PROCESS FOR THE CONTINUOUS PRODUCTION OF POLYOXYALKYLENE POLYOLS

Abstract

The invention relates to a process for producing a polyoxyalkylene polyol, comprising depositing an alkylene oxide onto an H-functional starter substance in the presence of a double metal cyanide (DMC) catalyst, wherein the alkylene oxide is dosed at the mass flow rate m(alkylene oxide), the H-functional starter substance is dosed at the mass flow rate m(starter substance), and the double metal cyanide (DMC) catalyst is dosed in a dispersant at the mass flow rate m(DMC) continuously into the reactor with the reaction volume V during the reaction, and the resulting reaction mixture is continuously removed from the reactor, and wherein the quotient of the sum of the mass flow rates Σ{dot over (m)} of {dot over (m)}(alkylene oxide), {dot over (m)}(starter substance) and {dot over (m)}(DMC) to give the reaction volume V in the steady state is greater than or equal to 1200 g/(h.Math.L).

Claims

1. A process for preparing a polyoxyalkylene polyol comprising addition of an alkylene oxide onto an H-functional starter substance in the presence of a double metal cyanide (DMC) catalyst; wherein the alkylene oxide with a mass flow {dot over (m)}(alkylene oxide), the H-functional starter substance with a mass flow {dot over (m)}(starter substance) and the double metal cyanide (DMC) catalyst in a dispersion medium with a mass flow {dot over (m)}(DMC) are during the reaction continuously metered into a reactor having a reaction volume V and the resulting reaction mixture is continuously removed from the reactor; and wherein the quotient of the sum of the mass flows Σ{dot over (m)}, composed of {dot over (m)}(alkylene oxide), {dot over (m)}(starter substance) and {dot over (m)}(DMC), and the reaction volume V in the steady state is not less than 1200 g/(h.Math.L).

2. The process as claimed in claim 1, wherein the quotient of the sum of the mass flows Σ{dot over (m)}, composed of {dot over (m)}(alkylene oxide), {dot over (m)}(starter substance) and {dot over (m)}(DMC), and the reaction volume V in the steady state is not less than 1500 g/(h.Math.L).

3. The process as claimed in claim 1, wherein the quotient of the sum of the mass flows Σ{dot over (m)}, composed of {dot over (m)}(alkylene oxide), {dot over (m)}(starter substance) and {dot over (m)}(DMC), and the reaction volume V in the steady state is not more than 4000 g/(h.Math.L).

4. The process as claimed in claim 1, wherein the reaction volume V is identical to the reactor volume V.sub.R..

5. The process as claimed in claim 1, wherein the polyoxyalkylene polyol comprises a polyether polyol.

6. The process as claimed in claim 1, wherein the concentration of the double metal cyanide (DMC) catalyst is 50 ppm or less, based on the sum of alkylene oxide, H-functional starter substance, dispersion medium and double metal cyanide (DMC) catalyst.

7. The process as claimed in claim 1, wherein the double metal cyanide (DMC) catalyst is obtained by reaction of an aqueous solution of a cyanide-free metal salt, an aqueous solution of a metal cyanide salt, an organic complex ligand and a complex-forming component.

8. The process as claimed in claim 7, wherein the complex-forming component is a polyether polyol having a number-average molecular weight of ≥500 g/mol, wherein the number-average molecular weight is calculated from the determined OH number.

9. The process as claimed in claim 7, wherein the organic complex ligand comprises one or more of dimethoxyethane, tert-butanol, 2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, ethylene glycol mono-tert-butyl ether and 3-methyl-3-oxetanemethanol.

10. The process as claimed in claim 1, wherein the H-functional starter substance comprises one or more of ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2-methylpropane-1,3-diol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane and di- and trifunctional polyether polyols.

11. The process as claimed in claim 1, wherein the dispersion medium is the same as the H-functional starter substance.

12. The process as claimed in claim 1, wherein the alkylene oxide is ethylene oxide, propylene oxide or a mixture of ethylene oxide and propylene oxide.

13. The process as claimed in claim 1, wherein the reaction temperature is 130° C. to 170° C.

14. The process as claimed in claim 1, wherein the reaction mixture continuously outflowing from the reactor is continuously transferred into a postreactor to reduce the content of free alkylene oxide.

15. The process as claimed in claim 1, wherein the quotient of the sum of the mass flows Σ{dot over (m)}, composed of {dot over (m)}(alkylene oxide), {dot over (m)}(starter substance) and {dot over (m)}(DMC), and the reaction volume V in the steady state is 1200 g/(h.Math.L) to 4000 g/(h.Math.L).

Description

EXAMPLES

[0144] OH numbers were determined according to the procedure of DIN 53240. Viscosities were determined by rotational viscometer (Physica MCR 51, Anton Paar) according to the procedure of DIN 53018.

[0145] The number-average M.sub.n and the weight-average M.sub.w of the molecular weight and the polydispersity index PDI (M.sub.w/M.sub.n) of the products was determined by gel permeation chromatography (GPC). The procedure of DIN 55672-1 was followed: “Gel permeation chromatography, Part 1—Tetrahydrofuran as eluent” (SECurity GPC System from PSS Polymer Service, flow rate 1.0 ml/min; columns: 2×PSS SDV linear M, 8×300 mm, 5 μm; RID detector). Polystyrene samples of known molar mass were used for calibration.

[0146] Raw Materials Used

[0147] Catalyst for alkylene oxide addition (DMC catalyst):

[0148] double metal cyanide catalyst, containing zinc hexacyanocobaltate, tert-butanol and polypropylene glycol having a number-average molecular weight of 1000 g/mol; described in WO-A 01/80994, example 6.

Example 1 (Comparative)

[0149] A continuously operated stainless steel pressure reactor having an available reactor volume V.sub.R. of 1.951 liters filled with a polyether polyol (OH functionality=2.82; OH number=48 mg KOH/g; propylene oxide/ethylene oxide ratio=89.5/10.5; containing 25 ppm DMC catalyst) had the following components metered into it at the reported mass flows at a temperature of 150° C. with stirring (800 rpm): [0150] propylene oxide at 817.50 g/h [0151] ethylene oxide at 95.51 g/h [0152] glycerol at 21.69 g/h [0153] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 3.83 g/h

[0154] The reaction mixture was continuously withdrawn from the pressure reactor while the reactor was always completely filled with liquid, and the reaction volume V therefore corresponded to the reactor volume V.sub.R. Completion of the reaction was effected by continuously transferring the withdrawn reaction mixture into a postreactor (tubular reactor having an internal volume of 1.0 L) temperature controlled to 100° C. After exiting the postreactor the obtained product was cooled to room temperature and then subjected to analytical examination. Table 1 reports the analytical values for a sample taken after a total reaction time corresponding to 12 residence times.

Example 2 (Comparative)

[0155] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 150° C.: [0156] propylene oxide at 1090.00 g/h [0157] ethylene oxide at 127.88 g/h [0158] glycerol at 28.92 g/h [0159] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 5.10 g/h

Example 3 (Comparative)

[0160] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 150° C.: [0161] propylene oxide at 1362.50 g/h [0162] ethylene oxide at 159.85 g/h [0163] glycerol at 36.15 g/h [0164] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 6.38 g/h

Example 4 (Comparative)

[0165] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 130° C.: [0166] propylene oxide at 817.50 g/h [0167] ethylene oxide at 95.51 g/h [0168] glycerol at 21.69 g/h [0169] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 3.83 g/h

Example 5 (Comparative)

[0170] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 130° C.: [0171] propylene oxide at 1362.50 g/h [0172] ethylene oxide at 159.85 g/h [0173] glycerol at 36.15 g/h [0174] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 6.38 g/h

Example 6 (Comparative)

[0175] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 130° C.: [0176] propylene oxide at 1635.00 g/h [0177] ethylene oxide at 191.82 g/h [0178] glycerol at 43.38 g/h [0179] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 7.66 g/h

Example 7

[0180] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 130° C.: [0181] propylene oxide at 3270.00 g/h [0182] ethylene oxide at 383.63 g/h [0183] glycerol at 86.76 g/h [0184] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 15.31 g/h

Example 8

[0185] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 150° C.: [0186] propylene oxide at 3270.00 g/h [0187] ethylene oxide at 383.63 g/h [0188] glycerol at 86.76 g/h [0189] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 15.31 g/h

Example 9

[0190] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 160° C.: [0191] propylene oxide at 3270.00 g/h [0192] ethylene oxide at 383.63 g/h [0193] glycerol at 86.76 g/h [0194] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 15.31 g/h

Example 10

[0195] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 150° C.: [0196] propylene oxide at 3633.33 g/h [0197] ethylene oxide at 426.26 g/h [0198] glycerol at 96.40 g/h [0199] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 17.01 g/h

Example 11

[0200] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 150° C.: [0201] propylene oxide at 2180.00 g/h [0202] ethylene oxide at 255.75 g/h [0203] glycerol at 57.84 g/h [0204] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 10.21 g/h

Example 12

[0205] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 150° C.: [0206] propylene oxide at 3924.00 g/h [0207] ethylene oxide at 460.36 g/h [0208] glycerol at 104.11 g/h [0209] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 18.37 g/h

Example 13

[0210] The procedure of example 1 (comparative) was followed with the exception that the following components were metered at the reported mass flows at a temperature of 150° C.: [0211] propylene oxide at 4562.79 g/h [0212] ethylene oxide at 535.30 g/h [0213] glycerol at 121.06 g/h [0214] dispersion of 0.00613 g of DMC catalyst in 1 g of propylene glycol at 21.36 g/h

[0215] The values reported in table 1 for Σ{dot over (m)}/V [g/(h.Math.L)] (=quotient of the sum of the mass flows Σ{dot over (m)}, composed of {dot over (m)}(alkylene oxide), {dot over (m)}(starter substance) and {dot over (m)}(DMC), and the reaction volume V in the steady state) are calculated as the quotient of the sum of the mass flows (g/h) reported in the abovementoned examples and the reaction volume of 1.951 liters.

[0216] The residence times (VWZ) reported in table 1 are defined as the quotient of the reaction volume V and the outflowing volume flow. The volume flow is calculated as the quotient of the sum of the mass flows and the density of the product at the respective reaction temperature:

[0217] T=130° C.: density=0.9486 g/ml

[0218] T=150° C.: density=0.9304 g/ml

[0219] T=160° C.: density=0.9205 g/ml

TABLE-US-00001 TABLE 1 Summary of results Viscosity 25° C./ Σ{dot over (m)}/V VWZ Temperature corrected PDI Example [g/(h .Math. L)] [min] [° C.] [mPas]* [M.sub.wM.sub.n]  1 (comp.) 481 116 150 703 1.18  2 (comp.) 642 87 150 694 1.13  3 (comp.) 802 70 150 694 1.15  4 (comp.) 481 118 130 700 1.13  5 (comp.) 802 71 130 693 1.12  6 (comp.) 963 59 130 699 1.10  7 1925 30 130 699 1.17  8 1925 29 150 708 1.15  9 1925 29 160 710 1.18 10 2139 26 150 721 1.15 11 1283 43 150 721 1.15 12 2310 24 150 717 1.16 13 2686 21 150 723 1.15 *Corrected viscosity (25° C.) = measured viscosity (25° C.) + 13 *(OH number − 48) Comp. = comparative example