CN101838196B

CN101838196B - Method for preparing propylene glycol monomethyl ether acetate (PMA) by continuous reaction and distillation

Info

Publication number: CN101838196B
Application number: CN2010101488353A
Authority: CN
Inventors: 汪尚飞; 朱宏文; 叶四华; 罗国恩; 冯佩洪; 罗雨
Original assignee: JIANGMEN HANDSOME CHEMICAL DEVELOPMENT Co Ltd
Current assignee: Taixing Jinjiang Chemical Industry Co.,Ltd.
Priority date: 2010-04-14
Filing date: 2010-04-14
Publication date: 2012-05-30
Anticipated expiration: 2030-04-14
Also published as: CN101838196A

Abstract

The invention discloses a method for preparing propylene glycol monomethyl ether acetate (PMA) by continuous reaction and distillation. The method comprises the following steps of: mixing propylene glycol methyl ether and acetic acid serving as raw materials in a mol ratio of 1 to 1, and preheating the mixture; allowing the mixture to enter a fixed bed reactor for pre-reaction and then enter an esterification reactor for temperature raising and further reaction; performing rectification, condensing and phase-splitting on the gasified reaction crude product to obtain an oil phase and a water phase; refluxing a part of the upper-layer oil phase to an esterification tower top and the rest to a crude ester jar for preliminary treatment and then light components removal treatment; refluxing a part of the collected lower-layer water phase to the esterification tower top and allowing the balance to the recovery section for treatment, wherein the catalyst for the fixed bed reaction is sulfonyl strongly acidic ion-exchange resin; and the catalyst for the esterification reactor is one of sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid and mixed catalyst A. The method realizes the continuous and pollution-free production of the PMA.

Description

A kind of successive reaction rectifying prepares the working method of PMA

Technical field

The present invention relates to the working method that a kind of successive reaction rectifying prepares 1-Methoxy-2-propyl acetate (PMA), specifically is to be raw material with propylene glycol monomethyl ether and acetic acid, and successive reaction rectifying makes 1-Methoxy-2-propyl acetate (PMA) under an acidic catalyst.

Background technology

1-Methoxy-2-propyl acetate (PMA) is a kind of low toxicity advanced industrial solvent of excellent property.Because group-ehter bond and hydroxyl that PMA has 2 strong dissolving functions; The former has oleophilicity, solubilized hydrophobic nature compound, latter's possess hydrophilic property; Polarity and nonpolar material all there is very strong dissolving power; In addition, PMA also has characteristics such as Heat stability is good, little, the high foaming of viscosity variation and corrodibility are little, thereby is widely used in industries such as coating, printing ink, clean-out system, printing, textile dyestuff and leather retanning agent.The demand of propylene glycol methyl ether acetate increases day by day in recent years, is progressively substituting to be widely used at present but the higher glycol ether carboxylicesters of toxicity.

At present, domestic PMA producer mostly adopts rhythmic reaction dehydration production technique, and the catalyzer that is adopted during reaction is synthetic is the vitriol oil normally.Mainly there is following problem in this traditional technology:

1) long reaction time, byproduct of reaction is more, and yield is not high;

2) the equipment corrosion problem is still apparent in view, causes the ME cost higher;

3) reaction often needs to adopt the band aqua, and common the having at present of band aqua: benzene,toluene,xylene, hexanaphthene etc., but still carry the reactant of 5-10% easily secretly, and the band aqua aborning can be very harmful to people's health, contaminate environment easily;

4) reaction product needs neutralization, complex operation, and cause problem such as the higher and catalyst loss of acetic acid unit consumption;

5) sediment such as catalyzer and acetate causes pipeline and filler to stop up easily, the influence operation, and overhaul of the equipments also bothers.

In a word, problem such as the yield that traditional intermittence, the esterification technique method highlighted is on the low side, corrosion is laid particular stress on, the material consumption energy consumption is higher has restricted the popularization production of PMA greatly, has also influenced the market efficiency of PMA.

Summary of the invention

Problems such as the present invention aims to provide the working method that a kind of successive reaction rectifying prepares PMA, and the yield that this method can avoid traditional batch technology to bring is low, corrosion is higher realize clean environment firendly production.

The inventive method is following:

The raw material propylene glycol monomethyl ether gets into one section fixed-bed reactor with after acetic acid mixed preheating in 1: 1 in molar ratio, gets into the esterifying kettle further reaction that heats up after the pre-reaction.The reacting coarse product gasification is after after rectifying, condensation and the phase-splitting, a upper oil phase part is back to the esterification cat head, and remaining part removes thick ester jar after go to take off light processing after the rough handling, and lower floor's water part is back to the esterification cat head, and all the other go recycle section to handle.

In said fixed bed, the recycle ratio R that material adopts is 3-10.

In said fixed bed, the catalyzer of using belongs to strong-acid ion exchange resin, and the catalyzer that is adopted in the esterifying kettle is a kind of among sulfuric acid, methylsulfonic acid, tosic acid and the mixed catalyst A, and catalytic amount accounts for the 0.5-3w% of total material.

In present method, require to guarantee that acid content is at 30-80w% in the esterifying kettle.The fixed bed temperature is controlled at 60-90 ℃, and the reaction kettle temperature control is at 100-140 ℃.

In this invention, the oil phase partially aqueous of esterification cat head phase-splitting is big relatively, removes thick ester jar after go to take off light processing after the rough handling.Water reclaims the organism that obtains 30-50w% after going recycle section to handle, and is circulated to reaction again in the esterifying kettle.

The present invention has realized the continuous production of 1-Methoxy-2-propyl acetate (PMA), has compared following advantage with esterification technique intermittently:

1) saved in the batch technology in and workshop section, effectively reduce acetic acid unit consumption.

2) selecting for use of fixed bed and catalyzer effectively reduces equipment corrosion speed;

3) reactive distillation has saved the band aqua, thereby has reduced to produce and polluted, and reaches cleaner production;

4) technological operation is convenient relatively.

Description of drawings

Fig. 1 is a PMA continuous production processes schematic flow sheet of the present invention.

Wherein: the 1-head tank; The 2-fixed-bed reactor; The 3-esterifying kettle; The 4-esterification column; The 5-condensing surface; The 6-phase splitter; 7-waste water storage tank; The thick ester storage tank of 8-PMA.

Embodiment

Embodiment 1:

Raw material PM and acetic acid prepared the back thorough mixing in 1: 1 in molar ratio in the 1-head tank, and raw material gets into the 2-fixed-bed reactor and carries out preliminary esterification, and fixed bed reaction heats through the outer circulation mode.The fixed bed reaction temperature is controlled at 70-80 ℃.The catalyzer that is adopted is a kind of sulfonic group strong-acid type cation exchange resin X of macromolecular structure.The recycle ratio R=3-5 that fixed bed adopts.The pre-reaction discharging gets into esterifying kettle, and still temperature temperature of reaction is controlled at 110-140 ℃.The esterifying kettle design makes and prolongs the residence time simultaneously by the reaction mass thorough mixing.The catalyzer that adopts in the esterifying kettle is a methylsulphonic acid, and catalyst levels is the 1.5w% of still liquid.Reacting coarse product is at the bottom of getting into the esterification column tower behind the heating and gasifying, and after rectifying separation, distillate condensing, phase-splitting: the upper strata obtains the ester phase; Ester major part mutually is back to the esterification cat head; Another part removes thick ester storage tank, collects the back treated light industry section of going again to take off, and ester phase reflux ratio is 2-3; Lower floor obtains water, is partly refluxed to the esterification cat head, and rest part removes recycle section after collecting, and reclaims the organism of 30-50w%, and it is returned esterifying kettle react utilization again.PMA content can reach more than the 85w% in the thick ester of the PMA that the inventive method makes.

Claims

1. a successive reaction rectifying prepares the working method of 1-Methoxy-2-propyl acetate; It is characterized in that; Comprise that step is following: the raw material propylene glycol monomethyl ether gets into one section fixed-bed reactor with after acetic acid mixed preheating in 1: 1 in molar ratio, gets into the esterifying kettle further reaction that heats up after the pre-reaction; The fixed bed reaction actuator temperature is controlled at 60-90 ℃, and the esterifying kettle temperature control is at 100-140 ℃; Catalytic amount accounts for the 0.5-3w% of total material in the said esterifying kettle, guarantees in the esterifying kettle that acid content is at 30-80w%.

2. a kind of successive reaction rectifying according to claim 1 prepares the working method of 1-Methoxy-2-propyl acetate, it is characterized in that, the recycle ratio R that said fixed-bed reactor adopt is 3-10.

3. a kind of successive reaction rectifying according to claim 1 prepares the working method of 1-Methoxy-2-propyl acetate; It is characterized in that; The catalyzer that fixed-bed reactor adopted is a strong-acid ion exchange resin, and the catalyzer that is adopted in the esterifying kettle is a kind of in sulfuric acid, methylsulfonic acid and the tosic acid.