RU2754913C1 - Method for selective preparation of exo,exo- and endo,endo-di(2-ethylhexyl)norbornene-2,3-dicarboxylates from c5 fraction of liquid pyrolysis products - Google Patents

Abstract

FIELD: chemical industry.SUBSTANCE: invention relates to a method for the selective production of endo,endo-di(2-ethylhexyl)norbornene-2,3-dicarboxylate or a mixture of exo,exo- and endo,endo-di(2-ethylhexyl)norbornene-2,3-dicarboxylates, where the target compounds are obtained using a by-product of the production process: C5 fraction of liquid pyrolysis products, at the same time, at the first stage, endo-endic anhydride (EA) is obtained by a selective reaction of maleic anhydride (MA) with cyclopentadiene (CPD) contained in the C5 fraction of the LPP, for which finely ground MA is added in portions to the C5 fraction in a molar ratio of CPD:MA=1.00-1.10:1 when cooled so that the temperature of the reaction mass does not exceed 40°C, it is kept under stirring and at a temperature no higher than 40°C until the maleic anhydride is completely consumed, the reaction mass is diluted with 2-ethylhexanol (2-EH) in an amount of 60-65, wt. %, from the calculated one, the unreacted part of the C5 fraction is distilled at a temperature of 30-50°C, the remaining part of 2-EH is added to the reaction mass cubed and at the second stage, EA is esterified with 2-ethylhexanol either at a temperature of 120-157°C in toluene medium in the presence of an acid catalyst for the synthesis of endo,endo-di(2-ethylhexyl)norbornene-2,3-dicarboxylate, or at a temperature of 155-220°C without a solvent in the presence of an amphoteric catalyst for the synthesis of a mixture of endo,endo- and exo, exo-di(2-ethylhexyl)norbornene-2,3-dicarboxylates. The esters obtained can be used as monomers in the reaction of metathesis polymerization with the opening of the cycle, and also as an oil-phosphate plasticizer of PVC.EFFECT: processable and simple method for the selective production of endo, endo - and exo, exo-di(2-ethylhexyl)norbornene-2,3-dicarboxylates based on available raw materials: C5 fractions of liquid pyrolysis products and maleic anhydride.3 cl, 2 ex

Description

The invention relates to a method for the selective production of exo, exo and endo, endo-dialkyl norbornene-2,3-dicarboxylates from the C5 fraction of liquid pyrolysis products. The resulting esters can be used as monomers in ring opening methatesis polimerisation (ROMP) for the production of polymers with functional groups, and also as a non-phthalate PVC plasticizer.

The main method for preparing diesters of norbornenes is the reaction of [4 + 2] cycloaddition (Diels-Alder reaction) of cyclopentadiene (CPD) with maleic anhydride, followed by esterification of the resulting endic anhydride with a monohydric alcohol (Scheme 1).

Scheme 1

CPD is a very unstable compound under normal conditions; it readily dimerizes in DCPD; therefore, it is isolated immediately before the process from DCPD by heating at 163-172 ° C in the presence of thermopolymerization inhibitors (Scheme 2).

Scheme 2

For metathesis polymerization, an important factor is the spatial arrangement of ether substituents relative to the norbornene bicycle, which can have exo, exo, endo, endo or exo, endo orientation (Scheme 3). The speed of the polymerization process, the value of the activation energy, and the properties of the obtained polymer depend on this.

In all known methods, esters of norbornene-dicarboxylic acid are predominantly obtained on the basis of pure compounds using solvents and catalysts, which significantly increases the cost of the process and limits the industrial applicability of the method. DCPD is isolated from ZHP fractions, and its isolation and purification is a rather laborious and energy-consuming process.

A known method of producing di (2-ethylhexyl) norbornene-2,3-dicarboxylates by the Diels-Alder reaction of di (2-ethylhexyl) maleates and di (2-ethylhexyl) fumarates with cyclopentadiene (CPD) in a solvent in the presence of a titanium chloride catalyst (Park JS ., Oh H-Ch., Park YS., WooJ-W. // Adv. Mater. Reserch, 2012, V. 421, P. 136). A known method for producing dialkylnorbornene-2,3-dicarboxylates by the Diels-Alder reaction of maleic anhydride with CPD followed by esterification of norbornene anhydride with monohydric alcohols C ₄ -C ₁₃ , or by the reaction of maleic acid diesters with CPD (US patent 2013171385, 2013).

The disadvantages of the known methods are the use of pure CPP, the need to use a solvent and catalyst, which increases the cost of the process, complicates the purification of the final product, and limits the industrial applicability of the method. The cost of dialkylnorbornene-2,3-dicarboxylates can be significantly reduced by using by-products of petrochemical production as raw materials.

It is known to use, as a source of CPD C5, a fraction of liquid pyrolysis products (ZPP), a large-tonnage by-product of the pyrolysis production of ethylene and propylene. The fraction is a mixture of low-boiling C ₅ hydrocarbons with an admixture of C ₄ and C ₆ hydrocarbons, boils within the range of 30-70 ° C and contains alkanes, olefins and dienes, while the content of 1,3-dienes (isoprene, piperylene and CPD), which can participate in the Diels-Alder reaction, can reach 40-50%. The content of CPD in the C5 fraction ranges from 5 to 20-25%, depending on the composition of the feedstock and pyrolysis conditions.

There is a known method in which the C5 fraction is heated with maleic anhydride (MA) at 70-180 ° C in an autoclave for 8 hours, a mixture of anhydrides is obtained, unreacted hydrocarbons are removed by distillation, and then the mixture of anhydrides is esterified with 2-ethylhexanol or isonanol. The resulting mixture of esters is used as a PVC plasticizer (US patent 7319161, 2008). In this method, MA reacts with all 1,3-dienes - isoprene, piperylene, and CPD to form, respectively, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid anhydrides, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid and 5-norbornene-2,3-dicarboxylic acid.

A method of obtaining similar mixtures of anhydrides by reaction with AI C5 fraction at a reaction temperature 30-35 ° C and a molar ratio of 1,3-dienes: AI equal to 0.9-1.5: 1. Further, the unreacted portion C ₅ fraction is distilled off and carried out the esterification of the mixed anhydride 2 - ethylhexanol fraction isolated from the distillation residue of rectification of butyl alcohols (KORBS), obtaining a mixture of the corresponding esters that can be used as a PVC plasticizer (patent RU 2691739, 2018).

The disadvantages of these methods are the non-selectivity of the process and the production of a mixture of compounds, which can limit the scope of their practical application.

The closest in technical essence is a method for the selective production of diesters of norbornene-2,3-dicarboxylic acid by the interaction of CPD contained in the C5 fraction with previously obtained diesters of fumaric acid (patent RU 2625788, 2016). The reaction is carried out at a reaction mass temperature of 16-20 ° C and a molar ratio of the alkyl diester of fumaric acid and CPE equal to 1: 1.5-3.0, dosing the C5 fraction into the alkyl diester of fumaric acid, continue the reaction at room temperature until the complete consumption of the fumaric acid ester and excess fraction With _{5 is} distilled off at a temperature of 30-60 ° C. The disadvantage of the proposed method is the use of scarce fumaric acid as a raw material. In addition, only exo, endo-dialkyl norbornene-2,3-dicarboxylates can be obtained by this method.

The aim of the invention is a technological and simple method for the selective production of endo, endo- and exo, exo-di (2-ethylhexyl) norbornene-2,3-dicarboxylates based on available raw materials - C5 fraction of liquid pyrolysis products and maleic anhydride.

The technical result is achieved by the fact that, at the first stage, endo-endic anhydride (EA) is selectively obtained by the reaction of maleic anhydride (MA) with cyclopentadiene contained in the C5 fraction of the LPP, for which finely ground MA is added in portions to the C5 fraction in the molar ratio of CPA: MA = 1.00-1.10: 1 on cooling so that the temperature of the reaction mixture does not exceed 40 ° C, is kept with stirring and at a temperature not higher than 40 ° C until maleic anhydride is completely consumed, the reaction mass is diluted with 2-ethylhexanol (2-EG) in an amount of 60-65% of the calculated one, the unreacted part of the C5 fraction is distilled off at a temperature of 30-50 ° C, the remaining 2-EG is added and then, in the second stage, EA is esterified with 2-ethylhexanol or at a temperature of 120-157 ° C in a toluene medium in in the presence of an acidic catalyst for the synthesis of endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate, or at a temperature of 155-220 ° C without solvent in the presence of an amphoteric catalyst for the synthesis of a mixture of endo, endo- and exo, exo-di (2-ethylhexyl) norbornene-2,3-dicarboxylates. For the synthesis of endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate, the molar ratio of reagents EA: 2-EG = 1: 2.4-2.7, the mass ratio of 2-EG: toluene = 1: 0 , 8-1 and acid catalyst para-toluenesulfonic acid (PTSA) in the amount of 0.9-1.2% wt. from the estimated amount of EA. To obtain a mixture of endo, endo- and exo, exo-di (2-ethylhexyl) norbornene-2,3-dicarboxylates, the molar ratio EA: 2-EG = 1: 2.9-3.3 and the catalyst tetrabutoxytitanium in an amount of 0, 9-1.2% wt. from the estimated amount of EA.

At the end of the esterification process, the excess of 2-EG and the solvent is distilled off under reduced pressure, the product obtained in the still is neutralized and purified by known methods.

The content of CPP in the C5 fraction is determined by the GLC method and the amount of the C5 fraction is calculated to provide the required molar ratio of MA and CPD. The use of the C5 fraction as a source of CPD in the claimed method allows the reaction to be carried out without a solvent, since the role of the solvent is played by the remaining components of the C5 fraction. The use of a dilute CPD solution eliminates a sharp rise in temperature during the addition of MA to the C5 fraction and simplifies the process.

The esterification catalyst is taken in an amount of 0.9 ÷ 1.2% wt. from the estimated mass of EA. A decrease in this amount leads to an incomplete course of the esterification reaction and a significant increase in the reaction time, an increase leads to an unreasonable consumption of the catalyst.

The invention is illustrated by specific examples.

Example 1. Obtaining endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate

A flask was charged with 444.0 g of a cooled C5 fraction with a CPD content of 16.38% (72.71 g or 1.1 mol). With stirring and cooling, 98.06 g (1.0 mol) of maleic anhydride (MA) was added in 3 portions. With the addition of MA, an exothermic effect was observed with the heating of the reaction mixture to 30 ° C and the precipitation of flakes of crystalline endic anhydride. After adding the last portion of MA, the mixture was additionally heated at a temperature of the mixture not higher than 40 ° C for 1 h. During this time, maleic anhydride was completely consumed. The resulting endo-endic anhydride (164.20 g, 1 mol) was not isolated, but was added after cooling to a heterogeneous mixture of 208.32 g (1.6 mol) of 2-ethylhexanol. The unreacted part of the C5 fraction was distilled off at T _steam = 30-51 ° C (352.60 g). A transparent homogeneous solution of slightly yellowish color was obtained in the cube. After cooling, 330 g of toluene, 130.20 g (1.0 mol) of 2-ethylhexanol (total amount of loaded 2-ethylhexanol 338.52 g or 2.6 mol), 0.5 g (0.3% from the mass of endic anhydride) catalyst of para-toluenesulfonic acid (PTSA). Equipped the flask with a thermometer and a Dean-Stark head with a reflux condenser. The esterification reaction was carried out at a temperature of 120-137 ° C for 6.5 hours with the simultaneous distillation of the reaction water by azeotrope with toluene. During this time, about 10 g of water was released as an azeotrope (out of the calculated 18 g of water). After slowing down the rate of water evolution in the Dean-Stark nozzle, another 1.0 g of PTSA g (0.6% by weight of endic anhydride) was added to the reaction mixture and the reaction was carried out at a temperature of 130-150 ° C for 10.5 hours. time, about 8 g of water was released, a total of 18 g. The acid number of the reaction mixture was 6.5 mg KOH / g, weight 577.83 g. Toluene and an excess of 2-ethylhexanol were distilled off at 10-12 mm Hg. and T _steam = 30-90 ° C. Distillation - a transparent almost colorless liquid, 153.44 g Obtained in a still 399.15 g of a brown liquid. For neutralization, 3.60 g of NaHCO ₃ and 4.20 g of distilled water were added to the cube, heated with stirring, and filtered hot. Received 328.0 g of a clear yellow liquid with a content of the target product of 97.8% according to GLC. By ¹ H NMR spectra and ¹³ C, the product consists of one isomer - endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate.

¹³ C spectrum (CDCl ₃ , δ ppm): 10.92 (C25); 10.92 (C16); 14.00 (C23); 14.00 (C14); 22.97 (C13); 22.97 (C22); 23.77 (C15); 23.77 (C24); 28.91 (C12); 28.91 (C21); 30.41 (C20); 30.41 (C11); 38.64 (C10); 38.64 (C19); 46.38 (C1); 46.38 (C4); 48.11 (C3); 48.11 (C2); 48.68 (C7); 66.82 (C18); 66.82 (C9); 134.83 (C6); 134.83 (C5); 172.53 (C17); 172.53 (C8).

Spectrum¹H (CDCl₃, δ ppm,J Hz): 0.88 (t, 3H,³ J _16-15= 7.5, H-25); 0.88 (t, 3H,³ J _16-15= 7.5, H-16); 0.90 (t, 3H,³ J _14-13= 6.6, H-23); 0.90 (t, 3H,³ J _14-13= 6.6, H-14); 1.28 (m, 2H, H-11); 1.28 (m, 2H, H-12); 1.28 (m, 2H, H-20); 1.28 (m, 2H, H-21); 1.29 (m, 2H, H-13); 1.29 (m, 2H, H-22); 1.33 (m, 1H, Hb-7); 1.34 (m, 2H, H-24); 1.34 (m, 2H, H-15); 1.47 (dt, 1H,² J= 8.6,³ J _{7a-4 (1)} = 1.9,⁴ J _{7a-5 (6)} = 1.9, Ha-7); 1.54 (m, 1H, H-19); 1.54 (m, 1H, H-10); 3.16 (n, 1H,³ J _1-2 = 1.9³ J _1-6 = 1.9,³ J _1-7a = 1.9,³ J _1-7b = 1.9, H-1); 3.16 (n, 1H,³ J _4-3 = 1.9³ J _4-5 = 1.9,³ J _4-7a = 1.9,³ J _4-7b = 1.9, H-4); 3.28 (t, 1H,³ J _2-1 = 1.9,⁴ J _2-7b = 1.9, H-2); 3.28 (t, 1H,³ J _3-4 = 1.9,⁴ J _3-7b = 1.9, H-3); 3.83 (m, 1H, H-9b); 3.83 (m, 1H, H-18b); 3.99 (m, 1H, H-18a); 3.99 (m, 1H, H-9a); 6.24 (t, 1H,³ J _5-4 = 1.9,⁴ J _5-7a = 1.9, H-5); 6.24 (t, 1H,³ J _6-1 = 1.9,³ J _6-7a= 1.9, H-6).

Example 2. Preparation of a mixture of exo, exo and endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate

Endicic anhydride (164.2 g, 1 mol) was obtained according to example 1 from 444.0 g of cooled C5 fraction with a CPA content of 16.38% (72.71 g or 1.1 mol) and 98.06 g (1.0 mol) of crushed maleic anhydride, was added after cooling to a heterogeneous mixture of 247.38 g (1.9 mol) of 2-ethylhexanol. The unreacted part of the C5 fraction was distilled off at T _steam = 30-50 ° C (352.70 g). A transparent homogeneous solution of slightly yellowish color was obtained in the cube. An additional 156.24 g (1.2 mol) of 2-ethylhexanol (total 403.62 g of 2-ethylhexanol, 3.1 mol) and 0.5 g of tetrabutoxytitanium catalyst (TBT) were added to the reaction mass. Equipped the flask with a thermometer and a Dean-Stark head with a reflux condenser. The esterification reaction was carried out at a temperature of 155-188 ° C with simultaneous distillation of the azeotrope. Within 4 hours, about 11 g of water was released as an azeotrope (out of the calculated 18 g), then the release of water slowed down. Another 1.00 g of TBT was added to the reaction mixture and the reaction was continued at a temperature of 169-210 ° C for 8 hours. During this time, another 7 g of water was evolved. A clear, bright yellow solution with an acid number of 0.5 mg KOH / g was obtained. The excess of 2-ethylhexanol was distilled off at a pressure of 10-12 mm Hg. Art. and T _steam = 55-85 ° C. Distillation - a clear, colorless liquid, 196.55 g. 413.43 g of a dark yellow transparent liquid with an acid number of 0.5 mg KOH / g were obtained in a cube. For neutralization, 3.5 g of a 20% NaHCO ₃ solution was added to the cube, heated with stirring, filtered hot. Received 330.0 g of a transparent bright yellow liquid with a content of the target product of 98% according to GLC.

By ¹ H NMR spectra and ¹³ C, the product consists of a mixture of isomers - exo, exo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate (60%) and endo, endo-di (2-ethylhexyl) 2-norbornene, 3-dicarboxylate (40%).

Exo, exo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate (60%)

¹³ C spectrum (CDCl ₃ , δ ppm): 10.56 (C25); 10.56 (C16); 13.64 (C23); 13.64 (C14); 22.61 (C13); 22.61 (C22); 23.43 (C15); 23.43 (C24); 28.54 (C12); 28.54 (C21); 30.07 (C20); 30.07 (C11); 38.35 (C10); 38.35 (C19); 44.99 (C7); 45.35 (C1); 45.35 (C4); 46.96 (C2); 46.96 (C3); 66.29 (C18); 66.29 (C9); 137.54 (C6); 137.54 (C5); 173.06 (C17); 173.06 (C8).

Spectrum¹H (CDCl₃, δ ppm,J Hz): 0.77 (q, 3H,³ J _16-15= 7.3, H-16); 0.77 (q, 3H,³ J _25-24= 7.3, H-25); 0.77 (q, 3H,³ J _23-22= 7.3, H-23); 0.77 (q, 3H,³ J _14-13= 7.3, H-14); 1.18 (m, 2H, H-11); 1.18 (m, 2H, H-12); 1.18 (m, 2H, H-13); 1.18 (m, 2H, H-20); 1.18 (m, 2H, H-21); 1.18 (m, 2H, H-22); 1.23 (m, 2H, H-15); 1.23 (m, 2H, H-24); 1.35 (d, 1H,² J= 8.8, Ha-7); 1.44 (m, 1H, H-10); 1.44 (m, 1H, H-19); 2.03 (d, 1H,² J= 8.8, Hb-7); 2.49 (m, 1H, H-2); 2.49 (m, 1H, H-3); 2.95 (m, 1H, H-1); 2.95 (m, 1H, H-4); 3.89 (m, 2H, H-18); 3.89 (m, 2H, H-9); 6.09 (dd, 1H,³ J _5-4 = 2.3,⁴ J _5-1 = 1.7, H-5); 6.09 (dd, 1H,³ J _6-1 = 2.3,³ J _6-4 = 1.7, H-6).

Endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate (40%)

¹³ C spectrum (CDCl ₃ , δ ppm): 10.56 (C25); 10.56 (C16); 13.64 (C23); 13.64 (C14); 22.61 (C13); 22.61 (C22); 23.43 (C15); 23.43 (C24); 28.54 (C12); 28.54 (C21); 30.07 (C20); 30.07 (C11); 38.35 (C10); 38.35 (C19); 46.04 (C1); 46.04 (C4); 47.68 (C3); 47.68 (C2); 48.26 (C7); 66.66 (C18); 66.66 (C9); 134.41 (C6); 134.41 (C5); 172.00 (C17); 172.00 (C8).

Spectrum¹H (CDCl₃, δ ppm,J Hz): 0.77 (q, 3H,³ J _16-15= 7.3, H-16); 0.77 (q, 3H,³ J _25-24= 7.3, H-25); 0.77 (q, 3H,³ J _23-22= 7.3, H-23); 0.77 (q, 3H,³ J _14-13= 7.3, H-14); 1.18 (m, 2H, H-11); 1.18 (m, 2H, H-12); 1.18 (m, 2H, H-13); 1.18 (m, 2H, H-20); 1.18 (m, 2H, H-21); 1.18 (m, 2H, H-22); 1.22 (d, 1H,² J= 6.7, Hb-7); 1.23 (m, 2H, H-15); 1.23 (m, 2H, H-24); 1.34 (d, 1H,² J= 6.7, Ha-7); 1.44 (m, 1H, H-10); 1.44 (m, 1H, H-19); 3.02 (m, 1H, H-1); 3.02 (m, 1H, H-4); 3.16 (m, 1H, H-3); 3.16 (m, 1H, H-2); 3.73 (m, 2H, H-18); 3.73 (m, 2H, H-9); 6.11 (dd, 1H,³ J _5-4 = 3.0,⁴ J _5-1 = 1.8, H-5); 6.11 (dd, 1H,³ J _6-1 = 3.0,³ J _6-4 = 1.8, H-6).

Claims (3)

1. A method for the selective production of endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate or a mixture of exo, exo- and endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylates, characterized in that that the target compounds are obtained using a by-product of production - the C5 fraction of liquid pyrolysis products, while at the first stage endo-endic anhydride (EA) is obtained by the selective reaction of maleic anhydride (MA) with cyclopentadiene (CPA) contained in the C5 fraction of the liquid pyrolysis which finely crushed MA is added in portions to the C5 fraction in a molar ratio of CPD: MA = 1.00-1.10: 1 while cooling so that the temperature of the reaction mass does not exceed 40 ° C, is kept under stirring and at a temperature not higher than 40 ° C until complete consumption of maleic anhydride, dilute the reaction mass with 2-ethylhexanol (2-EG) in an amount of 60-65% wt. from the calculated one, the unreacted part of the C5 fraction is distilled off at a temperature of 30-50 ° C, the remaining part of 2-EG is added to the reaction mass in a still, and at the second stage EA is esterified with 2-ethylhexanol or at a temperature of 120-157 ° C in a toluene medium in the presence of acidic catalyst for the synthesis of endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate, or at a temperature of 155-220 ° C without solvent in the presence of an amphoteric catalyst for the synthesis of a mixture of endo, endo- and exo, exo-di ( 2-ethylhexyl) norbornene-2,3-dicarboxylates. 2. The method according to claim 1, characterized in that to obtain endo, endo-di (2-ethylhexyl) norbornene-2,3-dicarboxylate at the esterification stage, the molar ratio of reagents EA: 2-EG = 1: 2.5- 2.7, the mass ratio of 2-EG: toluene = 1: 0.8-1 and the acid catalyst para-toluenesulfonic acid (PTSA) in the amount of 0.9-1.2% wt. from the estimated amount of EA. 3. The method according to claim 1, characterized in that to obtain a mixture of endo, endo- and exo, exo-di (2-ethylhexyl) norbornene-2,3-dicarboxylates at the esterification stage, the molar ratio of EA: 2-EG = 1 : 2.9-3.3 and the catalyst tetrabutoxytitanium in the amount of 0.9-1.2% wt. from the estimated amount of EA.