CS200893B1 - Method of production of polyester polyols - Google Patents

Abstract

The invention relates to the improvement of the production of polyester polyols, whereby the modification of the technological conditions improves the use of low-boiling glycols as raw materials while simultaneously preventing losses, especially by entrainment and entrainment by reaction water. The reaction mixture, heated to a temperature of 110 to 250 °C, contains a polyesterification catalyst, while the resulting vapor phase is gradually cooled and the condensed components are returned to the reaction mixture and the discarded vapor phase is condensed, usually phase separated, while the organic liquid phase is also returned to the reaction mixture.

Description

- 1 - 200 093

BACKGROUND OF THE INVENTION The present invention relates to an improvement in the preparation of polyester polyols, whereby the use of low-grade glycols as effervescent materials is also adhered to by modifying the temperature conditions, while avoiding losses, in particular by entrainment and shearing of the reaction water.

Polyester polyols are prepared by reacting dicarboxylic acids and / or iodides with di- or polybasic alcohols. The amount of alcohols is chosen so as to provide the desired hydroxyl number of the polyester polyol, with an acidity number of more than 1 mg KOH / g. Polyesterifene is carried out in the presence of catalysts which reduce the reaction time, respectively. reaction temperature. The greatest effect on the ability of polyesterification to eliminate water from the reaction medium. They are usually removed by nitrogen, carbon dioxide, or azeotropic distillation with toluene, xylone, or other hydrogen atoms. The most serious problem here is for the water to be removed to contain the least amount of alcohols, especially ethylene glycol, in the soaked reaction rate.

According to the invention, the process for the preparation of polyester polyols from dicarboxylic acids and / or their anhydrides and ethylene glycol and other dihydric and / or polyhydric alcohols and the presence of catalysts, usually in the presence of water entrainers, is carried out by heating the reaction mixture to a temperature of 110 to 250C comprises a polyesterification catalyst in an amount of 10% to 1% by weight, based on the starting material, preferably titanium and / or zirconium, resulting in a vapor phase of 50-3000 h -1, preferably 200-2,500 h 1 for gradual cooling of the temperature corresponding to a paroial pressure of ethylene glycol 133 of 32 to 2666.4 Pa, preferably to a temperature of 90 to 105 ° C, the condensed components are returned to the reaction mixture with gradual cooling and the evacuating vapor phase is condensed , typically the phases are separated while the organic liquid phase is also returned to the reaction mixture.

The process of this invention achieves not only a small amount of ethylene glycol in the process of drainage from the process, which is of great importance from the ecological point of view, but gains other advantages in the process economy. In addition to the saved glycol, the process with uniformity of the reaction components is more uniform and more refined. The polyol polyvalent, a hydroxyl number, is practically constant and does not need to be treated during the process by the addition of some dibasic glycol. Also, the mechanical properties of the polystyrene obtained are more uniform and better than when the final polyester polyol is modified.

In addition to ethylene glycol, other di- and polyol is used as starting materials either alone or in mixtures, for example propyl glycol, diethylene glycol, triethylene glycol, 1,4-butylene glycol, glycerin, methylglycerin, trimethylpropane, pentaerythriol as well as some sugars. The dicarboxylic acids include adipic acid, phthalic acid, terephthalic acid, corkic acid, sebacic acid, glutaric acid, and optionally anhydrides. However, these types do not limit the possibility of using other di- or polycarboxylic acids.

Furthermore, a large number of catalysts for base and zirconium, e.g., titanium tetrahalides, lanthanum titanate, titanyl oxalate, tetraalkyl titanate, quaternary, amine and alkali salts or alkali metal salts of earthithanalkoxides, are proposed for the polycondensation reaction. These types of catalysts are only basic types, and in the process of the invention other types of catalysts known to one another can be combined with one another.

In order to favorably influence the reaction conditions, it is expedient to permanently remove the resulting reaction water, which is most often carried out either by blowing, which however causes some losses on the components, usually by azeotropic distillation with a water-forming substance, such as a binary azeotropic mixture, e.g. toluene, xylenes, benzene and the like.

The reaction conditions as well as the amount of catalyst are chosen such that the amount of reaction water produced is as large as possible, which also substantially affects the utilization of the equipment as well as the thermal equipment present. However, care must be taken that the reaction conditions are such that there is no increase in the formation of byproducts, and as low as possible the amount of low-feces in the discharged water, the separation device can usually be of a simple type, tubular, with it ensures that the desired low-boiling glycol parole pressure is achieved. However, it is desirable that the vapor temperature of the separator does not exceed a substantial value of 105 ° C. However, this temperature is also dependent on the type of low molecular weight diols used. A regulator that maintains the temperature in the separator casing at the desired height can be used to provide low glycol content. The exemplary embodiments illustrate more specific application conditions of the invention. Example 1

The esterification apparatus consists of a four-necked flask equipped with a stirrer, a contact thermometer, an inert gas inlet and a cartridge with a charge associated with the azeotropic charge.

500 g of adipic acid, 230 g of monoethylene glycol, 0.07 g of trebutyl titanate, 0.2 g of triethylamine and 35 g of xylene were weighed into a flask. The mixture is gradually heated to a temperature of 220 ° C while removing the reaction water by azeotropic distillate xylene. The vapors of the azeotrope blend run off a 2.5 µm Pruuer column, which is 3 - 3,000,893 filled with Haschig books (0.2 µm diameter) to a height of 30 µm. The vapors displaced at the top of the column are 95 ° C. The heating of the reaction is controlled so that the maximum vapor depletion rate is 800 h. Under these conditions, the column has a deliberate split ability, the ethylene glycol drift to the reaction water is below 0.1 wt%. Upon reaching the polyester polyol number below 1 mg KOH / g, a substantial portion of the xylene is blown off by blowing off the inert gas, the residue is removed by distillation under a vacuum of 10 kPa at 150 ° C. The reaction time of the polyester emulsion is 5 hours, the removal of xylene takes 1.5 hours. Sulfur, a pale yellow polyester polyol with an acid number of 0.6 mg KOH / g, a hydroxyl group of 55.6 mg KOH / g, a water content of 0.05% by weight, is obtained. and xylene content below 0.1 wt. Example 2

The esterification apparatus is as in Example 1. 500 g of adipic acid, 230 g of monoethylene glycol, 0.1 g of tetrabutyl titanate, 0.1 g of lead octoate and 35 g of xylene are weighed into a four-necked sulfonation flask. The same column as in Example 1 was used to separate ethylene glycol entrained in the azeotrope of water with xylene, but the filling height was only 10 cm. By increasing the volume ratio of the couple to a length of 2400 h @ -1, the column capacity is substantially reduced, the ethylene glycol content of the reaction water being 1.4 wt%. The polyesterification time is increased to 6.5 hours and the polyester polyol obtained has a hydroxyl number of less than 50.5 mg KOH / g, an acid number of 0.6 mg KOH / g, an xylene content of 0.1% by weight. Example 3

500 g of adipic acid, 127 g of monoethylene glycol, 156 g of 1,4-butylene glycol, 0.1 g of tetrabutyl titanate, 0.1 g of lead octoate, 0.1 g of triethylamine and 40 g of xylene are weighed into a 4-necked flask. To collect entrained ethylene glycol, a column was used as in Example 1, the filling height was chosen so that the maximum bulk density of the fill was 1000 h ** 1 and the temperature of the same pair at the top of the column was 105 ° C.

The ethylene glycol content of the reaction water is 0.15% by weight, the polyesterification time is 5 hours.

After reaching the acid number of the polyester polyol below 1 mg KOH / g, the xylene is removed by the procedure described in Example 1. The prepared polyester polyol has an acid number of 0.7 mg KOH / g, a hydroxyl number of 55.3 mg KOH / g, a viscosity at 75 ° C of 0.7 Pas, a xylene content of 0.1% by weight. Example 4

The polyester esterification device consists of a stainless steel boiler equipped with a stirrer, a hopper and a drain valve, a heating, a temperature control and a riser containing Raschig rings. 500 parts of adipic acid, 127 parts of monoethylene glycol, 181 parts of diethylene glycol, 0.5 parts of tetra-

Claims (1)

- 4 - 200 803 of toutyltitanate, 0.5 parts of tetrnbutylzirconate and 35 parts of xylene. Polyestarification was carried out at a temperature of 130 to 230 ° C. A pair of paddles at a maximum of 2240 h ”1. At the foot of the footrest aa temperature of 95 ° C was maintained by regulating the vapor and beach temperatures. Under these conditions, the monoethylene glycol in the separated reaction water is below 0.5 ¢, the polyeetherification time is 18 hours. After removal of xylene, the product has a hydroxyl content of 55 mg of COH / g, a kyaloate of 0.5 mg of KOH / g, and a water content of 0.06% by weight. and xylene below 0.1 wt. The product, as well as from the foregoing examples, is suitable for the preparation of an integral foam especially for the shoe industry. for water entrainers, characterized in that the reaction temperature heated to 110-250 ° C comprises a polyeetification catalyst of 10 to 1% by weight, calculated on the starting materials, and preferably on the basis of titanium and / or zirconium, resulting in a vapor phase and a in addition to 50 to 3,000 h -1, preferably 200 to 2,500 h "", by volume, to gradual cooling to a temperature corresponding to an ethylene glycol vapor pressure of 133.32 to 2666.4 Pa, and preferably to a temperature of 90 to 105 ° C , under the condensation, the condensed components aa return to the reaction mixture and the vapor phase aa it is condensed, usually and phase separated, and the organic liquid phase is also introduced into the reaction mixture.