CN1636962A - Production method of multi-variety low-consumption plasticizer - Google Patents

Abstract

The invention relates to a new method for industrially producing PVC auxiliary plasticizers with multiple varieties, low raw materials and energy consumption by using the same set of intermittent production equipment. The plasticizer varieties that can be produced by the same set of equipment include di(2-ethyl)hexyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl terephthalate (DOTP), tri(2-ethyl)hexyl trimellitate (TOTM), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diheptyl phthalate (DHP), dioctyl adipate (DOA), dioctyl sebacate (DOS), tributyl citrate, trioctyl citrate, acetyl tributyl citrate and trioctyl acetyl citrate. The process route is: esterification reaction→dealcoholization→neutralization→refining→plasticizer products. The industrial production cycle can be shortened and the production cost of plasticizer products can be reduced.

Description

Multi-variety, low-consumption plasticizer production method

The technical field that the invention relates to is a new method for industrialized production of plasticizer products with multiple varieties, low raw material consumption and low energy consumption by using the same set of batch type plasticizer equipment.

At present, the industrial production of plasticizers at home and abroad mainly includes continuous production process and gap production process. The continuous process is characterized by stable product quality, low energy consumption, and easy automatic control of production operations, but the disadvantage is that the investment cost of equipment is large, and Limited to the production of a single plasticizer, it is impossible to convert multiple plasticizers. The traditional batch method, although capable of converting multiple types of plasticizers, suffers from high energy and raw material consumption and a long production cycle. There are two routes for producing plasticizers:

continuous process

Esterification→dealcoholization→neutralization→washing→

Refined→Plasticizer Products

traditional batch process

Esterification→neutralization→water washing→dealcoholization→

Refined→Plasticizer Products

The purpose of the present invention is to use the same set of batch reaction equipment to produce multiple types of plasticizer products, and reduce raw material and energy consumption. The basic principle is to make full use of the heat release of esterification reaction and the formation of esters in the process of synthesizing ester products 70%-80% of the excess raw material alcohol in the esterification reaction is removed by heat and the heat of the crude ester liquid, and the alcohol removed from the reaction system can be recycled to achieve the purpose of saving raw materials, reducing energy consumption and shortening the production cycle.

The specific method of the invention is to stop the heat supply of the esterification system when the conversion rate of the reactant acid (or acid anhydride) reaches 90% during the esterification reaction process of the raw material acid (or acid anhydride) and the organic alcohol, and utilize the emission of the esterification reaction Heat and crude ester generate latent heat to remove the excess alcohol added in the esterification reaction. This process can not only complete the esterification reaction process in the later stage, but also remove the excess raw material alcohol in the reaction, and at this time remove the raw material of the esterification system The water content in the alcohol is extremely small, which is conducive to the reuse of recovered alcohol and reduces the consumption of raw material alcohol. When 70-80% of excess alcohol is removed, the conversion rate of acid (or anhydride) in the esterification system is greater than 99%. The esterification reaction temperature is lowered from 250°C to 210°C to 150°C to 120°C, and then neutralized and refined to obtain plasticizer products. During the refining process, 30% to 20% of excess alcohol is removed. Completely avoid the esterification reaction, neutralization, water washing, dealcoholization and refining process routes in the traditional plasticizer production. Process route of the present invention is as follows:

Esterification→dealcoholization→neutralization→refining→plasticizer products

The chemical reaction formula that is applicable to the production plasticizer of principle of the present invention:

(1) Phthalic anhydride and alcohol

(2) trimellitic anhydride and alcohol

(3) Terephthalic acid and alcohol

(4) Citric acid and alcohol

(5) Dibasic fatty acids and alcohols

      

R in the above reaction formula can be a C ₄ -C ₁₃ aliphatic alcohol, and the carbon chain can be straight or branched; n can be 4-8.

The multi-species plasticizer that is suitable for the production of the present invention is: two (2-ethyl) hexyl phthalates (DOP), dibutyl phthalate (DBP), dioctyl terephthalate (DOTP) ), tri(2-ethyl)hexyl trimellitate (TOTM), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diheptyl phthalate (DHP), dioctyl adipate (DOA), dioctyl sebacate (DOS), tributyl citrate, trioctyl citrate, acetyl tributyl citrate, acetyl trioctyl citrate, etc. .

The esterification catalyst suitable for the present invention is non-sulfuric acid, aprotic acid catalyst: mainly tetrabutyl titanate, tetraisopropyl titanate, tetrabutyl titanate and tetraisopropyl titanate composite catalyst, solid acid catalyst have Stannous oxide, stannous oxalate, aluminum oxide, sodium metaaluminate, solid superacid.

The esterification raw material suitable for industrial production of the present invention is an organic acid or anhydride: phthalic anhydride, trimellitic anhydride, terephthalic acid, citric acid, adipic acid, sebacic acid, glutaric acid; the esterification reaction raw material alcohol is : n-Butanol, 2-Ethyl Ethanol, n-Heptanol, n-Decanol, n-Nonyl Isoheptanol, Isodecyl Alcohol, Isononanol.

Example 1 Synthesis of general-purpose plasticizer di(2-ethyl)hexyl phthalate (DOP)

Add 6.5 tons of phthalic anhydride, 14.5 tons of 2-ethylhexanol, and 5KG of catalyst tetraisopropyl titanate in a stainless steel esterification reactor with a packed tower and a condenser with a batch volume of ^30M3 . Carbon 5KG, heated from room temperature to 160 ℃ ~ 230 ℃ for esterification reaction, after 3 hours of reaction, measure the acid value of the esterification reaction liquid 5.0mgKOH/g, open the vacuum system, dealcoholization under vacuum degree -0.72 ~ -0.85Mpa , after removing 2.5 tons of 2-ethylhexanol from the esterification reaction system, the temperature of the reaction solution is 160 ° C ~ 110 ° C, the acid value of the esterified crude ester is reduced to 0.2 mgKOH/g, and it is refined by neutralization and steam stripping for 2.5 hours Finally, 17.08 tons of DOP finished products were obtained. Ester content of finished product: more than 99%; density (p): 0.982-0.988g/cm ³ ; heat loss (125°C, 2 hours): 0.09%; color (APHA): 15; acid value of finished product: 0.02mgKOH/g ; Flash point (open cup method): 195°C, volume resistivity: 5×10 ¹¹ (ΩM), after heating (180°C/2h) color: 40 (APHA); after heating (180°C/2h) acid value: 0.06mgKOH/g.

Example 2 Synthesis of a new 105°C grade high temperature resistant plasticizer tris(2-ethyl)hexyl trimellitate (TOTM)

In a 500ml glass three-neck flask equipped with stirring, thermometer, condenser, and alcohol-water separator, add 0.5mol (96.0g) of trimellitic anhydride, 2.5mol (325.0g) of 2-ethylhexanol, and use 2.0g Solid superacid _SO42- / _ZrO2As esterification catalyst, add 2.0g activated carbon, after esterification reaction under 210 ℃ for 3h, the conversion rate of trimellitic anhydride is 95.8%, and the color ^and luster of crude ester is 80 (APHA ), switch to vacuum conditions, take off part of the excess 2-ethylhexanol at -0.95Mpa, after the reaction temperature is dropped to 150°C, separate the catalyst, the catalyst can be recycled, and then use 3% NaOH solution And crude ester, after refining, obtain trimellitic (2-ethyl) hexyl ester (TOTM) product. The acid value of the finished product is 0.056mgKOH/g, the color is 70 (APHA), the ester content is 99.6%, the flash point is 245°C, and the volume electric coefficient is 2.0×10 ¹² (ΩM). The product yield after refining is 98.2%, and the selectivity of the reaction is 98.0%.

Example 3 Synthesis of 95°C special plastic additive di(2-ethyl)hexyl terephthalate (DOTP)

In a 500ml glass three-necked flask equipped with stirring, a thermometer, a condenser, and an alcohol-water separator, add the esterification raw material 2-ethylhexanol to terephthalic acid in a molar ratio of 3.5mol: 1mol, and add the total raw material Add 0.3% tetrabutyl titanate catalyst, add 1.0 g of activated carbon, and react esterification reaction at 220 ° C for 6.5 hours. The acid value at the end point of the esterification of the crude ester is 0.5 mgKOH/g, and the color of the crude ester is 120 ( APHA), after removing part of the excess alcohol, then after neutralization and stripping, the acid value of the finished ester product is 0.07mgKOH/g, the color is 70 (APHA), the ester content is 99.6%, the flash point is 218 ° C, the volume The electrical coefficient is 1.0×10 ¹² (ΩM), the refractive index n ²⁵ _D is 1.4687, the product yield after refining is 98.2%, and the reaction selectivity is 98.0%.

Example 4 synthesis of special cold-resistant plasticizer diisononyl adipate

Add 200g of adipic acid, 500g of isononyl alcohol, and 1g of activated carbon to a 1000ml esterification reaction device with stirring, thermometer, condenser, and alcohol-water separator, stir and heat to 180°C, then add tetraisopropyl titanate Esters, then heated to 220°C, measured the acid value of the esterification reaction solution for 3 hours to 2.5mgKOH/g, dealcoholized under vacuum conditions, recovered 84.3g of isononyl alcohol, and added 5% Na ₂ CO at the liquid temperature of 100°C ₃ solution, after separating the water phase, measure the acid value of the crude ester at 0.021mgKOH/g, add 0.5g of activated carbon, 0.5g of magnesium oxide, and strip it for 0.5h under the condition of vacuum degree of -0.9Mpa, filter the ester solution after cooling, and obtain Diisononyl diacid product 540.5g, color 25 (APHA), flash point 195°C, acid value 0.05mgKOH/g.

Claims (4)

1. Utilize the same set of equipment of plasticizer to be multi-kind, low raw material consumption, a kind of method of industrialized production plasticizer product of low energy consumption, the plasticizer kind that adopts the present invention to produce is: phthalic acid two (2- Ethyl)hexyl ester (DOP), dibutyl phthalate (DBP), dioctyl terephthalate (DOTP), tris (2-ethyl) hexyl trimellitate (TOTM), phthalate Diisononyl dicarboxylate (DINP), diisodecyl phthalate (DIDP), diheptyl phthalate (DHP), dioctyl adipate (DOA), dioctyl sebacate ( DOS), tributyl citrate, trioctyl citrate, acetyl tributyl citrate, acetyl trioctyl citrate, etc. 2. The raw material organic alcohol is a C ₄ ~ C ₁₃ fatty alcohol compound, and the carbon chain in the molecular structure can be straight or branched; the organic acid anhydride is phthalic anhydride and trimellitic anhydride; the organic acid is terephthalic acid , citric acid; dibasic acid is adipic acid, sebacic acid, glutaric acid. 3. The esterification catalyst used in the present invention is tetra-n-butyl titanate, tetraisopropyl titanate, tetrabutyl titanate and tetraisopropyl titanate composite catalyst, stannous oxide, aluminum oxide, sodium metaaluminate , Solid super acid. 4. The technology of the present invention is a batch-type esterification production method, and the process features are: esterification, dealcoholization, neutralization, and refining.