CN105037161A - A kind of continuous method for synthesizing cyclohexane polyacid ester - Google Patents

Abstract

The invention relates to a method for synthesizing cyclohexane polybasic acid ester, which comprises the following steps: adding benzene polycarboxylic acid or anhydride thereof and alcohol into a stirring tank reactor, adding an acid catalyst, heating to 200-240 ℃, reacting until the acid value is lower than 0.2mgKOH/g, then directly feeding the crude product of the esterification reaction into a trickle bed reactor for hydrogenation reaction, wherein the hydrogen pressure is 40-100 bar, the temperature is 70-250 ℃, the catalyst is porous oxide loaded with VIIIB metal, adding alkali to neutralize and remove acid, distilling or evaporating to remove alcohol, removing byproducts, filtering and deashing after the reaction is finished, and obtaining the cyclohexane polybasic acid ester. The method does not need a purification step after the esterification reaction generates a crude product, takes excessive alcohol as a solvent for subsequent hydrogenation reaction, and carries out purification steps of removing alcohol, removing acid, filtering and the like after the hydrogenation reaction so as to save time and energy. Meanwhile, the invention selects the alumina-magnesia composite oxide as the catalyst carrier and selects palladium or ruthenium as the metal catalyst, so that the hydrogenation rate of the benzene ring reaches more than 99.9 percent.

Description

A kind of continuous method for synthesizing cyclohexane polyacid ester

technical field

The invention relates to a method for synthesizing cyclohexane polybasic acid ester, in particular to a method for continuously esterifying and reducing raw materials to obtain cyclohexane polybasic acid ester.

Background technique

In recent years, it has been discovered that phthalate plasticizers may be harmful to human health. They can enter the human body through drinking, eating, skin contact and breathing. Long-term exposure to such compounds can cause damage to the peripheral nervous system and cause multiple neuropathy Inflammation and dysesthesia, numbness and other symptoms. The World Health Organization also pointed out that the hydrolysis metabolites of phthalates (especially short-chain phthalates) in the human body are likely to affect the metabolism and reproductive functions in organs, so they belong to environmental hormones and have biological functions. Cumulative. Therefore, many countries and regions (including the European Union, the United States, Japan and Taiwan) have extremely strict regulations on the use of phthalate plasticizers, and relevant regulations can be widely found in products for infants (under 3 years old) and pregnant women , food, and medical supplies are expected to become more stringent. Therefore, the development of environmentally friendly and safe plasticizers that can replace traditional phthalates has become an imperative trend in related industries around the world.

There are many non-phthalate plasticizers on the market, but each alternative plasticizer has its own limitations and disadvantages, and there are only a few that can completely replace phthalate plasticizers. At present, the plasticizer with the greatest potential for substitution is 1,2-cyclohexanedicarboxylic acid dibasic acid ester plasticizer. This type of plasticizer uses butadiene and maleic anhydride as raw materials, synthesizes tetrahydrophthalic anhydride through Diels-Alder addition reaction, and then hydrogenates to synthesize hexahydrophthalic anhydride, and finally hexahydrophthalic anhydride It can be synthesized by esterification reaction between acid anhydride and alcohol. No phthalate residue is the advantage of this technology, but the biggest disadvantage of this technology is the need to rely on butadiene raw materials that are in high demand and fluctuate in price.

The current regulations stipulate that the content of phthalates in plastic products for infants and young children must be below 1000ppm, and the content of general phthalates plasticizers in PVC products is estimated to be about 30~70%. To make phthalic acid into qualified plasticizer by hydrogenation method, the hydrogenation rate of benzene ring must be at least greater than 99.9%. In other words, the benzene ring hydrogenation rate of phthalates must be at least greater than 99.9%, so that the 1,2-cyclohexanedicarboxylic acid dibasic ester plasticizer product can meet the current regulations.

DINCH (diisononyl 1,2-cyclohexanedicarboxylate) is the primary plasticizer of choice after the European Union bans the use of phthalate plasticizers in plastic products and children's toys that are in close contact with the human body. DINCH is also an excellent general-purpose plasticizer in non-toxic applications. So far, all countries in the world have approved it to be in contact with food, and the PVC children's toys and related plastic products made of this product comply with the European Union's 1999/815/EC environmental protection resolution.

The existing technology must purify the diisononyl phthalate and then hydrogenate it. The steps are cumbersome, the energy consumption is large, and the conversion rate of diisononyl phthalate can only reach 99%.

Contents of the invention

The purpose of this invention is to provide a kind of benzene polycarboxylic acid or its acid anhydride continuous esterification, reduction, the method for the synthetic cyclohexane polybasic acid ester of high conversion rate, and its hydrogenation conversion rate reaches more than 99.9%.

To achieve the above object, the present invention adopts the following technical solutions:

The invention discloses a method for synthesizing cyclohexane polybasic acid ester. After esterifying benzene polycarboxylic acid or its anhydride and alcohol without aftertreatment, the crude product containing alcohol is directly catalytically hydrogenated to obtain cyclohexane polybasic acid ester.

Further, the benzene polycarboxylic acid is phthalic acid, isophthalic acid, terephthalic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid or 1,2,3 -Benzenetricarboxylic acid.

Further, the esterification step is: put benzene polycarboxylic acid or its anhydride and alcohol with a molar ratio of 1:2.2~3.5 into a stirred tank reactor, and the reactor uses an alcohol-water reflux stratification device, and then adds an acid catalyst Afterwards, heat to 200~240°C and react until the acid value is lower than 0.2mgKOH/g.

Further, the alcohol is at least one of C1~C30 alkyl alcohol, C3~C30 cycloalkyl alcohol and C1~C30 alkoxy alkyl alcohol.

C1~C30 alkyl alcohols are alkyl alcohols with 1~30 carbon atoms and straight or branched carbon chains.

C3~C30 cycloalkyl alcohols are alcohols with 3~30 carbon atoms containing one or more cycloalkyl groups (cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.), and the carbon chain is straight or Branched.

C1~C30 alkoxy alkyl alcohols are alcohols with 2~30 carbon atoms, containing one or more alkoxy groups (methoxy, ethoxy, etc.), and the carbon chain is straight or branched.

Further, the alcohol is at least one of C2~C20 straight chain or branched chain alkyl alcohols.

Further, the alcohol is at least one of butanol, isooctyl alcohol, isononyl alcohol and isodecyl alcohol.

Further, the step of catalytic hydrogenation is as follows: directly feed the crude product of the esterification reaction to a trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 40-100 bar, the temperature is 70-250 ° C, and the catalyst is a metal of group VIII B porous oxides.

Further, the Group VIIIB metal is at least one of ruthenium, rhodium and palladium.

Further, the porous oxide is alumina-magnesia composite oxide.

Further, post-treatment after catalytic hydrogenation: adding alkali to neutralize and remove acid, distilling or evaporating to remove alcohol and by-products, and filtering for deashing.

Further, add benzene polycarboxylic acid or its anhydride and alcohol with a molar ratio of 1:2.2~3.5 into the stirred tank reactor, and the reactor uses an alcohol-water reflux stratification device, then adds an acid catalyst and heats to 200~240°C , react until the acid value is lower than 0.2mgKOH/g, then directly feed the crude product of the esterification reaction containing alcohol to the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 40~100bar, the temperature is 70~250℃, the catalyst It is a porous oxide loaded with Group VIIIB metals. After the reaction, add alkali to neutralize acid, distill or evaporate alcohol, remove by-products, filter and deash to obtain cyclohexane polybasic acid ester.

The present invention has the following beneficial effects:

The present invention integrates the esterification and hydrogenation process of cyclohexane polybasic acid ester, reduces complicated and energy-consuming purification procedures, and achieves the purpose of saving energy and reducing production costs. After the esterification reaction generates a crude product, no purification step is performed. Excess alcohol is used as the solvent for the subsequent hydrogenation reaction, and purification steps such as alcohol removal, acid removal, and filtration are performed after the hydrogenation reaction to save time and energy. At the same time, the present invention selects alumina-magnesia composite oxide as the catalyst carrier, selects palladium or ruthenium as the metal catalyst, and makes the hydrogenation rate of the benzene ring reach more than 99.9%. Moreover, the esterification equipment of the present invention adopts a continuous stirred tank reactor and an alcohol-water reflux stratification device, and the hydrogenation equipment adopts a trickle bed reactor, and the equipment occupies a small area and is easy to operate. The water generated by the esterification reaction is quickly removed, and part of the alcohol is refluxed for reaction.

Detailed ways

The present invention will be further described below in conjunction with specific embodiment:

The preparation method of catalyst used in following examples is as follows:

420g of magnesium nitrate hexahydrate [Mg (NO ₃ ) ₂ . 6H ₂ O] and 465g aluminum nitrate nonahydrate [Al(NO ₃ ) ₃ . 9H ₂ O] was dissolved in 6000mL of deionized water, then an aqueous solution containing sodium carbonate was added for coprecipitation, and fully stirred and mixed at 60°C, and 300g of alumina was added to stir and then filtered, and the obtained filter cake was washed with water and dried at 110°C dry to obtain alumina-magnesia composite oxide powder.

Take 300g of alumina-magnesia composite oxide powder and 60g of molding agent and adhesive, go through kneading and extrusion molding steps, and calcined at 450°C for 4 hours to obtain a cylindrical porous oxide carrier, of which magnesia accounts for about 12wt%, the cylindrical porous oxide carrier was crushed, sieved and sized to obtain particles with a mesh number of 20-30.

Take about 30g of the above particles, use the impregnation solution containing RuCl ₃ to implant ruthenium metal on the surface of the carrier by the incipient wetness method, and then calcined at 450°C for 4 hours to obtain the X catalyst, in which the ruthenium accounts for 5wt%, and the false density is 0.649 g/cm ³ .

Take about 30g of the above particles, use the impregnation solution containing PdCl ₂ to implant palladium metal on the surface of the carrier by the incipient wetness method, and then calcined at 450°C for 4 hours to prepare the Y catalyst, in which palladium accounts for 2wt%, and the bulk density is It is 0.546g/cm ³ .

Example 1

Add phthalic anhydride and isononyl alcohol with a molar ratio of 1:2.5 into the stirred tank reactor, and the reactor uses an alcohol-water reflux layering device, and then adds an acid catalyst and heats to 220°C for esterification reaction, as shown in the formula Shown in I, react to the acid value of diisononyl phthalate crude product below 0.2mgKOH/g, gained diisononyl phthalate crude product contains excess isononyl alcohol (containing about 85% phthalate diisononyl formate and approximately 15% isononyl alcohol). Take 3.9g of X catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, as shown in formula I, the hydrogen pressure is 50bar, the temperature is 70°C, the hydrogen flow rate is 100mL/min, the esterification reaction crude product flow rate is 4.5mL/h, hydrogen and phthalate The molar ratio of diisononyl formate is about 28:1. After the reaction, add alkali to neutralize and remove acid (acid catalyst for esterification reaction), distill off alcohol and by-products, filter and deash to obtain 1,2-cyclohexanedicarboxylate diisononyl.

Analyze the concentration of residual benzene rings in the product with an ultraviolet-visible light spectrometer. The absorption peak of the benzene ring is at a wavelength of 275nm. Diisononyl phthalate has strong absorption, and diisononyl 1,2-cyclohexanedicarboxylate has no absorption. , prepare different concentrations of diisononyl phthalate/diisononyl 1,2-cyclohexanedicarboxylate, make a calibration line, and calculate the concentration and hydrogenation rate of diisononyl phthalate (hydrogenation Rate = 1-concentration of residual diisononyl phthalate %).

Analysis results show that the concentration of diisononyl phthalate is about 1000ppm, that is, the hydrogenation rate of benzene ring reaches 99.90%.

Formula I

Example 2

Add phthalic anhydride and isononyl alcohol with a molar ratio of 1:2.5 into the stirred tank reactor. The reactor uses an alcohol-water reflux layering device, and then adds an acid catalyst and heats it to 220°C for esterification reaction. The acid value of the crude diisononyl phthalate is lower than 0.2 mgKOH/g, and the obtained crude diisononyl phthalate contains excess isononyl alcohol. Take 3.9g of X catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 50bar, the temperature is 100°C, the hydrogen flow rate is 100mL/min, the esterification reaction crude product flow rate is 4.5mL/h, the hydrogen and diisononyl phthalate The molar ratio is about 28:1. After the reaction, add alkali to neutralize and remove acid, distill alcohol and by-products, filter and deash to obtain 1,2-cyclohexanedicarboxylic acid diisononyl.

The concentration of residual benzene rings in the product was analyzed by ultraviolet-visible light spectrometer, and the analysis results showed that the concentration of diisononyl phthalate was about 500 ppm, that is, the hydrogenation rate of benzene rings reached 99.95%.

Example 3

Add phthalic anhydride and isononyl alcohol with a molar ratio of 1:2.5 into the stirred tank reactor. The reactor uses an alcohol-water reflux layering device, and then adds an acid catalyst and heats it to 220°C for esterification reaction. The acid value of the crude diisononyl phthalate is lower than 0.2 mgKOH/g, and the obtained crude diisononyl phthalate contains excess isononyl alcohol. Take 3.9g of X catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 50bar, the temperature is 120°C, the hydrogen flow rate is 100mL/min, the crude product flow rate of the esterification reaction is 4.5mL/h, the hydrogen and diisononyl phthalate The molar ratio is about 28:1. After the reaction, add alkali to neutralize and remove acid, evaporate to remove alcohol and by-products, filter and deash, and obtain 1,2-cyclohexanedicarboxylic acid diisononyl.

The concentration of residual benzene rings in the product was analyzed by ultraviolet-visible light spectrometer, and the analysis results showed that the concentration of diisononyl phthalate was about 400 ppm, that is, the hydrogenation rate of benzene rings reached 99.96%.

Example 4

Add phthalic anhydride and isononyl alcohol with a molar ratio of 1:2.5 into the stirred tank reactor. The reactor uses an alcohol-water reflux layering device, and then adds an acid catalyst and heats it to 220°C for esterification reaction. The acid value of the crude diisononyl phthalate is lower than 0.2 mgKOH/g, and the obtained crude diisononyl phthalate contains excess isononyl alcohol. Take 3.9g of X catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 100bar, the temperature is 70 ° C, the hydrogen flow rate is 100mL/min, the flow rate of the crude product of the esterification reaction is 4.5mL/h, the hydrogen and diisononyl phthalate The molar ratio is about 28:1. After the reaction, add alkali to neutralize and remove acid, evaporate to remove alcohol and by-products, filter and deash, and obtain 1,2-cyclohexanedicarboxylic acid diisononyl.

The concentration of residual benzene rings in the product was analyzed by ultraviolet-visible light spectrometer, and the analysis results showed that the concentration of diisononyl phthalate was about 400 ppm, that is, the hydrogenation rate of benzene rings reached 99.96%.

Example 5

Add phthalic acid and isononyl alcohol with a molar ratio of 1:2.2 into the stirred tank reactor. The reactor uses an alcohol-water reflux layering device, and then adds an acid catalyst and heats to 200°C for esterification reaction until the acid The price is lower than 0.2mgKOH/g. Take 3.3g of Y catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 50bar, the temperature is 180 ° C, the hydrogen flow rate is 100mL/min, the flow rate of the crude product of the esterification reaction is 4.5mL/h, the hydrogen and diisononyl phthalate The molar ratio is about 28:1. After the reaction, add alkali to neutralize and remove acid, distill alcohol and by-products, filter and deash to obtain 1,2-cyclohexanedicarboxylic acid diisononyl.

The concentration of residual benzene rings in the product was analyzed by ultraviolet-visible light spectrometer, and the analysis results showed that the concentration of diisononyl phthalate was about 1000 ppm, that is, the hydrogenation rate of benzene rings reached 99.90%.

Example 6

Add isophthalic acid and isooctyl alcohol with a molar ratio of 1:3 into the stirred tank reactor, and the reactor uses an alcohol-water reflux layering device, then adds an acid catalyst and heats to 240°C for esterification reaction, and reacts until the acid The price is lower than 0.2mgKOH/g. Take 3.3g of Y catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 50bar, the temperature is 210 ° C, the hydrogen flow rate is 100mL/min, the flow rate of the crude product of the esterification reaction is 4.5mL/h, the hydrogen and diisooctyl isophthalate The molar ratio is about 28:1. After the reaction, add alkali to neutralize and remove acid, distill to remove alcohol and by-products, filter and deash to obtain 1,3-diisooctyl cyclohexanedicarboxylate.

The concentration of residual benzene rings in the product was analyzed by ultraviolet-visible light spectrometer, and the analysis results showed that the concentration of diisooctyl isophthalate was about 300 ppm, that is, the hydrogenation rate of benzene rings reached 99.97%.

Example 7

Add 1,2,4-benzenetricarboxylic acid and butanol with a molar ratio of 1:3.5 into the stirred tank reactor. The reactor uses an alcohol-water reflux layering device, and then adds an acid catalyst and heats to 230°C for esterification reaction , react until the acid value is lower than 0.2mgKOH/g. Take 3.3g of Y catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 50bar, the temperature is 250°C, the hydrogen flow rate is 100mL/min, the flow rate of the crude product of the esterification reaction is 4.5mL/h, hydrogen and 1,2,4-benzenetricarboxylic acid The molar ratio of tributyl ester is about 28:1. After the reaction, add alkali to neutralize acid, distill alcohol and by-products, filter and deash to obtain 1,2,4-cyclohexanetricarboxylate tributyl.

The concentration of residual benzene rings in the product was analyzed by ultraviolet-visible light spectrometer, and the analysis results showed that the concentration of tributyl 1,2,4-benzenetricarboxylate was about 0 ppm, that is, the hydrogenation rate of benzene rings reached 100%.

Example 8

Add 1,3,5-benzenetricarboxylic acid and isodecyl alcohol with a molar ratio of 1:3.3 into the stirred tank reactor. The reactor uses an alcohol-water reflux layering device, and then adds an acid catalyst and heats it to 210°C for esterification React until the acid value is lower than 0.2mgKOH/g. Take 3.3g of Y catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 70bar, the temperature is 180°C, the hydrogen flow rate is 100mL/min, the crude product flow rate of the esterification reaction is 4.5mL/h, hydrogen and 1,3,5-benzenetricarboxylic acid The molar ratio of triisodecyl ester is about 28:1. After the reaction, add alkali to neutralize and remove acid, distill to remove alcohol and by-products, filter and deash to obtain 1,3,5-cyclohexanetricarboxylate triisodecyl.

The concentration of residual benzene rings in the product was analyzed by ultraviolet-visible light spectrometer, and the analysis results showed that the concentration of triisodecyl 1,3,5-benzenetricarboxylate was about 700ppm, that is, the hydrogenation rate of benzene rings reached 99.93%.

Example 9

Add 1,2,3-benzenetricarboxylic acid and butanol with a molar ratio of 1:3.4 into the stirred tank reactor. The reactor uses an alcohol-water reflux layering device, and then adds an acid catalyst and heats it to 220°C for esterification reaction , react until the acid value is lower than 0.2mgKOH/g. Take 3.3g of Y catalyst and fill it in a stainless steel continuous trickle bed reactor with a diameter of 3/8 inches as a fixed bed (filling 6mL), and then directly feed the crude product of the esterification reaction without purification To the trickle bed reactor for hydrogenation reaction, the hydrogen pressure is 100bar, the temperature is 180°C, the hydrogen flow rate is 100mL/min, the flow rate of the crude product of the esterification reaction is 4.5mL/h, hydrogen and 1,2,3-benzenetricarboxylic acid tricarboxylate The molar ratio of butyl ester is about 28:1. After the reaction, add alkali to neutralize acid, distill alcohol and by-products, filter and deash to obtain 1,2,3-cyclohexanetricarboxylate tributyl.

The concentration of residual benzene rings in the product was analyzed by ultraviolet-visible light spectrometer, and the analysis results showed that the concentration of tributyl 1,2,3-benzenetricarboxylate was about 400ppm, that is, the hydrogenation rate of benzene rings reached 99.96%.

Example 10

Take 66.5g of X catalyst, fill it in a stainless steel continuous trickle bed reactor with a diameter of 1 inch as a fixed bed (filling 104mL), and then use the obtained 1,2-cyclohexanedicarboxylate diisononyl Carry out the second hydrogenation reaction, the hydrogen pressure is 70bar, the temperature is 85°C, the hydrogen flow rate is 418mL/min, the flow rate of diisononyl 1,2-cyclohexanedicarboxylate is 62.4mL/h, hydrogen and phthalic acid The molar ratio of diisononyl ester is about 28:1. The analysis results showed that the concentration of diisononyl phthalate was 100ppm, that is, the hydrogenation rate of benzene ring reached 99.99%.

The reaction condition and detection result of embodiment 1～10 are summarized, as shown in table 1:

The reaction condition and detection result of table 1 embodiment 1～10

Example catalyst Hydrogen pressure (bar) Hydrogenation temperature (°C) Phthalate Concentration (ppm) Hydrogenation rate of benzene ring (100%) 1 X catalyst 50 70 1000 99.90 2 X catalyst 50 100 500 99.95 3 X catalyst 50 120 400 99.96 4 X catalyst 100 70 400 99.96 5 Y catalyst 50 180 1000 99.90 6 Y catalyst 50 210 300 99.97 7 Y catalyst 50 250 0 100 8 Y catalyst 70 180 700 99.93 9 Y catalyst 100 180 400 99.96 10 X catalyst 70 85 100 99.99

From the results of Examples 1 to 9, it can be known that in the synthetic method of the present invention, the hydrogenation rate of the benzene ring of the crude phthalic acid esters is more than 99.9% (99.9 to 100%), which can fully meet the current regulations. Requirements (phthalates need to be below 1000ppm), PVC children's toys and related plastic products made of cyclohexane polybasic esters comply with the European Union's 1995/815/EC environmental resolution; and the results of Example 10 can be obtained It is known that after the second hydrogenation reaction, the concentration of diisononyl phthalate can be reduced to about 100 ppm, that is, the hydrogenation rate of the benzene ring of the crude product of diisononyl phthalate can be increased to 99.99%.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any changes or substitutions that can be easily imagined by those skilled in the art within the technical scope disclosed in the present invention, All should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. a method for synthesizing cyclohexane polybasic acid ester, it is characterized in that, after benzene polycarboxylic acid or its acid anhydride and alcohol esterification without aftertreatment, the crude product containing alcohol is directly catalytic hydrogenated to obtain cyclohexane polybasic acid ester esters. 2. the method for synthetic cyclohexane polybasic acid ester according to claim 1, is characterized in that, described benzene polycarboxylic acid is phthalic acid, isophthalic acid, terephthalic acid, 1,2,4 - benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid or 1,2,3-benzenetricarboxylic acid. 3. the method for synthesizing cyclohexane polybasic acid ester according to claim 1, is characterized in that, the step of described esterification is: be benzene polycarboxylic acid or its anhydride and alcohol with molar ratio 1:2.2～3.5 Put it into a stirred tank reactor, and the reactor uses an alcohol-water reflux stratification device, then adds an acid catalyst and heats it to 200~240°C, and reacts until the acid value is lower than 0.2mgKOH/g. 4. the method for synthetic cyclohexane polybasic acid ester according to claim 1, is characterized in that, described alcohol is C1～C30 alkyl alcohol, C3～C30 cycloalkyl alcohol and C1～C30 alkoxyalkyl at least one of alcohols. 5. the method for synthesizing cyclohexane polybasic acid ester according to claim 4 is characterized in that, described alcohol is at least one in butanol, isooctyl alcohol, isononyl alcohol and isodecyl alcohol. 6. the method for synthetic cyclohexane polybasic acid ester according to claim 1, is characterized in that, the step of described catalytic hydrogenation is: the crude product of esterification is directly fed into trickle bed reactor and carries out hydrogenation reaction, The hydrogen pressure is 40~100bar, the temperature is 70~250℃, and the catalyst is a porous oxide loaded with Group ⅧB metals. 7. The method for synthesizing cyclohexane polybasic acid ester according to claim 6, characterized in that, the Group VIIIB metal is at least one of ruthenium, rhodium and palladium. 8. the method for synthesizing cyclohexane polybasic acid ester according to claim 6, is characterized in that, described porous oxide is aluminum oxide-magnesia composite oxide. 9. the method for synthetic cyclohexane polybasic acid ester according to claim 1, is characterized in that, after catalytic hydrogenation, carry out aftertreatment: add alkali and remove acid, distillation or evaporation remove alcohol and remove by-product, filter and remove Ash. 10. the method for synthesizing cyclohexane polybasic acid ester according to claim 1, is characterized in that, be 1:2.2～3.5 benzene polycarboxylic acid or its anhydride and alcohol add in the stirred tank reactor with mol ratio, react The device uses an alcohol-water reflux stratification device, then adds an acid catalyst and heats to 200~240°C, reacts until the acid value is lower than 0.2mgKOH/g, and then directly feeds the crude product of the esterification reaction containing alcohol to the trickle bed reaction The hydrogenation reaction is carried out in a hydrogenation device, the hydrogen pressure is 40~100bar, and the temperature is 70~250℃. The catalyst is a porous oxide loaded with Group ⅧB metals. After the reaction, add alkali to neutralize and remove acid, distill or evaporate to remove alcohol and remove by-products , Filtration and deashing to obtain cyclohexane polybasic acid ester.