Catalysts for polyesterol synthesis

Abstract

This invention relates to catalysts for polyesterol synthesis and the use of a di-thio compound as catalyst for the production of polyester-polyols.

Claims

1. A process of producing a polyesterol, the process comprising: catalyzing a reaction with a compound of formula I
R1-CH.sub.2SSCH.sub.2R2(I), wherein R1 is selected from the group consisting of Ar1 and (CH.sub.2).sub.xCOOH, wherein x is 0, 1, 2 or 3; and R2 is selected from the group consisting of Ar2 and (CH.sub.2).sub.yCOOH, wherein y is 0, 1, 2 or 3, wherein Ar1 and Ar2 are substituted or unsubstituted phenyl; wherein said reaction is a reaction of at least one di-carboxylic acid with at least one diol or polyol; and wherein an amount of the compound of formula I in a reaction mixture is between 1 to 10.sup.4 ppm.

2. The process of claim 1, wherein R1 is (CH2)x-COOH, wherein x is 0, 1, 2 or 3; and R2 is (CH2)y-COOH, wherein y is 0, 1, 2 or 3.

3. The process of claim 1, wherein R1 is Ar1 and R2 is Ar2.

4. The process of claim 1, wherein x and y are 1.

5. The process of claim 1, wherein R1 and R2 are unsubstituted phenyl.

6. The process of claim 1, wherein an amount of the compound of formula I in a reaction mixture is between 1 to 10.sup.3 ppm.

7. The process of claim 1, wherein the at least one di-carboxylic acid is selected from the group consisting of malonic acid, succinic acid, glutaric acid, adipic acid and pimelic acid.

8. The process of claim 1, wherein the at least one diol is selected from the group consisting of monoethylene glycol, diethylene glycol, propane diol, 1,4-butane diol, and trimethylol propane (TMP).

9. The process of claim 1, wherein the reaction is performed at a temperature between 80 and 300 C.

10. A process of producing a polyurethane, the process comprising reacting a polyesterol obtainable from the process of claim 1.

Description

EXAMPLES

(1) Determination of Viscosity

(2) The viscosity of the polyols was determined at 25 C. according to DIN EN ISO 3219 (1994) with a rotational viscosimeter Rheotec RC 20, using spindle CC 25 DIN (diameter of spindle: 12.5 mm; interior diameter of measuring cylinder: 13.56 mm) at a shear rate of 50 l/s.

(3) Determination of Hydroxyl Number

(4) The hydroxyl number were determined according to the phthalic anhydride method DIN 53240 (1971-12) and are given in mg KOH/g.

(5) Determination of the Acid Number

(6) The acid number was determined according to DIN EN 1241 (1998-05) and is given in mg KOH/g.

(7) Synthesis of the Polyols

(8) The following catalysts were used: Titanium(IV) butoxide CAS: 5593-70-4 (TTB) Tin(II) 2-ethylhexanoate CAS: 301-10-0 (SDO)

Example 1 (Comparison, Standard Catalysis)

(9) A 4 l flask equipped with thermometer, nitrogen inlet, heating mantle, distillation column and stirrer was charged with 1887.6 g of 1,6-hexanoic diacid (adipic acid), 452.8 g of monoethylene glycol, 657.4 g of 1,4-butane diol and 25 mg of titanium(IV)butoxide and heated to 120 C. The reaction mixture was further heated to 240 C. and the condensation water was continuously distilled off until an acid number of 1 mg KOH/g was reached. A polyester polyol with a hydroxyl number of 53.26 mg KOH/g, an acid number of 0.708 mg KOH/g and a viscosity of 738 mPas at 75 C. was obtained.

Example 2 (Dithio Propionic Acid)

(10) A 4 l flask equipped with thermometer, nitrogen inlet, heating mantle, distillation column and stirrer was charged with 1887.7 g of 1,6-hexanoic diacid (adipic acid), 452.8 g of monoethylene glycol, 657.4 g of 1,4-butane diol and 250 mg of 3,3-dithio propionic acid and heated to 120 C. The reaction mixture was further heated to 240 C. and the condensation water was continuously distilled off until an acid number of 1 mg KOH/g was reached. A polyester polyol with a hydroxyl number of 55.66 mg KOH/g, an acid number of 0.292 mg KOH/g and a viscosity of 974.3 mPas at 75 C. was obtained.

Example 3 (Dibenzyldidisulfide)

(11) A 4 l flask equipped with thermometer, nitrogen inlet, heating mantle, distillation column and stirrer was charged with 1887.7 g of 1,6-hexanoic diacid (adipic acid), 452.8 g of monoethylene glycol, 657.4 g of 1,4-butane diol and 250 mg of dibenzyldisulfide and heated to 120 C. The reaction mixture was further heated to 240 C. and the condensation water was continuously distilled off until an acid number of 1 mg KOH/g was reached. A polyester polyol with a hydroxyl number of 56.38 mg KOH/g, an acid number of 0.339 mg KOH/g and a viscosity of 849.2 mPas at 75 C. was obtained.

Example 4 (Autocatalytic)

(12) A 4 l flask equipped with thermometer, nitrogen inlet, heating mantle, distillation column and stirrer was charged with 1887.7 g of 1,6-hexanoic diacid (adipic acid), 452.8 g of monoethylene glycol, 657.4 g of 1,4-butane diol and 250 mg of dibenzyldisulfide and heated to 120 C. The reaction mixture was further heated to 240 C. and the condensation water was continuously distilled off until an acid number of 2 mg KOH/g was reached. A polyester polyol with a hydroxyl number of 52 mg KOH/g, an acid number of 1.73 mg KOH/g and a viscosity of 889.4 mPas at 75 C. was obtained.

(13) The examples show that the inventive compounds may be used as catalysts in the manufacture of polyesterols.

(14) FIG. 1 shows reaction kinetic data of polyesterol synthesis experiments with different catalysts. It can be seen that the use of the inventive, sulfur-containing compounds results in faster reactions, thus the inventive sulfur-containing compounds have a catalytic activity in the manufacture of polyesterols.