CS218170B1 - Method of making the polysterpolyoles - Google Patents

Abstract

The invention solves the question of the production of polyester polyols from non-traditional starting raw materials when it uses the raw material residues from the production of difearboxylic acids from their esterification or distillation residues from such processes. They are particularly suitable for distillation residues from the production of dimethyl terephthalate. The procedure also compensates for the presence in the solution certain metals and their compounds that are usually present in these residues. The invention can be implemented in companies producing dicarboxylic acids and their esters, will occur in businesses performing transesterification.

Description

The invention relates to a process for the production of polyester polyols from technically readily available petrochemical raw materials and intermediates.

Polyester polyols are generally prepared by reacting dicarboxylic or polycarboxylic acids or their anhydrides with divalent or polyhydric alcohols, the amount of which depends on the kind of raw materials used and the desired properties of the resulting product. Dicarboxylic or polycarboxylic acids which may be used are: oxalic, malonic, succinic, glutaric, adipic, pimelic, cork, azelaic, sebacic, malicic, fumaric, glutaconic, alpha-hydroxymuconic, alpha-butyl-alpha-ethylglutaric, alpha-beta diethylsuccinic, isophthalic, terephthalic, pyramelite, trimezinic and 1,4-cyclohexanedicarboxylic. In technical practice, high purity adipic acid [Trans. Plastic. Inst., London 26, 187 (1958); Mod. Plastic. 35, 9, 145, 1958; Ing. Eng. Chem. 2, 27, 1963; B.I.O.S. Final Report No 1498; Dombrov E.A., Polyurethane SNTL, Prague 1961, p. 32], In spite of the evident advantages of such pure starting dicarboxylic or polycarboxylic acids, the disadvantage is not only for a number of applications the high technical and energy demands of their production, but also the limited resources of pure raw materials for their production and the need for technically demanding equipment. This limits the possibilities of applying polyester polyols to the production of mass products.

Among the alcohols, polyhydric aliphatic and aromatic alcohols are suitable, in particular ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, tetraethylene glycol, trimethylene glycol, 1,4-tetramethylene glycol, 1,2-butylenediol, 1,3-butylene glycol. , 1,6-hexanediol, 1,7-heptanediol, glycerol, 1,1,1-trimethylolpropane, 1,1,1-trimethylolethane opentyl glycol, 1,2,6-hexanetriol, dibromoneopentyl glycol, 1,10-decanediol, pentaerythritol, 2 , 2-bis-4-hydroxycyclohexyl propane and others (BIOS Final Report No 1498, No 1166; British Pat. 882 603; British Pat. 927 175).

Synthesis, resp. The production of polyester polyols is usually carried out at temperatures of 130 to 240 ° C at atmospheric or near atmospheric pressure, generally in the presence of catalysts and with removal of the reaction water by an inert gas or azeotropic distillation with xylene. Another possible method for preparing polyester polyols by re-esterification of dicarboxylic acid esters is not practiced in practice because it requires an additional step to prepare dicarboxylic acid esters, which is technically and economically more demanding. Such a procedure is usually used only in the preparation of polyesters by re-esterification of natural oils, e.g. soybean oil with polyhydric alcohols in the production of alkyd resins for the medical industry or in the production of polyethylene terephthalate. The transesterification is carried out at temperatures of 180 to 240 ° C in the presence of

0.005 to 0.1 wt. Catalyst (Mleziva J .: Polyesters, SNTL Praha 1964).

According to the invention, a process for the production of polyester polyols by transesterification and / or polyesterification of the acid component with diols or polyols at a pressure of from 1 kPa to 3.8 MPa and a temperature of 120 to 300 ° C, usually in the presence of esterification catalyst, usually under atmospheric, preferably in inert gas stream. and / or the quencher of the low-molecular-weight products of the reaction is carried out by using, for transesterification and / or polyestenification, an acid component in part or a complete distillation residue from the production of terephthalic acid and / or dimethyl terephthalate.

An advantage of the process for the production of polyester polyols according to the present invention is the technical and economic evaluation of the distillation residue from both the production of terephthalic acid and the production of dimethyl terephthalate as by-products, thereby expanding the raw material base for the production of polyester polyols. Another advantage is that the application of the process according to the invention in connection with the production of dimethyl terephthalate or terephthalic acid makes their processes virtually waste-free.

In the production of polyester polyols, either the distillation residue itself from the production of dimethyl terephthalate and / or terephthalic acid, and / or together with known, mainly aliphatic dicarboxylic acids and optionally polycarboxylic acids, or their anhydrides and / or lactones, can be used in the amounts required to achieve the desired properties. product. The metals and their compounds present in the distillation residue or in the esterification residue such as cobalt, chromium, manganese, iron, or trace amounts of calcium, magnesium, barium, silicon and media or others of the preceding process act as catalysts for transesterification and polyesterification. In the proposed process, transesterification of acid esters and esterification of the acids present in the starting material and / or additionally added to the polyesterpolyol-forming reaction medium take place side by side.

From the above, it is clear that the proposed process for producing polyester polyols can be accelerated by known transesterification catalysts, respectively. esterification as well as polyesterification in amounts so as to achieve a technically and economically suitable rate of the reactants without undesirable side, mainly degradation reactions. For some purposes, the distillation residue and / or esterification residues from the production of dimethyl terephthalate, respectively. terephthalic acid, e.g. decolorize with conventional cleaning operations, remove metals by the addition of acids, ion exchangers and / or distillation, steaming, and the like.

From the distillation residue from the production of dimethyl terephthalate and / or terephthalic acid, substantially all kinds of polyester polyols close to the end properties known to the polyester polyol can be prepared. Aliphatic and aromatic polyhydric alcohols, in particular ethylene glycol, diethylene glycol, triethylene glycol, 1,2-dipropylene glycol, trimethylene glycol, 1,4-tetramethylene glycol, 1,2-butylene glycol, 1,4-butanediol, 1,4-butanediol can be used for the process of the present invention. , 1,3-pentanediol, 1,6-hexanediol, 1,7-heptanediol, divalent and polyvalent polyglycols, glycerol, 1,1,1-trimethylolpropam, 1,1,1-tramethyl ethyloline, non-pentyl glycol, 1,2,6-hexanetriol, dibromonopentyl glycol, 1,10-decanediol, pentaerythritol, dipentaerythritol, 2,2'-bis- (4-hydroxycyclohexyl) propane, amino alcohols and thioalcohols, or other compounds capable of reacting with diesters and carboxylic acids.

The preparation of polyester polyols from dimethyl terephthalate residues can be carried out in the presence of cobalt, chromium, manganese, iron, mainly in the form of their oil-soluble compounds and other trace compounds present in the residue from esterification of dimethyl terephthalate and / or presence of known polyesterification catalysts in known types of equipment at temperatures of 120 to 280 ° C (Brit. Pat. 1,278,953; Brit. Pat. 1,279,716; Brit. Pat. 1,282,482; Brit. Pat. 1,351,851; Brit. U.S. Patent 1,363,446; British Patent 1,305,130; U.S. Patent 3,819,585; U.S. Patent 3,822,239). Removal of the secondary product of transesterification and / or polyesterification, i. j. methanol and water can be accelerated by purging the reaction mixture with an inert gas and / or a suitable hydrocarbon, e.g. xylene, cumene, diethylbenzene and the like. These have the function of entrainer, which in the form of vapors together with the vapors of the low molecular weight transesterification and polyesterification products, such as methanol, water and the degradation product, are carried away from the reaction medium. In the course of the reaction, conditions such that solid compounds such as dimethyl terephthalate, which are then deposited in the condenser and cause operational difficulties, should be avoided at the same time as methanol.

The polyester polyols according to the invention are usually prepared without the use of a solvent in the final form. It will be understood that hydrocarbons may also be used in the polyesterification process to remove by-products from the reaction medium and, upon completion of the reaction, a portion of the solvent will remain in the reaction product for further application.

The process according to the invention can be carried out in particular discontinuously, but can also be carried out semi-continuously and continuously.

Further details of the method, as well as other advantages, are apparent from the exemplary embodiments. Example 1

Polyester polyol is prepared in a four-necked flask with a volume of δ ° ^3, equipped with a stirrer, a temperature controller, a short non-tempered riser and a nitrogen inlet.

Weigh into the flask 1500 g of the distillation residue from dimethyl terephthalate production (saponification number - 472 mg KOH / g; acid value = 56,0 mg KOH / g; cobalt content in the form of salts = 0,45% w / w; deposit = 4.7 dimethyl terephthalate - 8.2% by weight trimethyl trimethyl ester = 3% by weight p-methyltoluylate = 0.2% by weight, the remainder being mainly condensation products of dicarboxylic and tricarboxylic acids and their methyl esters, average molecular weight weight = 320; melting point = 55 ° C), 1500 g of diethylene glycol, 250 g of pentaerythritol and 1.5 g of lead oxide as catalyst. Re-esterification is carried out at 200 ° C with stirring (stirrer speed 250 / min), using nitrogen in an amount of 40 dm ³ to distill methanol more efficiently. h ' ¹ . The re-esterification was completed in 5 h. A dark-colored polyester polyol having an acid number of 1 mg KOH / g, a hydroxyl number of 460 mg KOH / g, a viscosity of 4.2 Pa is obtained. s at 25 ° C.

Example 2

Weigh 1500 g of esterification residues, respectively, into a sulfonation flask. distillation residues from the production of dimethyl terephthalate (acidity = 48.7 mg KOH / g; saponification - 482.7 mg KOH / g; dimethyl terephthalate content - 10.8% by weight; trimethyl ester of trimellitic acid = 3.6% by weight; p-methyltoluylate = 0.1% by weight, Co content = 0.16% by weight in the form of soluble Co compounds, 0.05% by weight of Mn and Cr compounds; deposits = 0.3% by weight; condensation products of dicarboxylic and tricarboxylic acids and their esters; melting point = 41 ° C; average molecular weight = 301); 1500 g of diethylene glycol and 220 g of glycerol. Following the procedure of Example 1 in the absence of a catalyst, the reaction lasted 8 hours. The product is dark in color with an acid number of 0.6 mg KOH / g, a hydroxyl number of 450 mg KOH / g and a viscosity of 3.2 Pa. s at 25 ° C.

Example 3

The polyester polyol was prepared by the procedure of Example 1 by reacting 1500 g of esterification residues from the production of dimethyl terephthalate, 1200 g of diethylene glycol and 250 g of trimethylolpropane in the presence of 1.3 g of lead oxide as catalyst. The reaction time of the transesterification and polyesterification at 200 ° C is 6 h. A dark polyester polyol having an acid number of 0.5 mg KOH / g, a hydroxyl number of 280 mg KOH / g and a viscosity of 4.6 Pa is obtained. s at 25 ° C.

Example 4

Following the procedure of Example 1, the polyester polyol is prepared by reacting 1500 g of esterification residues from the production of dimethyl terephthalate,

550 g of monoethylene glycol without catalyst.

The reaction time of transesterification and polyester fiction is 13 h. The polyesterpolyol obtained had a melting point of 70 ° C, a hydroxyl number of 150 mg KOH / g and an acid number of 0.3 mg KOH / g. Example 5

Weigh 2000 g of the distillation residue from the production of dimethyl terephthalate, 1050 g of diethylene glycol and 1.5 g of antimonytriphenyl into a sulfoma flask. Following the procedure of Example 1, the transesterification time at 200 ° C is 10 h. A dark-colored polyester polyol is prepared having an acid number of 1.1 mg KOH / g, a hydroxyl number of 52 mg KOH / g and a melting point of 35 ° C.

Example 6

As described in Example 1, the polyester polyol was prepared by transesterification of 1500 g of the dimethyl terephthalate residue, 217 g of monoethylene glycol and 315 g of 1,4-butanediol at 190 ° C in the presence of 1.5 g of amorphous germanium dioxide for 9 h. The polyester polyol has an acid number of 0.6 mg KOH / g and a hydroxyl number of 56 mg KOH / g.

Example 7

Polyesterpolyol is prepared in a 5 dm ³ four-necked flask equipped with a stirrer, a transesterification attachment with a short heated riser, an electric heater, a temperature controller, and a nitrogen inlet. Weigh 1200 g of esterification residues from the production of dimethyl terephthalate (acidity = 48.7 mg KOH / g; saponification value = 482.7 mg KOH / g; dimethyl terephthalate content = 10.8% by weight; trimethyl trimellitate = 3.6% by weight, p-methyltoluylate = 0.1% by weight, Co content = 0.16% by weight in the form of soluble Co compounds, 0.05% by weight Mn and Cr compounds, deposits - 0.3% the remainder being the condensation products of dicarboxylic and tricarboxylic acids and their esters; melting point = 41 ° C; average molecular weight = 301); 143 g of adipic acid; 217 g of ethylene glycol; 315 g of 1,4-butanediol; 0.9 g; lead oxide and 0.5 g tetrabutyl titanate. Polyesterification and transesterification at a temperature of 230 ° C for 10 h while removing water and methanol as the products of polyesterification and transesterification with nitrogen yield a mixture

Claims (1)

The resulting polyester polyol had a melting point of 70 ° C, a hydroxyl value of 150mg KOH / g and an acid number of 0.3 mg KOH / g. Example 5 Weigh 2,000 g of desulfurizing residue from the production of dimethyl terephthalate, 1050, into a sulfinating flask. g of diethylene glycol and 1.5 g of antimonytriphenyl. According to the procedure of Example 1, the transesterification time at 200 ° C is 10 h. A polyester polyol of dark color with an acid number of 1.1 mg KOH / g, a hydroxyl number of 52 mg KOH / g and a temperature of 35 ° C is prepared. EXAMPLE 6 Following the procedure of Example 1, the polyester polyol was prepared by transesterification of 1500 g of residue from the production of dimethyl terephthalate, 217 g of mono-ethylene glycol and 315 g of 1,4-butanediol at 190 DEG C. in the presence of 1.5 g of amorphous germanium oxide. for 9 h. Polyester polyol has an acid number of 0.6 mg KOH / g and a hydroxyl number of 56 mg KOH / g. EXAMPLE 7 A polyesterpolyol is prepared in a 5 dm 3 quartz flask equipped with a stirrer, a short heating riser transesterifier, an electric heater, a temperature regulator and a nitrogen inlet. 1200 g of esterification residues from the production of dimethylterephthalate (acid value = 48.7 mg KOH / g; wash off = 482.7 mg KOH / g; dimethyl terephthalate content = 10.8) were weighed into a flask. trimethyl trimellitic acid = 3.6 wt%, p-methyl toluene = 0.1 wt%, Co = 0.16 wt% as soluble compounds, 0.05 wt% Mn and The remainder consists of condensation products of dicarboxylic and tricarboxylic acids and their esters, melting point = 41 ° C, average molecular weight = 301, 143 g of adipic acid, 217 g of ethylene glycol, 315 g of 1,4- butanediol, 0.9 g lead oxide and 0.5 g tetrabutyl titanate. Polyesterification and transesterification at 230 [deg.] C. for 10 hours to remove water and methanol as polyesterification products and transesterification with nitrogen to give a mixture of polyester polyols by transesterification and / or polyesterification of the acid component with diols or polyols under pressure1 a pressure in the presence of an esterification and / or re-esterification catalyst, customary atmospheres, preferably in a stream of inert gas-polyester polyols having a hydroxyl number of 54 mg KOH / g and an acid number of 0.8 mg KOH /. EXAMPLE 8 The polyester polyol is prepared as described in Example 7. Weigh 1350 g of esterification and, respectively, to the flask. distillation residues from the production of dimethyl terephthalate, 78 phthalic anhydride, 217 g of ethylene glycol, 315 g of 1,4-butanediol, 1.2 g of antimony octoate, 0.6 g of tert-butyl titanate. Both transesterification and polyesterification are carried out at 150 DEG-210 DEG C. for 9 hours with removal of methanol and carbon dioxide water and xylene present in the reaction mixture at 100 g. A dark polyester polyol with a hydroxyl number of 56 mg KOH is obtained. / g and an acid number of 0.6 mg KOH / g. EXAMPLE 9 Preparation of polyester polyol from residues from terephthalic acid production in a four-necked flask equipped with a stirrer, a heating device, a temperature regulator, a stopper and a water cooler and a conduit inlet. 1200 g of terephthalic acid production residue (acidity 520 mg KOH / g, saponification 10.5 mg KOH / g) and 723 g diethylene glycol, 100 g xylene, 0.2 g tetrabutyl titanate and 0.006 g triethylamine were weighed into the flask. The reaction is carried out at 200 ° C under azeotropic removal of water. Upon conversion of 90-95%, the progressive pressure of the polyesterification apparatus decreases to 8 kPa, which accelerates the removal of both the water and the azeotropic agent and accelerates the reaction, in particular, by bringing low values of acid number to give a product of hydroxyl number 56 mgKOH / g and acid number 0, Example 10 Polyesterification is carried out on the apparatus and process described in Example 9, except that pentaerythritol and, in addition, caprolactone are used as the polyol. 1300 g of esterification residues from the production of dimethyl terephthalate, 200 g of caprolactone, 1500 g of diethylene glycol, 250 g of pentaerythritol are weighed into the flask. The transesterification is carried out at 180 DEG-220 DEG C. in the presence of nitrogen and for 6 h. mgKOH / g and acid value 0.4 mg KOH / g. and / or a low molecular weight reaction product carrier, characterized in that the transesterification and / or polyesterification is used as the acid component in part or in complete distillation. a residue from the production of terephthalic acid and / or dimethyl terephthalate. Printed by TSNP, n. Martin Price Kčs 2.40