CN104262623B - Polyphenylene sulfide material crystal vulcanized sodium rectification under vacuum dehydrating process - Google Patents

Abstract

Polyphenylene sulfide material crystal vulcanized sodium rectification under vacuum dehydrating process, by dehydrated raw material Na₂S·nH₂O, NMP, LiCl are added in vacuum rectification tower with certain mol ratio and are dehydrated, and tower pressure interior force is 20～30kPa, and heating makes Na₂S·nH₂Crystallization water removing in O, infinite reflux 1h makes vulcanized sodium be completely dissolved rear overhead extraction water, tower kettle of water content, is determined quickly using moisture titration, until tower kettle of water content, reaches designated value, stop extraction, close vavuum pump, dehydration kettle liquid is sent directly into polymerization process, the polymerisation of polyphenylene sulfide is completed, using dehydrating process tower reactor maximum temperature≤130 DEG C, rate of water loss is fast, greatly reduces the percent hydrolysis of NMP.Reduce dehydration cost, reduce solvent N methyl pyrrolidone percent hydrolysis, so as to reduce the production cost of polyphenylene sulfide.

Description

Polyphenylene sulfide material crystal vulcanized sodium rectification under vacuum dehydrating process

Technical field

The invention belongs to the method for polyphenylene sulfide synthesis material crystalline sodium sulfide dehydration, more particularly to a kind of polyphenylene sulfide original Material crystalline sodium sulfide rectification under vacuum dehydrating process, especially by crystalline sodium sulfide, solvent N-methyl pyrilidone (NMP), Auxiliary agent is added in rectifying column, the method being dehydrated under conditions of heating in vacuum.

Technical background

Polyphenylene sulfide is a kind of new high-performance engineering plastics, with high mechanical strength, high temperature resistant, corrosion-resistant, fire-retardant, hot The advantages of good stability, excellent electrical properties.

In early polyphenylene sulfide synthesis, with crystalline sodium sulfide, paracide as raw material, 1-METHYLPYRROLIDONE (NMP) it is solvent, lithium chloride is main auxiliary agent, HTHP synthesizes PPS resin.Early stage thinks anti-to PPS synthesising process research Answer system be anhydrous, therefore before polymerization, it is necessary to crystalline sodium sulfide is dehydrated, is allowed to into anhydrous sodium sulfide, then Carry out polymerisation.In the recent period with the further investigation to PPS synthesis mechanism, it is found that when reaction system contains a small amount of water, poly- to this Reaction is closed with facilitation.In appropriate H₂Na in O₂S can be dissolved in NMP, define Na₂S and NMP, H₂O mol ratio is 1:1:A kind of 1 complex compound Na₂S·NMP·H₂O, the material can promote the carrying out of polymerisation, improve product polyphenylene sulfide and receive Rate.

In Chinese patent application：Describe polyphenylene sulfide material crystal vulcanized sodium dehydrating process in 1312306, including by Aqueous vulcanized sodium, nmp solvent, auxiliary agent and alkali are added to thermal dehydration in reactor, and temperature is 180 DEG C～220 DEG C, makes many water sulphur The crystallization water for changing sodium is taken out of with gas phase.Due to the water vapour for distilling together being sent into together with solvent NMP in thermal dehydration Condensing unit, causes the waste of a large amount of solvent NMP, causes and plays a role in the reaction that substantial amounts of solvent can not be thereafter, in order to Guarantee content of the solvent thereafter in course of reaction, be necessary for the initial input of solvent is increased, and nmp solvent is costly, its Consumption and recovery loss etc. will directly influence reaction cost.Additionally, dehydration temperaturre is too high, NMP decomposed metamorphic is easily caused.

In Chinese patent application：Synthesis polyphenylene sulfide dehydrating process is described in 1454918, including will be aqueous Vulcanized sodium, nmp solvent, auxiliary agent add thermal dehydration in reactor, and dehydration subsequent process increases by a condenser, take off from reactor The steam containing a large amount of nmp solvents out, input condenser before again through rectifying by therein the overwhelming majority solvents with Water vapour is separated, and the solvent which is isolated returns reactor, and the water vapour with a small amount of solvent is input into again by normal after condenser Rule method reclaims remaining nmp solvent, so as to realize its purpose.But though the technique suffers from the drawback that have nitrogen to protect under 1. high temperature Shield, NMP are rotten still very serious so that the amount for subsequently filling into NMP increases, and affects subsequent polymerization stage.2. under nitrogen protection Dehydration, nitrogen use level increase so that equipment investment expense increases.

In Chinese patent application：Synthesis polyphenylene sulfide material crystal vulcanized sodium dewatering process side is described in 102964599 Method, including crystalline sodium sulfide, paracide, solvent NMP are added in reactor according to a certain ratio, high vacuum -0.095～- The air of 0.097MPa extraction kettle, is heated to 80～90 DEG C, controls heating rate, is dehydrated under the conditions of 140～150 DEG C. Dewatering time can be shortened while dehydration energy is reduced, but compare with the technology of the present invention due to carrying out in kettle, treating capacity Less, cost is higher.

Content of the invention

The deficiency of existing crystalline sodium sulfide dehydration technique is directed to, it is an object of the invention to provide a kind of synthesis of polyphenylene sulfide The dehydrating process of material crystal vulcanized sodium, reduces dehydration cost, reduces solvent N-methyl pyrilidone percent hydrolysis, so as to drop The production cost of oligomeric diphenyl sulfide.

The purpose of the present invention is realized by the following method：

A kind of polyphenylene sulfide material crystal vulcanized sodium rectification under vacuum dehydrating process, it is characterised in that：To crystallize sulfuration Sodium is raw material with paracide, and 1-METHYLPYRROLIDONE (NMP) is solvent, and LiCl is reaction promoter, synthesizes polyphenylene sulfide；Dehydration Na pressed by raw material₂S·nH₂O:NMP:Mol ratio between LiCl is 1:4:0.05～0.07 carries out dispensing, dehydrating process bag Include：

1) in the crystalline sodium sulfide processed stage, by Na₂S·nH₂O:NMP:Mol ratio between LiCl is 1:4:0.05 ～0.07 proportioning is added to vacuum rectification tower, and holding tower pressure interior force is 20～30kPa, and tower reactor is heated to 70～80 DEG C, makes knot The crystallization water in brilliant vulcanized sodium is all changed into free state water；

2) it is 20～30kPa to keep tower pressure interior force, and tower reactor is heated to 70～80 DEG C, and infinite reflux one hour controls reflux ratio For 1, overhead extraction water, dewatering time are 2～3h, complete dehydration；

3) tower kettle of water content, adopts moisture titration quick detection, when dehydration reaches specified water content condition, closes system, Tower reactor dehydration raffinate is directly entered in polymeric kettle and is polymerized.

Crystalline sodium sulfide can be Na₂S·9H₂O、Na₂S·5.5H₂O or Na₂S·3H₂One or more in O.

Complete in vacuum rectification tower, it is achieved that the low rate of hydrolysis of solvent N-methyl pyrilidone and low dehydration temperaturre.

Mixing kettle liquid after dehydration can be directly used for follow-up polymerization technique, on the one hand reduce the cost of synthesis procedure, On the other hand increase the rate of recovery of solvent, be that follow-up solvent recovery is cost-effective.

Advantage of the present invention：

A kind of this dehydrating process of polyphenylene sulfide synthesis material crystalline sodium sulfide, reduces dehydration cost, reduces molten Agent 1-METHYLPYRROLIDONE percent hydrolysis, so as to reduce the production cost of polyphenylene sulfide.

Specific embodiment

This polyphenylene sulfide material crystal vulcanized sodium rectification under vacuum dehydrating process, with paracide and crystalline sodium sulfide For raw material, solvent is 1-METHYLPYRROLIDONE, and polymerisation generates polyphenylene sulfide, needs to crystalline sodium sulfide before polymerisation Dehydration, controls synthetic system moisture to improve yield and the molecular weight of polyphenylene sulfide.Concrete dehydrating process bag Contain：

1) in the crystalline sodium sulfide processed stage, by Na₂S·nH₂O:NMP:Mol ratio between LiCl is 1:4:0.05 ～0.07 proportioning is added to vacuum rectification tower, and holding tower pressure interior force is 20～30kPa, and tower reactor is heated to 70～80 DEG C, makes many In water vulcanized sodium, water is all changed into free state water.

2) it is 20～30kPa to keep tower pressure interior force, and tower reactor is heated to 70～80 DEG C, and infinite reflux one hour controls reflux ratio For 1, overhead extraction water, dewatering time are 2～3h, complete dehydration.

3) tower kettle of water content, adopts moisture titration quick detection, when dehydration reaches specified water content condition, closes system, Tower reactor dehydration raffinate is directly entered in polymeric kettle and is polymerized.

4) using after above-mentioned means, rectifying and dewatering process at reduced pressure conditions, dehydration temperaturre is significantly reduced, So that solvent NMP percent hydrolysis is substantially reduced, the mixing kettle liquid after dehydration can be directly used for follow-up polymerization technique, on the one hand reduce The cost of synthesis procedure, on the other hand increases the rate of recovery of solvent, is follow-up solvent recovery is cost-effective.

5) the LiCl material for being added in the present invention, it is therefore an objective to add as auxiliary agent, on the one hand can increase polyphenylene sulfide The molecular weight of ether resin, the melt stability of raising product；On the other hand vulcanized sodium, paracide shape in solvent NMP are promoted Become homogeneous, increase polymerization rate.

Mixing kettle liquid after dehydration can be directly used for follow-up polymerization technique, on the one hand reduce the cost of synthesis procedure, On the other hand increase the rate of recovery of solvent, be that follow-up solvent recovery is cost-effective.

The process description of the present invention：

The invention discloses a kind of polyphenylene sulfide material crystal vulcanized sodium rectification under vacuum dehydrating process, synthesizes polyphenylene sulfide In ether system, with crystalline sodium sulfide and paracide as raw material, NMP is solvent, and polymerisation early stage need to be entered to crystalline sodium sulfide Row dehydration, controls the moisture in polymerization reaction system increasing molecular weight and the yield of polyphenylene sulfide, by raw material Na₂S· nH₂O, NMP, LiCl are added in vacuum rectification tower in certain proportion, by vacuum in control tower and bottom temperature to poly- Diphenyl sulfide material crystal vulcanized sodium completes rectification under vacuum processed, detects tower kettle of water content, through moisture titration, while control Bottom temperature causes tower reactor solvent NMP percent hydrolysis as low as possible.

Embodiment 1

1) in the material crystal vulcanized sodium processed stage, raw material Na is made₂S·nH₂Mol ratio between O, NMP, LiCl is 1.0:4.0:0.05, crystalline sodium sulfide is chosen as Na₂S·9H₂O, is added in vacuum rectification tower, and tower pressure interior force is 20kPa, plus Heat makes Na₂S·9H₂Water removing in O, vacustat in holding tower, overhead extraction water after infinite reflux 1h, reuse moisture titration Instrument quickly determines tower kettle of water content, until tower kettle of water content, reaches designated value, stops extraction, closes vavuum pump, by dehydration kettle liquid Polymerization process is sent directly into, the polymerisation of polyphenylene sulfide is completed, using dehydrating process tower reactor maximum temperature≤90 DEG C, Greatly reduce the percent hydrolysis of tower reactor solvent NMP.

Embodiment 2

2) in the material crystal vulcanized sodium processed stage, raw material Na is made₂S·nH₂Mol ratio between O, NMP, LiCl is 1.0:4.0:0.05, crystalline sodium sulfide is chosen as Na₂S·9H₂O, is added in vacuum rectification tower, and tower pressure interior force is 25kPa, plus Heat makes Na₂S·9H₂Water removing in O, vacustat in holding tower, overhead extraction water after infinite reflux 1h, titrated using moisture Instrument quickly determines tower kettle of water content, until tower kettle of water content, reaches designated value, stops extraction, closes vavuum pump, by dehydration kettle liquid Polymerization process is sent directly into, the polymerisation of polyphenylene sulfide is completed, using dehydrating process tower reactor maximum temperature≤102 DEG C, greatly reduce the percent hydrolysis of tower reactor solvent NMP.

Embodiment 3

3) in the material crystal vulcanized sodium processed stage, raw material Na is made₂S·nH₂Mol ratio between O, NMP, LiCl is 1.0:4.0:0.05, crystalline sodium sulfide is chosen as Na₂S·9H₂O, is added in vacuum rectification tower, and tower pressure interior force is 30KPa, plus Heat makes Na₂S·9H₂Water removing in O, vacustat in holding tower, overhead extraction water after infinite reflux 1h, reuse moisture titration Instrument quickly determines tower kettle of water content, until tower kettle of water content, reaches designated value, stops extraction, closes vavuum pump, by dehydration kettle liquid Polymerization process is sent directly into, the polymerisation of polyphenylene sulfide is completed, using dehydrating process tower reactor maximum temperature≤130 DEG C, greatly reduce the percent hydrolysis of tower reactor solvent NMP.

Comparison example 1-3

4) in the material crystal vulcanized sodium processed stage, raw material Na is made₂S·nH₂Mol ratio between O, NMP, LiCl is 1.0:4.0:0.05, crystalline sodium sulfide is chosen as Na₂S·9H₂O, is added in atmospheric distillation tower, and heating makes Na₂S·9H₂In O Water is removed, and overhead extraction water after infinite reflux 1h reuses moisture titration and quickly determines tower kettle of water content, until tower kettle of water content, Designated value is reached, stops extraction, vavuum pump is closed, dehydration kettle liquid is sent directly into polymerization process, completes the polymerization of polyphenylene sulfide Reaction, using the dehydrating process tower reactor maximum temperature at 220 DEG C or so, causes the percent hydrolysis of solvent NMP under hot conditions Increase.

Comprehensive above experimental data draws following experimental result, and crystalline sodium sulfide rectification under vacuum dehydration is compared with normal pressure dewatering process Method has following advantage：

Bottom temperature is reduced, greatly reduces the percent hydrolysis of tower reactor solvent NMP.

Reduce energy resource consumption, a large amount of saving water power usage amounts.

The generation of hydrogen sulfide is reduced under cryogenic conditions, reduces environmental pollution.

Claims (2)

1. a kind of polyphenylene sulfide material crystal vulcanized sodium rectification under vacuum dehydrating process, it is characterised in that：With crystalline sodium sulfide It is raw material with paracide, 1-METHYLPYRROLIDONE (NMP) is solvent, synthesizes polyphenylene sulfide；Dehydrated raw material presses Na₂S·nH₂O: NMP:Mol ratio between LiCl is 1:4:0.05～0.07 carries out dispensing, and dehydrating process includes：

1) in the crystalline sodium sulfide processed stage, by Na₂S·nH₂O:NMP:Mol ratio between LiCl is 1:4:0.05～ 0.07 proportioning is added to vacuum rectification tower, and holding tower pressure interior force is 20～30kPa, and tower reactor is heated to 70～80 DEG C, makes crystallization The crystallization water in vulcanized sodium is all changed into free state water；

2) it is 20～30kPa to keep tower pressure interior force, and tower reactor is heated to 70～80 DEG C, infinite reflux one hour, and control reflux ratio is 1, Overhead extraction water, dewatering time are 2～3h, complete dehydration；

3) tower kettle of water content, adopts moisture titration quick detection, when dehydration reaches specified water content condition, closes system, tower reactor Dehydration raffinate is directly entered in polymeric kettle and is polymerized.

2. polyphenylene sulfide material crystal vulcanized sodium rectification under vacuum dehydrating process according to claim 1, its feature exist In：Crystalline sodium sulfide can be Na₂S·9H₂O、Na₂S·5.5H₂One or more in O.