality requirements of food-grade additives. According to time, 56.7 kg/h of product can be obtained per hour, and the yield reaches 93.1%.

The foregoing description of the embodiments is provided to facilitate understanding and use of the invention by those of ordinary skill in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made, and the generic principles described herein can be applied to other embodiments without inventive step. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should all fall within the protection scope of the present invention.

Claims (6)

1. A system for continuously preparing and synthesizing phenethyl alcohol is characterized by comprising a tower reactor for continuously preparing Grignard reagent by reacting chlorobenzene compound solution with magnesium, wherein the tower reactor is divided into a plurality of reaction areas along the height direction by partition plates, and each divided area is internally provided with a plurality of layers of stirring paddles;

the chlorobenzene compound solution enters a tower reactor from the bottom of the tower, the magnesium enters the tower reactor from the top of the tower, the chlorobenzene compound solution and the magnesium are in countercurrent contact in the tower reactor, and the Grignard reaction solution flows out from the top of the tower;

a cooling coil is arranged in each reaction area of the tower reactor, and a cooling jacket is arranged outside each reaction area of the tower reactor;

a reflux cooler is arranged at the top of the tower reactor;

the system also comprises a lattice reaction kettle, a falling film scraper evaporator, an enamel reaction kettle, a continuous delayer, an extractor and a rectifying tower;

the lattice reaction kettle is used for the continuous inflow of an ethylene oxide solution and a lattice reaction liquid flowing out of the tower reactor and the reaction under the cooling condition,

the falling film scraper evaporator is used for continuously concentrating reaction liquid flowing out of the grignard reaction kettle and continuously recovering a solvent,

the enamel reaction kettle is used for continuous inflow of a hydrochloric acid solution and a concentrated reaction solution of the lattice reaction kettle, and neutralization under the conditions of cooling and stirring,

the continuous delayer is used for continuously flowing the effluent liquid of the enamel reaction kettle and delaminating the organic phase and the water phase in the effluent liquid of the enamel reaction kettle,

the extractor is used for the continuous inflow of the water phase and the continuous extraction of the reaction product in the water phase through the continuous inflow of toluene,

the rectifying tower is used for continuously flowing in an organic phase and an extraction liquid and obtaining a reaction product through rectification.

2. A method for continuously preparing a grignard reagent-synthesized phenethyl alcohol, which comprises the step of continuously preparing the grignard reagent in a column reactor with a chlorobenzene compound solution and magnesium by using the system of claim 1.

3. The method for continuously preparing the Grignard reagent for synthesizing the phenethyl alcohol according to claim 2, further comprising continuously reacting the Grignard reagent with an ethylene oxide solution to prepare the magnesium phenethyl alcohol salt, wherein the magnesium phenethyl alcohol salt is neutralized, layered and rectified to obtain the phenethyl alcohol.

4. The method for continuously preparing the Grignard reagent for synthesizing the phenethyl alcohol according to claim 3, wherein;

before continuously preparing the lattice reagent, preparing a lattice reagent solution with the volume of 60-90% of that of the tower reactor as a bottom material, and keeping enough magnesium for reaction for 1-5 hours in the tower reactor;

the continuous preparation of the grignard reagent was carried out under reflux conditions.

5. The method for continuously preparing the Grignard reagent synthesized phenethyl alcohol according to claim 3, wherein the chlorobenzene compound solution is 10-30 wt% of a tetrahydrofuran solution of a chlorobenzene compound, the chlorobenzene compound solution and magnesium are quantitatively and continuously fed into the tower reactor, and the ratio of the benzene compound solution to the magnesium is controlled so that the magnesium is excessive by 0-1%.

6. The method for continuously preparing the Grignard reagent for synthesizing the phenethyl alcohol according to claim 5, wherein:

the ethylene oxide solution is tetrahydrofuran solution of ethylene oxide, the molar ratio of the ethylene oxide to the chlorobenzene compound is controlled to be 1:1 +/-0.05 in the continuous reaction process of the Grignard reagent and the ethylene oxide solution, and the tetrahydrofuran is directly recovered after the Grignard reaction is finished;

after the tetrahydrofuran is recovered, continuously neutralizing with 10% hydrochloric acid until the pH value is 3-6.

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