Preparation process of cyclic phosphonate CU flame retardant

Abstract

The invention belongs to the technical field of synthesis of organic phosphorus functional compounds, and particularly relates to a preparation process of a cyclic phosphonate CU flame retardant, which comprises the following steps: adding TMP (trimethylolpropane) and trimethylolpropane into a synthesis kettle, carrying out transesterification at normal pressure and 80-160 DEG C, distilling out a byproduct methanol while reacting, reacting for 12 hours to obtain an intermediate product TMPP (trimethylolpropane), and separating the intermediate product TMPP to obtain the cyclic phosphonate CU flame retardant. The method comprises the following steps: recovering methanol, returning the recovered methanol to a TMP esterification kettle for mechanical application, adding DMMP into a synthesis kettle, carrying out substitution and rearrangement reaction at 160-220 DEG C for 8 hours to obtain a crude product, carrying out reduced pressure distillation on the crude product at 160-220 DEG C under the vacuum degree of 0.09-0.10 MPa, and evaporating to remove a front fraction to obtain a CU product, the main component of the front fraction being unreacted DMMP, and recovering the unreacted DMMP for mechanical application in substitution and rearrangement reaction; the whole conversion efficiency of raw materials is improved, meanwhile, recycling of by-products and unreacted raw materials is achieved, raw material waste is reduced, the raw material cost of production is reduced, and the state of the whole production process is more controllable and the product quality is stable through step-by-step temperature, pressure and other condition management and control.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic phosphorus functional compound synthesis, and particularly relates to a preparation process of a cyclic phosphonate CU flame retardant. BACKGROUND

[0002] The CU compound is a kind of phosphorus-containing organic derivative, and has wide application potential in the fields of flame retardant additives and functional plasticizers of high polymer materials due to a high proportion of phosphorus elements.

[0003] At present, the synthesis of the CU compound in the prior art is mostly performed by using a one-step process, that is, a plurality of raw materials are directly mixed and reacted. However, the process has obvious technical defects. On the one hand, the ester exchange reaction between the raw materials is difficult to fully proceed, the conversion efficiency of the raw materials is low, and the output efficiency of the product is limited. On the other hand, the by-products and unreacted raw materials generated in the reaction process are not effectively recycled, which not only increases the raw material cost of production, but also requires additional resources to treat the waste materials, which does not meet the demand of green production. Meanwhile, the reaction condition control mode of the existing process is relatively single, lacks fine parameter control, and is easy to cause great fluctuations in quality indexes such as the appearance color, component purity and the like of the product, and cannot stably adapt to the strict performance requirements of high-end materials on the additives. SUMMARY

[0004] In order to solve the above problems, the application provides a preparation process of a cyclic phosphonate CU flame retardant, which improves the overall conversion efficiency of the raw materials, realizes the recycling of by-products and unreacted raw materials, reduces the waste of raw materials, reduces the raw material cost of production, and realizes step-by-step control of temperature, pressure and the like, so that the state of the entire production process is more controllable, and the product quality is stable.

[0005] In order to realize the above functions, the technical scheme adopted by the application is as follows: a preparation process of a cyclic phosphonate CU flame retardant, each step in the preparation process is performed under pure nitrogen protection, and the process comprises the following steps: (1) Raw material pretreatment: the trimethylolpropane is put into a material kettle, heated to 100 DEG C, melted under normal pressure, stirred at a speed of 60 r / min, and kept for 30 min until the raw material is completely melted into a transparent liquid, then transferred to a batching kettle, added with equimolar trimethoxy phosphorus, stirred for 20 min, mixed uniformly, and reserved; (2) transesterification reaction: the mixture is transferred to a distillation kettle, after sealing the kettle body, the temperature is raised to 80 DEG C at a rate of 5 DEG C / min, under normal pressure, the stirring is started, the stirring rate is 50r / min, 80 DEG C is kept for 2h, the byproduct methanol is collected through the kettle top distillation device, the temperature is raised to 120 DEG C at a rate of 5 DEG C / h, and kept for 4h, the methanol is continuously collected, the temperature is raised to 150 DEG C, and kept for 6h, until the methanol distillation amount is less than 0.5kg / h, the distillation is stopped, the collected methanol is stored in a storage tank, and is returned to the TMP esterification kettle for recycling as raw material, after the reaction is completed, the kettle material is intermediate product TMPP; (3) substitution rearrangement reaction: dimethyl methylphosphonate is added to the distillation kettle, the stirring rate is adjusted to 80r / min, the temperature is raised to 160 DEG C at a rate of 10 DEG C / min, and kept for 2h, the temperature is raised to 200 DEG C, and kept for 6h, the negative pressure in the kettle is kept at 0.02MPa throughout the process, and a small amount of low-boiling substance is discharged, after the reaction is completed, the kettle material is CU crude product; (4) vacuum distillation: vacuum is extracted to a vacuum degree of 0.09MPa, the temperature is raised to 120 DEG C at a rate of 5 DEG C / min, the front fraction is collected, the temperature is raised to 200 DEG C, the vacuum degree is kept at 0.10MPa, and kept for 4h, and the CU product is collected; (5) recovery and reuse: the collected front fraction is stored in a storage tank, and is reused in the substitution rearrangement reaction of step (3).

[0006] Compared with the prior art, the above scheme has the beneficial effects as follows: 1. Through fine step-by-step process parameter control, the stability of core quality indexes such as product appearance and component purity is effectively improved, so that the product can better adapt to the strict performance requirements of high-end materials on additives; 2. The step-by-step temperature, pressure and other condition control makes the state of the whole production process more controllable, the production rhythm more stable, facilitates the realization of large-scale batch production, and improves the repeatability and overall efficiency of production 3. The overall conversion efficiency of raw materials is improved, and the recycling of byproducts and unreacted raw materials is realized, which reduces raw material waste and reduces the raw material cost of production, in line with the modern production concept of green and low carbon. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 The process flow chart of the preparation process of the cyclic phosphonate ester CU flame retardant. DETAILED DESCRIPTION

[0008] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0009] The present application relates to a preparation process of cyclic phosphonate CU flame retardant, each step in the preparation process is carried out under the protection of pure nitrogen, which comprises the following steps: (1) raw material pretreatment: the trimethylolpropane is put into the material melting kettle, heated to 100 DEG C, melted under normal pressure, the stirring speed is 60 r / min, the temperature is kept for 30 min until the raw material is completely melted into transparent liquid, transferred to the batching kettle, the same molar amount of trimethoxy phosphorus is added, stirred for 20 min, mixed uniformly, and standby; (2) ester exchange reaction: the mixture is transferred to the distillation kettle, the kettle body is sealed, the temperature is raised to 80 DEG C at a rate of 5 DEG C / min, the stirring is started under normal pressure, the stirring speed is 50 r / min, the temperature is kept at 80 DEG C for 2 h, the by-product methanol is collected through the kettle top distillation device, the temperature is raised to 120 DEG C at a rate of 5 DEG C / h, the temperature is kept for 4 h, the methanol is continuously collected, the temperature is raised to 150 DEG C, the temperature is kept for 6 h, until the amount of methanol distillation is less than 0.5 kg / h, the distillation is stopped, the collected methanol is stored in the storage tank, and is returned to the TMP esterification kettle for recycling as raw material, after the reaction is completed, the kettle material is the intermediate product TMPP; Reaction formula:

[0010] (the molar ratio of raw material is 1:1, and the theoretical generation of TMPP is 162 kg per mole of raw material) (3) substitution rearrangement reaction: the same molar amount of dimethyl methylphosphonate as trimethylolpropane is added to the distillation kettle, the stirring speed is adjusted to 80 r / min, the temperature is raised to 160 DEG C at a rate of 10 DEG C / min, the temperature is kept for 2 h, the temperature is raised to 200 DEG C, the temperature is kept for 6 h, the negative pressure in the kettle is kept at 0.02 MPa throughout the process, a small amount of low-boiling substance is discharged, after the reaction is completed, the kettle material is the CU crude product; Reaction formula:

[0011] (the molar ratio of raw material is 1:1, and the theoretical generation of CU is 286 kg per mole of raw material) (4) vacuum distillation: vacuum to 0.09 MPa, raise the temperature to 120 DEG C at a rate of 5 DEG C / min, collect the front fraction, raise the temperature to 200 DEG C, keep the vacuum degree at 0.10 MPa, keep the temperature for 4 h, and collect the CU product; (5) recovery and application: the collected front fraction is stored in the storage tank and applied to the substitution rearrangement reaction of step (3). Embodiment

[0012] A preparation process of cyclic phosphonate CU flame retardant, each step in the preparation process is carried out under pure nitrogen protection, which comprises the following steps: (1) raw material pretreatment: 134 kg of trimethylolpropane is put into a 4 m³ material melting kettle, melted at 100 ℃ / normal pressure, and then transferred to a 6.3 m³ batching kettle, 124 kg of TMP is added, and stirred for 20 min for uniform mixing; (2) ester exchange reaction: the mixed material is transferred to a 5 m³ ester exchange distillation kettle, 80 ℃ is kept for 2 h, then heated to 120 ℃ for 4 h, and 150 ℃ for 6 h, 96 kg of methanol is collected, and 162 kg of TMPP is obtained; (3) substitution rearrangement reaction: 124 kg of DMMP is added to the kettle, 160 ℃ is kept for 2 h, then heated to 200 ℃ for 6 h, and 286 kg of CU crude product is obtained; (4) vacuum distillation: the crude product is transferred to a substitution rearrangement distillation kettle, 6.2 kg of DMMP is collected at 120 ℃ under 0.09 MPa vacuum, and 279.8 kg of CU finished product is collected at 200 ℃ / 0.10 MPa; (5) recovery and reuse: the collected DMMP is stored in a storage tank and reused in the substitution rearrangement reaction of step (3); (6) test results: the finished product is colorless transparent liquid, the phosphorus content is 25.1 wt%, the acid value is 6 mgKOH / g, the viscosity is 120000 cps, and the color value is 80 Pt-Co, which meets all the indicators.

[0013] Product index test results: Appearance: colorless transparent liquid; phosphorus content: 25.1 wt%; viscosity: 120000 cps; Acid value: 6 mgKOH / g; DMMP: 0.3%, TMPP: 0.05%.

[0014] Comparative Example 1 The raw materials, feeding ratio and main equipment of this comparative example and the example are consistent, the core difference is that high-purity nitrogen protection is not used throughout the reaction.

[0015] Product index test results: Appearance: light yellow viscous liquid; phosphorus content: 20.8 wt%; viscosity: 135000 cps; Acid value: 7.2 mgKOH / g; DMMP: 0.45%, TMPP: 0.08%.

[0016] CU product index Item Indicator Appearance Transparent viscous liquid Phosphorus content (wt, %) ≥20.5 Acid value, mgKOH / g ≤8 Viscosity (25°C), cps ≤150000 Color value (Pt-Co) ≤100 DMMP, % ≤0.5 TMPP, % ≤0.1 The above describes the present application and its embodiments, which are not limited, and the examples shown are only one of the embodiments of the present application, and are not limited in practice. In general, if a person skilled in the art is inspired, without departing from the purpose of the present application, without creative design, similar examples of the technical solution should belong to the protection scope of the present application.

Claims

1. A preparation process for a cyclic phosphonate CU flame retardant, characterized in that, Each step of the preparation process is carried out under the protection of pure nitrogen, including the following steps: (1) Raw material pretreatment: Trimethylolpropane is added to the melting tank and melted at 100°C and normal pressure. Then it is transferred to the batching tank and mixed evenly with an equimolar amount of TMP. (2) Transesterification reaction: The mixture is transferred to a distillation vessel, and the reaction is carried out by gradient heating. Methanol is collected by distillation and returned to the TMP esterification vessel for reuse to obtain the intermediate product TMPP. (3) Substitution rearrangement reaction: Add DMMP in equimolar amounts to trimethylolpropane to the system in step (2), and react with gradient temperature to obtain crude CU product; (4) Vacuum distillation: Evacuate to a vacuum degree of 0.09 MPa, raise the temperature to 120°C at 5°C / min, collect the fore fraction, raise the temperature to 200°C, maintain a vacuum degree of 0.10 MPa, keep warm for 4 hours, and collect the Cu product. (5) Recovery and reuse: The collected fore fraction is stored in a storage tank and reused in the substitution rearrangement reaction in step (3).

2. The preparation process of the cyclic phosphonate CU flame retardant according to claim 1, characterized in that, The gradient heating reaction in step (2): Gradient 1: Keep warm at 80℃ for 2 hours, and start collecting the byproduct methanol through the top distillation device; Gradient 2: Increase the temperature to 120℃ at a rate of 5℃ / h, hold for 4h, and continuously collect methanol; Gradient 3: Increase the temperature to 150℃ and hold for 6 hours until the methanol distillation rate is <0.5 kg / h, then stop distillation.

3. The preparation process of the cyclic phosphonate CU flame retardant according to claim 1, characterized in that... The gradient heating reaction in step (3): Gradient 1: Increase the temperature to 160℃ at a rate of 10℃ / min and hold for 2 hours; Gradient 2: Heat to 200℃, hold for 6 hours, maintain negative pressure of 0.02MPa inside the vessel throughout the process, and discharge trace amounts of low-boiling substances.

4. The preparation process of the cyclic phosphonate CU flame retardant according to claim 1, characterized in that, The stirring rate of the mixing tank in step (1) is 60 r / min, and the stirring time of the batching tank is 20 min.

5. The preparation process of the cyclic phosphonate CU flame retardant according to claim 1, characterized in that, In step (4), the fore fraction is mainly unreacted DMMP.

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