WO2021110691A1 - Process for producing polyether carbonate polyols - Google Patents

Abstract

The present invention relates to a process for producing polyether carbonate polyols comprising the step of reacting alkylene oxide with carbon dioxide in the presence of an H-functional starter compound and double metal cyanide catalyst, characterized in that (α) a subamount of H-functional starter substance and/or suspension medium containing no H-functional groups is initially charged in a reactor in each case together with DMC catalyst, (β) the mixture from step (α) is admixed with a subamount of alkylene oxide at temperatures of 90°C to 150°C and wherein the addition of the alkylene oxide is then interrupted, (γ) alkylene oxide, carbon dioxide and a mixture containing unactivated double metal cyanide catalyst and an H-functional starter compound, wherein the H-functional starter compound is a polyol having a number-average molar mass according to DIN 55672-1 of 550 to 2000 g/mol, is continuously added to the mixture resulting from (β).

Description

Process for the preparation of polyether carbonate polyols

The present invention relates to a process for the production of polyether carbonate polyols from H-functional starter compound, alkylene oxide and carbon dioxide in the presence of a double metal cyanide (DMC) catalyst. It also relates to polyether carbonate polyols obtained by the process according to the invention.

The production of polyether carbonate polyols by catalytic conversion of alkylene oxides (epoxides) and carbon dioxide in the presence of H-functional starter substances ("starters") has been intensively investigated for more than 40 years (e.g. Inoue et al, Copolymerization of Carbon Dioxide and Epoxide with Organometallic Compounds; Die Makromolekulare Chemie 130, 210-220, 1969). This reaction is shown schematically in scheme (I), where R is an organic

A radical such as alkyl, alkylaryl or aryl, which in each case can also contain heteroatoms such as, for example, O, S, Si, etc., and where e, f and g are an integer number, and where the product shown here in scheme (I) is the polyether carbonate polyol should only be understood to mean that blocks with the structure shown can in principle be found in the polyether carbonate polyol obtained, but the order, number and length of the blocks and the OH functionality of the starter can vary and not to that shown in scheme (I) Polyether carbonate polyol is limited. This reaction (see scheme (I)) is ecologically very advantageous, since this reaction represents the conversion of a greenhouse gas such as CO2 into a polymer. Another product, actually a by-product, is the cyclic carbonate shown in scheme (I) (for example for R = CH3 propylene carbonate).

O

Starter OH + (e + f + g) ZL + (e + g) C0 ₂

R.

EP 0 222 453 A2 discloses a process for the production of polycarbonates from alkylene oxides and carbon dioxide using a catalyst system composed of DMC catalyst and a cocatalyst such as zinc sulfate. The polymerization is initiated by bringing part of the alkylene oxide into contact with the catalyst system once. Only then are the remainder of the alkylene oxide and the carbon dioxide metered in simultaneously. The amount of 60% by weight of alkylene oxide relative to the H-functional starter compound specified in EP 0222453 A2 for the activation step in Examples 1 to 7 is high and has the disadvantage that this is necessary for industrial applications due to the high exothermic nature of the homopolymerization of Alkylene oxides poses a safety risk. WO 2016/079065 A1 discloses a continuous process for the production of polyether carbonate polyols, a mixture of H-functional starter substance and activated DMC catalyst, alkylene oxide and carbon dioxide being metered in. However, no information is given on the free alkylene oxide concentration. For the production of polyether carbonate polyols on an industrial scale, there is a need for a method for carrying out the reaction in which product quality and safety are guaranteed.

The object was therefore to provide a process for the preparation of polyether carbonate polyols which is distinguished by a low concentration of free alkylene oxide in the process, a narrow molar mass distribution of the polyether carbonate polyols obtained and a good selectivity. In addition, the process should lead to shorter residence times, which makes it possible to reduce the reactor volume and lower investment costs.

It has surprisingly been found that the object according to the invention is achieved by a process for producing polyether carbonate polyols, comprising the step of reacting alkylene oxide with carbon dioxide in the presence of an H-functional starter compound and double metal cyanide catalyst, characterized in that

(a) a partial amount of H-functional starter substance and / or suspending agent, which does not contain any H-functional groups, is placed in a reactor together with DMC catalyst,

(ß) a partial amount of alkylene oxide is added to the mixture from step (a) at temperatures of 90 to 150 ° C, and the addition of the alkylene oxide is then interrupted,

(g) Alkylene oxide, carbon dioxide and a mixture containing non-activated double metal cyanide catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molar mass according to DIN 55672-1 of 550 to 2000 g / mol, continuously is added to the mixture resulting from (ß).

In a preferred embodiment, the invention relates to a process for the production of polyether carbonate polyols, comprising the step of reacting alkylene oxide with carbon dioxide in the presence of an H-functional starter compound and double metal cyanide catalyst, characterized in that

(a) a partial amount of H-functional starter substance and / or suspending agent which does not contain any H-functional groups is placed in a reactor, optionally together with DMC catalyst, (β) to the mixture from step (a) a partial amount of alkylene oxide at temperatures from 90 to

150 ° C is added, and the addition of the alkylene oxide is then interrupted, (g) Alkylene oxide, carbon dioxide and a mixture containing non-activated double metal cyanide catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molar mass according to DIN 55672-1 of 550 to 2000 g / mol, continuously is added to the mixture resulting from (ß),

(d) the reaction mixture obtained in step (g) remains in the reactor or is continuously transferred to a postreactor, the content of free alkylene oxide in the reaction mixture being reduced by means of postreaction under the chosen process conditions (including temperature and residence time). It is characteristic of the polyether carbonate polyols produced according to the invention in the presence of a double metal cyanide (DMC) catalyst that these also contain ether groups between the carbonate groups. With regard to formula (Ia), this means that the ratio of e / f is preferably from 2: 1 to 1:20, particularly preferably from 1.5: 1 to 1:10.

To step (a):

The process according to the invention for producing polyether carbonate polyols by adding alkylene oxide and carbon dioxide onto H-functional starter substance comprises a step (a).

H-functional starter substance and / or a suspending agent which does not contain any H-functional groups can first be initially introduced into the reactor; a portion of the H-functional starter substance is preferably initially introduced. An amount of DMC catalyst, which is preferably not activated, can then be added to the reactor. The order in which they are added is not critical. It is also possible to first fill the DMC catalyst and then the suspension medium into the reactor. Alternatively, the DMC catalyst can also first be suspended in the inert suspension medium and then the suspension can be filled into the reactor. The suspension medium provides a sufficient heat exchange surface with the reactor wall or cooling elements built into the reactor, so that the released heat of reaction can be dissipated very well. In addition, the suspension medium provides heat capacity in the event of a cooling failure, so that in this case the temperature can be kept below the decomposition temperature of the reaction mixture.

The suspension agents used do not contain any H-functional groups. All polar-aprotic, weakly polar-aprotic and non-polar-aprotic solvents, which in each case do not contain any H-functional groups, are suitable as suspending agents. Mixtures of two or more of these suspending agents can also be used as suspending agents. Be exemplary The following polar aprotic solvents are mentioned at this point: 4-methyl-2-oxo-1,3-dioxolane (hereinafter also referred to as cyclic propylene carbonate or cPC), 1,3-dioxolan-2-one (hereinafter also referred to as cyclic Ethylene carbonate or cEC), acetone, methyl ethyl ketone, acetonitrile, nitromethane, dimethyl sulfoxide, sulfolane, dimethylformamide, dimethylacetamide and A-methylpyrrolidone. The group of non-polar and weakly polar aprotic solvents includes, for example, ethers such as dioxane, diethyl ether, methyl tert-butyl ether and tetrahydrofuran, esters such as ethyl acetate and butyl acetate, hydrocarbons such as pentane, n-hexane, benzene and alkylated benzene derivatives (e.g. toluene, xylene, ethylbenzene) and chlorinated hydrocarbons such as chloroform, chlorobenzene, dichlorobenzene and carbon tetrachloride. 4-Methyl-2-oxo-1,3-dioxolane, 1,3-dioxolan-2-one, toluene, xylene, ethylbenzene, chlorobenzene and dichlorobenzene and mixtures of two or more of these suspending agents are preferred as suspending agents; 4 is particularly preferred -Methyl-2-oxo-1,3-dioxolane and 1,3-dioxolan-2-one or a mixture of 4-methyl-2-oxo-1,3-dioxolane and 1,3-dioxolan-2-one.

Also suitable as suspending agents are aliphatic lactones, aromatic lactones, lactides, cyclic carbonates with at least three optionally substituted methylene groups between the oxygen atoms of the carbonate group, aliphatic cyclic anhydrides and aromatic cyclic anhydrides.

Aliphatic or aromatic lactones in the context of the invention are cyclic compounds containing an ester bond in the ring, preferably 4-membered ring lactones such as ß-propiolactone, ß-butyrolactone, ß-isovalerolactone, ß-caprolactone, ß-isocaprolactone, ß-methyl-ß-valerolactone ,

5-membered ring lactones, such as g-butyrolactone, g-valerolactone, 5-methylfuran-2 (3H) -one, 5-methylidenedihydrofuran-2 (3H) -one, 5-hydroxyfuran-2 (5H) -one, 2-benzofuran -l (3H) -one and 6- methy-2-benzofuran-1 (3H) -one, 6-membered ring lactones, such as d-valerolactone, 1,4-dioxan-2-one, dihydrocoumarin, 1H-isochromene-1 - one, 8H-pyrano [3,4-b] pyridine-8-one, 1,4-dihydro-3H-isochromen-3-one, 7,8-dihydro-5H-pyrano [4,3-b] pyridines -5-one, 4-methyl-3,4-dihydro-1H-pyrano [3,4-b] pyridine-1-one, 6-hydroxy-3,4-dihydro-1H-isochromen-1-one, 7 -Hydroxy-3,4-dihydro-2H-chromen-2-one, 3-ethyl-1H-isochromen-1-one, 3- (hydroxymethyl) -1H-isochromen-1-one, 9-hydroxy-1H, 3H -benzo [de] isochromen-l-one, 6,7-dimethoxy-l, 4-dihydro-3H-isochromen-3-one and 3-phenyl-3,4-dihydro-lH-isochromen-l-one,

7-membered ring lactones, such as e-caprolactone, l, 5-dioxepan-2-one, 5-methyloxepan-2-one, oxepane-2,7-dione, thiepan-2-one, 5-chlorooxepan-2-one, (4.V) -4- (propan-2-yl) oxcpan-2-one, 7-butyloxepan-2-one, 5- (4-aminobutyl) oxepan-2-one, 5-phenyloxepan-2-one, 7 -Hexyloxepan-2-one, (5, S'.7, Y) -5-methyl- 7- (propan-2-yl) oxepan-2-one, 4-methyl-7- (propan-2-yl) oxepan-2-one, higher-membered ring lactones, such as (7 £) -oxacycloheptadec-7-en-2-one.

E-caprolactone and dihydrocoumarin are particularly preferred. Lactides for the purposes of the invention are cyclic compounds containing two or more ester bonds in the ring, preferably glycolide (1,4-dioxane-2,5-dione), L-lactide (L-3,6-dimethyl-

1,4-dioxane-2,5-dione), D-lactide, DL-lactide, mesolactide and 3-methyl-1,4-dioxane-2,5-dione, 3-hexyl-6-methyl-1,4-dioxane -2,5-dione, 3,6-di (but-3-en-1 -yl) -1, 4-dioxane-2,5-dione (in each case including optically active forms). L-lactide is particularly preferred.

Cyclic carbonates with at least three optionally substituted methylene groups between the oxygen atoms of the carbonate group are preferably trimethylene carbonate, neopentyl glycol carbonate (5,5-dimethyl-1,3-dioxan-2-one), 2,2,4-trimethyl-1,3-pentanediol carbonate,

2.2-dimethyl-1,3-butanediol carbonate, 1,3-butanediol carbonate, 2-methyl-1,3-propanediol carbonate, 2,4-pentanediol carbonate, 2-methyl-butane-1,3-diol carbonate, TMP monoallyl ether carbonate,

Pentaerythritol diallyl ether carbonate, 5- (2-hydroxyethyl) -1, 3-dioxan-2-one, 5- [2- (benzyloxy) ethyl] -

1.3-dioxan-2-one, 4-ethyl-l, 3-dioxolan-2-one, l, 3-dioxolan-2-one, 5-ethyl-5-methyl-l, 3-dioxan-2-one,

5.5 -Diethyl- 1, 3-dioxan-2-one, 5-methyl-5-propyl- 1, 3 -dioxan-2-one, 5 - (phenylamino) - 1, 3 -dioxan-2-one and 5, 5-dipropyl-1,3-dioxan-2-one. Trimethylene carbonate and neopentyl glycol carbonate are particularly preferred.

Cyclic anhydrides are preferably maleic anhydride, phthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, diphenic anhydride, tetrahydrophthalic anhydride,

Methyl tetrahydrophthalic anhydride, norbomene diacid anhydride and their chlorination products, succinic anhydride, glutaric anhydride, diglycolic anhydride, 1,8-naphthalic anhydride, succinic anhydride, dodecenylsuccinic anhydride, tetradecenylsuccinic anhydride,

Hexadecenylsuccinic anhydride, octadecenylsuccinic anhydride, 3- and 4- nitrophthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride,

Itaconic anhydride, dimethyl maleic anhydride, allyl norbomene diacid anhydride, 3-methylfuran-2,5-dione, 3-methyldihydrofuran-2,5-dione, dihydro-2H-pyran-2,6 (3H) -dione, 1,4-dioxane-2,6 -dione, 2H-pyran-2,4,6 (3H, 5H) -trione, 3-ethyldihydrofuran-2,5-dione, 3-methoxydihydrofuran-2,5-dione, 3- (prop-2-en-l -yl) dihydrofuran-2,5-dione, N- (2,5-

Dioxotetrahydrofuran-3-yl) formamide and 3 [(2E) -but-2-en-1-yl] dihydrofuran-2,5-dione. Succinic anhydride, maleic anhydride and phthalic anhydride are particularly preferred.

A mixture of two or more of the suspension agents mentioned can also be used as suspending agents. At least one compound selected from the group consisting of 4-methyl-2-oxo-1,3-dioxolane, 1,3-dioxolan-2-one, acetone, methyl ethyl ketone, acetonitrile, nitromethane is most preferred as the suspending agent in step (a) , Dimethyl sulfoxide, sulfolane, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dioxane, diethyl ether, methyl tert-butyl ether, tetrahydrofuran, ethyl acetate, butyl acetate, pentane, n-hexane, benzene, toluene, xylene, ethylbenzene, chloroform, chlorobenzene, carbon tetrachlorobenzene , e-caprolactone, dihydrocoumarin, trimethylene carbonate, Neopentyl glycol carbonate, 3,6-dimethyl-1,4-dioxane-2,5-dione, succinic anhydride, maleic anhydride and phthalic anhydride are used.

In one embodiment of the invention, in step (a) a suspension medium which does not contain any H functional groups is initially introduced into the reactor, optionally together with DMC catalyst, and no egg-functional starter substance is initially introduced into the reactor. Alternatively, in step (a), a suspension medium which does not contain any egg-functional groups and, in addition, a portion of the egg-functional starter substance (s) and, if appropriate, DMC catalyst can be placed in the reactor.

The DMC catalyst is preferably used in an amount such that the DMC catalyst content in the reaction product resulting from step (g) is 10 to 10,000 ppm, particularly preferably 20 to 5000 ppm and most preferably 50 to 500 ppm.

In a preferred embodiment, in step (a) in the resulting mixture (i) from a portion of the H-functional starter substance and / or suspending agent and (ii) DMC catalyst at a temperature of 90 to 150 ° C, particularly preferably 100 Up to 140 ° C inert gas (for example argon or nitrogen), an inert gas-carbon dioxide mixture or carbon dioxide is introduced and a reduced pressure (absolute) of 10 mbar to 800 mbar, particularly preferably 50 mbar to 200 mbar, is applied at the same time.

In an alternative preferred embodiment, in step (a) the resulting mixture (i) of a portion of the H-functional starter substance (s) and / or suspending agent and (ii) DMC catalyst at a temperature of 90 to 150 ° C, in particular preferably from 100 to 140 ° C at least once, preferably three times with 1.5 bar to 10 bar (absolute), particularly preferably 3 bar to 6 bar (absolute) of an inert gas (for example argon or nitrogen), an inert gas-carbon dioxide mixture or Carbon dioxide is applied and the overpressure is then reduced to approx. 1 bar (absolute).

The DMC catalyst can be added in solid form or as a suspension in a suspending agent or in a mixture of at least two suspending agents.

In a further preferred embodiment, in step (a)

(a-I) a subset of the H-functional starter substance and / or suspending agent presented and

(a-II) the temperature of the partial amount of the H-functional starter substance and / or the suspending agent is brought to 50 to 200 ° C., preferably 80 to 160 ° C., particularly preferably 100 to 140 ° C. and / or the pressure in the reactor is less than 500 mbar, preferably 5 mbar to 100 mbar, where appropriate, an inert gas stream (for example of argon or nitrogen), an inert gas-carbon dioxide stream or a carbon dioxide stream is passed through the reactor, wherein the double metal cyanide catalyst is added to the partial amount of the H-functional starter substance and / or suspending agent in step (aI) or immediately thereafter in step (a-II), and wherein the suspending agent does not contain any H-functional groups.

To step (ß):

Step (ß) is used to activate the DMC catalyst. This step (β) is preferably carried out under a carbon dioxide atmosphere. Activation in the context of this invention is a step in which a partial amount of alkylene oxide is added to the DMC catalyst suspension at temperatures of 90 to 150 ° C and the addition of the alkylene oxide is then interrupted, with the development of heat due to a subsequent exothermic chemical reaction which can lead to a temperature spike (“hotspot”) and a pressure drop in the reactor is observed due to the conversion of alkylene oxide and possibly CO2. The process step of activation is the period of time from the addition of the partial amount of alkylene oxide, optionally in the presence of CO 2, to the DMC catalyst until the development of heat occurs. If appropriate, the partial amount of the alkylene oxide can be added to the DMC catalyst in several individual steps, if appropriate in the presence of CO 2, and the addition of the alkylene oxide can then be interrupted in each case. In this case, the process step of activation comprises the time span from the addition of the first partial amount of alkylene oxide, optionally in the presence of CO2, to the DMC catalyst until the development of heat occurs after the addition of the last partial amount of alkylene oxide. In general, the activation step can be preceded by a step for drying the DMC catalyst and optionally the H-functional starter substance at elevated temperature and / or reduced pressure, optionally with an inert gas being passed through the reaction mixture.

The metering in of alkylene oxide (and, if appropriate, of carbon dioxide) can in principle take place in different ways. Dosing can be started from the vacuum or with a pre-selected pre-pressure. The admission pressure is preferably set by introducing carbon dioxide, the pressure (absolute) being 5 mbar to 100 bar, preferably 10 mbar to 50 bar and preferably 20 mbar to 50 bar.

In a preferred embodiment, the amount of alkylene oxide used in the activation in step (β) is 0.1 to 25.0% by weight, preferably 1.0 to 20.0% by weight, particularly preferably 2.0 to 16 , 0% by weight (based on the amount of suspending agent used in step (a)). The alkylene oxide can be added in one step or in portions in several partial amounts. After a portion of the alkylene oxide has been added, the addition of the alkylene oxide is preferably interrupted until the evolution of heat occurs and only then is the next portion of alkylene oxide added.

To step (g): According to the invention, in step (g) alkylene oxide, carbon dioxide and a mixture containing non-activated DMC catalyst and an H-functional starter compound, the bi-functional starter compound being a polyol with a number average molecular weight of 550 to 2000 g / mol, continuously in a Metered into the reactor. The metering of the carbon dioxide, the alkylene oxide, the mixture containing non-activated DMC catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molar mass of 550 to 2000 g / mol, and optionally also further H- functional starter compound can be carried out simultaneously or sequentially (in portions), for example the entire amount of carbon dioxide, the entire amount of mixture containing non-activated DMC catalyst and an H-functional

Starter compound, where the H-functional starter compound is a polyol with a number average molar mass of 550 to 2000 g / mol, the amount of further H-functional starter substances and / or the amount of alkylene oxide dosed in step (g) are added all at once or continuously. The term "continuously" used here can be defined as the mode of adding a reactant in such a way that a concentration of the reactant effective for the copolymerization is maintained, i.e., for example, the metering can be carried out at a constant metering rate, with a varying metering rate or in portions.

It is possible, during the addition of the alkylene oxide, the mixture containing non-activated DMC catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molecular weight of 550 to 2000 g / mol, and / or more H-functional starter substances to gradually or gradually increase or decrease the CCE pressure or to leave it the same. The total pressure is preferably kept constant during the reaction by adding more carbon dioxide. The metering of alkylene oxide, the mixture containing non-activated DMC catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molar mass of 550 to 2000 g / mol, and / or further H-functional starter substance takes place simultaneous or sequential to the carbon dioxide metering. It is possible to meter in the alkylene oxide at a constant metering rate or to increase or decrease the metering rate gradually or stepwise or to add the alkylene oxide in portions. The alkylene oxide is preferably added to the reaction mixture at a constant metering rate. If several alkylene oxides are used

When the polyether carbonate polyols are synthesized, the alkylene oxides can be metered in individually or as a mixture. The metering of the alkylene oxides, the mixture containing non-activated DMC catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molar mass of 550 to 2000 g / mol, or further H-functional starter substances can be carried out simultaneously or sequentially (in portions) via separate dosages (additions) in each case or via one or more dosages, with the alkylene oxide or the further H-functional starter substances individually or as a mixture can be dosed. About the type and / or sequence of metering the further H-functional starter substances, the alkylene oxides, the mixture containing non-activated DMC catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molecular weight of 550 to 2000 g / mol, and / or of the carbon dioxide, it is possible to synthesize random, alternating, block-like or gradient-like polyether carbonate polyols.

In a preferred embodiment, the process is carried out as a semi-batch process and in step (g) the metering of the H-functional starter substance is terminated before the addition of the alkylene oxide.

An excess of carbon dioxide based on the calculated amount of built-in carbon dioxide in the polyether carbonate polyol is preferably used, since an excess of carbon dioxide is advantageous due to the inertia of carbon dioxide. The amount of carbon dioxide can be determined via the total pressure (absolute) (in the context of the invention, the total pressure (absolute) is defined as the sum of the partial pressures of the alkylene oxide and carbon dioxide used) under the respective reaction conditions. The range from 5 to 120 bar, preferably from 10 to 110 bar, particularly preferably from 20 to 100 bar, has proven to be advantageous as the total pressure (absolute) for the copolymerization for the preparation of the polyether carbonate polyols. It is possible to supply the carbon dioxide continuously or discontinuously. This depends on how quickly the alkylene oxides are consumed and whether the product should contain CCE-free polyether blocks. The amount of carbon dioxide (expressed as pressure) can also vary with the addition of the alkylene oxides. CO2 can be dosed into the reactor in a gaseous state or in a liquid state. CO2 can also be added to the reactor as a solid and then, under the selected reaction conditions, change into the gaseous, dissolved, liquid and / or supercritical state. Carbon dioxide can be dosed into the gas phase or the liquid phase.

A preferred embodiment of the method according to the invention is characterized, inter alia, in that the total amount of the H-functional starter substance is added in step (g). This addition can take place at a constant metering rate, with a varying metering rate or in portions.

For the process according to the invention it has also been found that the copolymerization (step (g)) for the preparation of the polyether carbonate polyols is advantageously at 50 to 150 ° C, preferably at 60 to 145 ° C, particularly preferably at 70 to 140 ° C and very particularly preferably is carried out at 90 to 130 ° C. If temperatures are set below 50 ° C., the reaction is generally very slow. At temperatures above 150 ° C., the amount of undesired by-products increases sharply. Steps (a), (β) and (g) can be carried out in the same reactor or in each case separately in different reactors. A particularly preferred type of reactor is the stirred tank.

Polyether carbonate polyols can be produced in a stirred tank, the stirred tank being cooled, depending on the embodiment and mode of operation, via the reactor jacket, internal cooling surfaces and / or cooling surfaces located in a pumping circuit. Both in the semi-batch application, in which the product is removed only after the end of the reaction, and in the continuous application, in which the product is removed continuously, particular attention must be paid to the metering rate of the alkylene oxide. It is to be set in such a way that the alkylene oxides react sufficiently quickly despite the inhibiting effect of the carbon dioxide. The concentration of free alkylene oxides in the reaction mixture during the activation step (step β) is preferably> 0 to 100% by weight, particularly preferably> 0 to 50% by weight, most preferably> 0 to 20% by weight (in each case based on the weight of the reaction mixture). The concentration of free alkylene oxides in the reaction mixture during the reaction (step g) is preferably> 0 to 40% by weight, particularly preferably> 0 to 25% by weight, most preferably> 0 to 15% by weight (in each case based on based on the weight of the reaction mixture).

The polyether carbonate polyols are preferably produced in a continuous process.

The invention therefore also relates to a process in which, in step (g), a mixture containing non-activated DMC catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molar mass of 550 to 2000 g / mol , and alkylene oxide in the presence of carbon dioxide (“copolymerization”) are continuously metered into a reactor and the resulting reaction mixture (containing the reaction product) is continuously removed from the reactor.

The amount of DMC catalyst used is preferably chosen so that the DMC catalyst content in the reaction product resulting in step (g) is 10 to 10,000 ppm, particularly preferably 20 to 5000 ppm and most preferably 50 to 500 ppm.

Steps (a) and (β) are preferably carried out in a first reactor, and the resulting reaction mixture is then transferred to a second reactor for the copolymerization according to step (g). However, it is also possible to carry out steps (a), (β) and (g) in one reactor.

As used herein, "continuous" can be defined as a mode of adding a relevant catalyst or reactant such that a substantially continuous effective concentration of the DMC catalyst or reactant is maintained. The catalyst can be fed in really continuously or in relatively closely spaced increments. Likewise, a continuous addition of starter can be genuinely continuous or take place in increments. It would not deviate from the present method to add a DMC catalyst or reactants incrementally so that the concentration of the added materials for drops to essentially zero some time before the next incremental addition. It is preferred, however, that the DMC catalyst concentration be maintained at substantially the same concentration during the major part of the course of the continuous reaction and that initiator be present during the major part of the copolymerization process. An incremental addition of DMC catalyst and / or reactant that does not materially affect the nature of the product is nonetheless "continuous" in the sense in which the term is used herein. For example, it is feasible to provide a recycle loop in which a portion of the reacting mixture is returned to a previous point in the process, thereby smoothing out discontinuities caused by incremental additions.

The residence time of the reaction mixture in the reactor is preferably 0.5 to 5.0 hours, particularly preferably 1.0 to 4.0 hours, particularly preferably 1.5 to 3.5 hours. The residence time is the mean residence time in an ideally mixed reactor.

To step (d)

According to the optional step (d), the reaction mixture resulting from step (g), which generally contains from 0.05% by weight to 10% by weight alkylene oxide, can be subjected to a post-reaction in the reactor or it can be subjected to a continuous reaction in be transferred to a postreactor for postreaction, the content of free alkylene oxide being reduced by way of the postreaction. In step (d), the content of free alkylene oxide is preferably reduced to less than 0.5% by weight, particularly preferably to less than 0.1% by weight, in the reaction mixture by means of the post-reaction.

If the reaction mixture resulting from step (g) remains in the reactor, the reaction mixture is preferably used for post-reaction for 10 minutes to 24 hours at a temperature of 60 to 140.degree. C., particularly preferably 1 hour to 12 hours at a temperature of 80 to 130.degree held. The reaction mixture is preferably stirred until the content of free alkylene oxide has fallen to less than 0.5% by weight, particularly preferably to less than 0.1% by weight, in the reaction mixture. As a result of the reaction of free alkylene oxide and optionally carbon dioxide, the pressure in the reactor generally falls during the post-reaction in step (d) until a constant value is reached.

A tubular reactor, a loop reactor or a stirred tank, for example, can serve as the postreactor. The pressure in this postreactor is preferably the same as in the reaction apparatus in which reaction step (g) is carried out. However, the pressure in the downstream reactor can also be chosen to be higher or lower. In a further preferred embodiment, the carbon dioxide is completely or partially discharged after reaction step (g) and the downstream reactor is operated at normal pressure or a slight excess pressure. The temperature in the downstream reactor is preferably from 50 to 150.degree. C. and particularly preferably from 80 to 140.degree. A tubular reactor is preferably used as the postreactor, it being possible, for example, to use a single tubular reactor or else a cascade of several tubular reactors arranged in parallel or linearly connected one behind the other. The residence time in the tubular reactor is preferably between 5 minutes and 10 hours, particularly preferably between 10 minutes and 5 hours.

DMC catalyst

DMC catalysts for use in the homopolymerization of alkylene oxides are known in principle from the prior art (see, for example, US-A 3 404 109, US-A 3 829 505, US-A 3 941 849 and US-A 5 158 922) . DMC catalysts which are described, for example, in US Pat. No. 5,470,813, EP-A 700 949, EP-A 743 093, EP-A 761 708, WO 97/40086, WO 98/16310 and WO 00/47649 have a very high activity and enable the production of polyether carbonate polyols with very low catalyst concentrations, so that the catalyst can generally be separated off from the finished product is no longer required. A typical example are the highly active DMC catalysts described in EP-A 700 949 which, in addition to a double metal cyanide compound (e.g. zinc hexacyanocobaltate (III)) and an organic complex ligand (e.g. tert-butanol), also contain a polyether with a number average molecular weight greater than 500 g / mol included.

The DMC catalysts are preferably obtained by

(i) In the first step, an aqueous solution of a metal salt with the aqueous solution of a

Metal cyanide salt in the presence of one or more organic complex ligands, e.g. an ether or alcohol,

(ii) wherein in the second step the solid is obtained from the suspension obtained from (i) by known means

Techniques (such as centrifugation or filtration) are separated,

(iii) where optionally in a third step the isolated solid is washed with an aqueous solution of an organic complex ligand (e.g. by resuspension and subsequent renewed isolation by filtration or centrifugation),

(iv) where the solid obtained, optionally after pulverization, is then dried at temperatures of generally 20-120 ° C. and at pressures of generally 0.1 mbar to normal pressure (1013 mbar), and in the first step or immediately after one or more organic complexing ligands, preferably in excess (based on the double metal cyanide compound) and optionally further complex-forming components are added to the precipitation of the double metal cyanide compound (second step).

The double metal cyanide compounds contained in the DMC catalysts are the reaction products of water-soluble metal salts and water-soluble metal cyanide salts.

For example, an aqueous solution of zinc chloride (preferably in excess based on the metal cyanide salt such as potassium hexacyanocobaltate) and potassium hexacyanocobaltate are mixed and then dimethoxyethane (glyme) or / butanol (preferably in excess, based on zinc hexacyanocobaltate) added to the suspension formed.

Metal salts suitable for preparing the double metal cyanide compounds preferably have the general formula (II),

M (X) "(II) where

M is selected from the metal cations Zn ²⁺ , Fe ²⁺ , Ni ²⁺ , Mn ²⁺ , Co ²⁺ , Sr ² . Sn ²⁺ , Pb ²⁺ and, Cu ²⁺ , M is preferably Zn ²⁺ , Fe ²⁺ , Co ²⁺ or Ni ²⁺ ,

X are one or more (ie different) anions, preferably an anion selected from the group of halides (ie fluoride, chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate, thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and nitrate ; n is 1 when X = sulfate, carbonate or oxalate and n is 2 when X = halide, hydroxide, carboxylate, cyanate, thiocyanate, isocyanate, isothiocyanate or nitrate, or suitable metal salts have the general formula (III),

M _r (X) ₃ (III) where

M is selected from the metal cations Fe ³⁺ , Al ³⁺ , Co ³⁺ and Cr '.

X are one or more (ie different) anions, preferably an anion selected from the group of halides (ie fluoride, chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate, thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and nitrate ; r is 2 when X = sulfate, carbonate or oxalate and r is 1 when X = halide, hydroxide, carboxylate, cyanate, thiocyanate, isocyanate, isothiocyanate or nitrate, or suitable metal salts have the general formula (IV),

M (X) _S (IV) where

M is selected from the metal cations Mo ⁴⁺ , V ⁴⁺ and W ⁴⁺

X are one or more (ie different) anions, preferably an anion selected from the group of halides (ie fluoride, chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate, thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and nitrate ; s is 2 when X = sulfate, carbonate or oxalate and s is 4 if X = halide, hydroxide, carboxylate, cyanate, thiocyanate, isocyanate, isothiocyanate or nitrate, or suitable metal salts have the general formula (V),

M (X), (V) where

M is selected from the metal cations Mo ⁶⁺ and W ⁶⁺

X are one or more (ie different) anions, preferably an anion selected from the group of halides (ie fluoride, chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate, thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and nitrate ; t is 3 when X = sulfate, carbonate or oxalate and t is 6 when X = halide, hydroxide, carboxylate, cyanate, thiocyanate, isocyanate, isothiocyanate or nitrate,

Examples of suitable metal salts are zinc chloride, zinc bromide, zinc iodide, zinc acetate, zinc acetylacetonate, zinc benzoate, zinc nitrate, iron (II) sulfate, iron (II) bromide, iron (II) chloride, iron (III) chloride, cobalt (II) chloride, cobalt ( II) thiocyanate, nickel (II) chloride and nickel (II) nitrate. Mixtures of different metal salts can also be used.

Metal cyanide salts suitable for preparing the double metal cyanide compounds preferably have the general formula (VI)

(Y) a M '(CN) _b (A) c (VI) where

M 'is selected from one or more metal cations from the group consisting of Fe (II), Fe (III), Co (II), Co (III), Cr (II), Cr (III), Mn (II), Mn ( III), Ir (III), Ni (II), Rh (III), Ru (II), V (IV) and V (V), M 'is preferably one or more metal cations from the group consisting of Co (II), Co (III), Fe (II), Fe (III), Cr (III), Ir (III) and Ni (II), Y is selected from one or more metal cations of the group consisting of alkali metal (i.e. Li ⁺ , Na ⁺ , K ⁺ , Rb> nd alkaline earth metal (i.e. Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ^2. Ba ²⁺ ),

A is selected from one or more anions from the group consisting of halides (ie fluoride, chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate, thiocyanate, isocyanate, isothiocyanate, carboxylate, azide, oxalate or nitrate and a, b and c are integer numbers, the values for a, b and c being chosen so that the electrical neutrality of the metal cyanide salt is given; a is preferably 1, 2, 3 or 4; b is preferably 4, 5 or 6; c preferably has the value 0. Examples of suitable metal cyanide salts are sodium hexacyanocobaltate (III), potassium hexacyanocobaltate (III), potassium hexacyanoferrate (II), kabum hexacyanoferrate (III), calcium hexacyanocobaltate (III) and lithium hexacyanocobaltate (III).

Preferred double metal cyanide compounds contained in the DMC catalysts are compounds of the general formula (VII)

M _x [M ' _x , (CN) _y ] _z (VII) wherein M is as defined in formula (II) to (V) and M' is as defined in formula (VI), and x, x ', y and z are whole numbers and chosen so that the electron neutrality of the double metal cyanide compound is given.

Preferably x = 3, x '= 1, y = 6 and z = 2,

M = Zn (II), Fe (II), Co (II) or Ni (II) and M ’= Co (III), Fe (III), Cr (III) or Ir (III).

Examples of suitable double metal cyanide compounds a) are zinc hexacyanocobaltate (III), zinc hexacyanoiridate (III), zinc hexacyanoferrate (III) and cobalt (II) hexacyanocobaltate (III). Further examples of suitable double metal cyanide compounds can be found, for example, in US Pat. No. 5,158,922 (column 8, lines 29-66). Zinc hexacyanocobaltate (III) is particularly preferably used.

The organic complex ligands added during the preparation of the DMC catalysts are for example in US Pat. No. 5,158,922 (see in particular column 6, lines 9 to 65), US Pat. No. 3,404,109, US Pat. No. 3,829,505, US Pat. No. 3,941,849, EP-A 700 949 , EP-A 761 708, JP 4 145 123, US 5 470 813, EP-A 743 093 and WO-A 97/40086). For example, water-soluble, organic compounds with heteroatoms, such as oxygen, nitrogen, phosphorus or sulfur, which can form complexes with the double metal cyanide compound, are used as organic complex ligands. Preferred organic complex ligands are alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles, sulfides and mixtures thereof. Particularly preferred organic complex ligands are aliphatic ethers (such as dimethoxyethane), water-soluble aliphatic alcohols (such as ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, 2-methyl-3-buten-2-ol and 2-methyl-3-butyn-2-ol), compounds which contain both aliphatic or cycloaliphatic ether groups and aliphatic hydroxyl groups (such as, for example, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-tert-butyl ether, tripropylene glycol mono methyl ether and 3-methyl-3-oxetane-methanol). Highly preferred organic complex ligands are selected from one or more compounds from the group consisting 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-oxetane-methanol.

Optionally, one or more complex-forming component (s) from the compound classes of polyethers, polyesters, polycarbonates, polyalkylene glycol sorbitan esters, polyalkylene glycol glycidyl ethers, polyacrylamide, poly (acrylamide-co-acrylic acid), polyacrylic acid, poly (acrylic acid-co- maleic acid), polyacrylonitrile, polyalkyl acrylates, polyalkyl methacrylates, polyvinyl methyl ether, polyvinyl ethyl ether, poly vinyl acetate,

Polyvinyl alcohol, poly-N-vinylpyrrolidone, poly (N-vinylpyrrolidone-co-acrylic acid),

Polyvinyl methyl ketone, poly (4-vinylphenol), poly (acrylic acid-co-styrene), oxazoline polymers, polyalkyleneimines, maleic acid and maleic anhydride copolymers, hydroxyethyl cellulose and polyacetals, or the glycidyl ethers, glycosides, carboxylic acid esters of polyhydric alcohols, bile acids or their salts, esters, Cy clodextrins, phosphorus compounds, a, b-unsaturated carboxylic acid esters or ionic surface or interface-active compounds are used.

In the first step of the preparation of the DMC catalysts, preference is given to the aqueous solutions of the metal salt (e.g. zinc chloride), used in a stoichiometric excess (at least 50 mol%) based on the metal cyanide salt (i.e. at least a molar ratio of metal salt to metal cyanide salt of 2.25 to 1.00) and the metal cyanide salt (e.g. potassium hexacyanocobaltate) reacted in the presence of the organic complex ligand (e.g. tert -butanol), forming a suspension that contains the double metal cyanide compound (e.g. zinc hexacyanocobaltate), water, excess metal salt, and the organic Contains complex ligands.

The organic complex ligand can be present in the aqueous solution of the metal salt and / or the metal cyanide salt, or it is added directly to the suspension obtained after precipitation of the double metal cyanide compound. It has proven advantageous to mix the aqueous solutions of the metal salt and the metal cyanide salt and the organic complex ligand with vigorous stirring. Optionally, the suspension formed in the first step is then treated with a further complex-forming component. The complex-forming component is preferably used in a mixture with water and organic complex ligands. A preferred method for carrying out the first step (i.e. the preparation of the suspension) is carried out using a mixing nozzle, particularly preferably using a jet disperser as described in WO-A 01/39883.

In the second step, the solid (ie the precursor of the catalyst) is isolated from the suspension by known techniques, such as centrifugation or filtration. In a preferred embodiment, the isolated solid is then washed in a third process step with an aqueous solution of the organic complex ligand (for example by resuspension and subsequent renewed isolation by filtration or centrifugation). In this way, for example, water-soluble by-products such as potassium chloride can be removed from the catalyst. The amount of the organic complex ligand in the aqueous washing solution is preferably between 40 and 80% by weight, based on the total solution.

Optionally, in the third step, further complex-forming components, preferably in the range between 0.5 and 5% by weight, based on the total solution, are added to the aqueous washing solution.

It is also advantageous to wash the isolated solid more than once. In a first washing step (iii-1), washing is preferably carried out with an aqueous solution of the organic complex ligand (for example with an aqueous solution of tert-butanol) (for example by resuspension and subsequent renewed isolation by filtration or centrifugation) in order to achieve the Example of removing water-soluble by-products, such as potassium chloride, from the catalyst. The amount of the organic complex ligand (for example tert-butanol) in the aqueous washing solution is particularly preferably between 40 and 80% by weight, based on the total solution of the first washing step. In the further washing steps (iii-2) either the first washing step is repeated once or more times, preferably once to three times, or preferably a non-aqueous solution, such as a mixture or solution of organic complex ligands (for example tert-butanol) and further complex-forming component (preferably in the range between 0.5 and 5% by weight, based on the total amount of the washing solution of step (iii-2)) is used as washing solution and the solid is washed once or several times, preferably once to three times.

The isolated and optionally washed solid is then, optionally after pulverization, dried at temperatures of generally 20-100 ° C. and at pressures of generally 0.1 mbar to normal pressure (1013 mbar).

A preferred process for isolating the DMC catalysts from the suspension by filtration, filter cake washing and drying is described in WO-A 01/80994.

After the process according to the invention for producing the polyether carbonate polyol has been carried out, the resulting reaction mixture generally contains the DMC catalyst in the form of finely dispersed solid particles. It may therefore be desirable to remove the DMC catalyst as completely as possible from the resulting reaction mixture. The separation of the DMC catalyst has the advantage that the resulting Polyether carbonate polyol Industry or certification-relevant limit values, for example with regard to metal content or with regard to emissions otherwise resulting from an activated catalyst remaining in the product, and on the other hand, it is used to recover the DMC catalyst.

The DMC catalyst can be largely or completely removed with the help of various methods: The DMC catalyst can be removed, for example, with the help of membrane filtration (nano-, ultra- or cross-flow filtration), with the help of cake filtration, with the help of pre-coat filtration or by means of Centrifugation to be separated from the polyether carbonate polyol.

A multistage process consisting of at least two steps is preferably used to separate off the DMC catalyst.

For example, in a first step, the reaction mixture to be filtered is divided in a first filtration step into a larger substream (filtrate), in which a large part of the catalyst or all of the catalyst has been separated off, and a smaller residual flow (retentate), which contains the separated catalyst . In a second step, the residual flow is then subjected to dead-end filtration. A further filtrate stream, in which a large part of the catalyst or the entire catalyst has been separated off, and a moist to largely dry catalyst residue are obtained from this.

Alternatively, the catalyst contained in the polyether carbonate polyol can also be subjected to adsorption, agglomeration / coagulation and / or flocculation in a first step, followed by the separation of the solid phase from the polyether carbonate polyol in a second or more subsequent steps. Suitable adsorbents for mechanical-physical and / or chemical adsorption include, among other things, activated or non-activated clays or bleaching earths (sepiolites, montmorillonites, talc, etc.), synthetic silicates, activated carbon, silica / kieselgure and activated silica / kieselgure in typical amounts of 0, 1% by weight to 2% by weight, preferably 0.8% by weight to 1.2% by weight, based on the polyether carbonate polyol at temperatures of 60 ° C. to 140 ° C., preferably 90 ° C. to 110 ° C. and residence times of 20 min to 100 min , preferably 40 min to 80 min, wherein the adsorption step including the mixing in of the adsorbent can be carried out batchwise or continuously. A preferred method for separating this solid phase (consisting, for example, of adsorbent and DMC catalyst) from the polyether carbonate polyol is pre-coat filtration. Here, the filter surface depends on the filtration behavior, which depends on the particle size distribution of the solid phase to be separated, the average specific resistance of the resulting filter cake and the total resistance of the pre-coat layer and filter cake is determined, coated with a permeable / permeable filtration aid (e.g. inorganic: Celite, Perlite; organic: cellulose) with a layer thickness of 20 mm to 250 mm, preferably 100 mm to 200 mm (“Pre -Coat "). The majority of the solid phase (consisting, for example, of adsorbent and DMC catalyst) is separated off on the surface of the pre-coat layer in combination with a Depth filtration of the smaller particles within the pre-coat layer. The temperature of the crude product to be filtered is in the range from 50.degree. C. to 120.degree. C., preferably from 70.degree. C. to 100.degree.

In order to ensure a sufficient flow of product through the pre-coat layer and the cake layer growing on it, the cake layer and a small part of the pre-coat layer can be removed (periodically or continuously) using a scraper or knife and removed from the process. The adjustment of the scraper or knife takes place at minimum feed speeds of approx. 20 pm / min-500 pm / min, preferably in the range 50 pm / min-150 pm / min.

As soon as the pre-coat layer has been largely or completely removed by this process, the filtration is stopped and a new pre-coat layer is applied to the filter surface. The filter aid can be suspended in cyclic propylene carbonate, for example. This pre-coat filtration is typically carried out in vacuum drum filters. In order to achieve technically relevant filtrate throughputs in the range of 0.1 m7 (m ^2, h) to 5 m7 (m ² _* h) in the case of a viscous feed stream, the drum filter can also be used as a pressure drum filter with pressure differences of up to to 6 bar and more between the medium to be filtered and the filtrate side.

In principle, the DMC catalyst can be separated off from the resulting reaction mixture of the process according to the invention both before the removal of volatile constituents (such as, for example, cyclic propylene carbonate) and after the separation of volatile constituents.

Furthermore, the DMC catalyst can be separated off from the resulting reaction mixture of the process according to the invention with or without the further addition of a solvent (in particular cyclic propylene carbonate) in order to lower the viscosity before or during the individual described steps of the catalyst separation.

In addition to the preferred DMC catalysts based on zinc hexacyanocobaltate (Zn3 [Co (CN) e] 2), other metal complex catalysts based on the metals zinc known to those skilled in the art from the prior art for the copolymerization of epoxides and carbon dioxide can also be used for the process according to the invention and / or cobalt can be used. This includes in particular so-called zinc glutarate catalysts (described, for example, in MH Chisholm et al., Macromolecules 2002, 35, 6494), so-called zinc diiminate catalysts (described, for example, in SD Allen, J. Am. Chem. Soc. 2002, 124, 14284), so-called cobalt-salen catalysts (described, for example, in US Pat. No. 7,304,172 B2, US 2012/0165549 A1) and bimetallic zinc complexes with macrocyclic ligands (described, for example, in MR Kember et al., Angew. Chem., Int. Ed., 2009, 48, 931).

Alkylene oxide In general, alkylene oxides (epoxides) having 2-24 carbon atoms can be used for the process according to the invention. The alkylene oxides with 2-24 carbon atoms are, for example, one or more compounds selected from the group consisting of ethylene oxide, propylene oxide, 1-butene oxide, 2,3-butene oxide, 2-methyl-1,2-propene oxide (isobutene oxide), 1-pentene oxide, 2,3-pentene oxide, 2-methyl-1,2-butene oxide, 3-methyl-1,2-butene oxide, 1-hexene oxide, 2,3-hexene oxide, 3,4-hexene oxide, 2-methyl 1,2-pentene oxide, 4-methyl-1,2-pentene oxide, 2-ethyl-1,2-butene oxide, 1-heptene oxide, 1-octene oxide, 1-nonene oxide, 1-decene oxide, 1-undecene oxide, 1-dodecene oxide, 4-methyl-1,2-pentene oxide, butadiene monoxide, isoprene monoxide, cyclopentene oxide, cyclohexene oxide, cycloheptene oxide, cyclooctene oxide, styrene oxide, methyl styrene oxide, pinene oxide, single or multiple epoxidized fats as mono-, di- and triglycerides, epoxidized fatty acids, C1-C24- Esters of epoxidized fatty acids, epichlorohydrin, glycidol and derivatives of glycidol such as, for example, methyl glycidyl ether, ethyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, glyci dyl methacrylate and epoxy-functional alkyoxysilanes such as 3 -Glycidyloxypropyltrimethoxy silane, 3 -Glycidyloxypropyltriethoxy silane, 3 -

Glycidyloxypropyltripropoxysilane, 3-glycidyloxypropyl-methyl-dimethoxysilane, 3-glycidyloxypropyl-ethyldiethoxysilane, 3-glycidyloxypropyltriisopropoxysilane. The alkylene oxides used are preferably ethylene oxide, propylene oxide or a mixture of ethylene oxide and propylene oxide, in particular propylene oxide.

H-functional starter connection

According to the invention, in step (g) a mixture containing non-activated double metal cyanide catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molar mass of 550 to 2000 g / mol, is metered in. The polyol used in the mixture according to the invention has a functionality of at least 2, preferably 2 to 8, particularly preferably 2 to 4 and particularly preferably 2 to 3. The number average molar mass of the polyol is 550 to 2000 g / mol, preferably 600 to 1500 g / mol, particularly preferably 650 to 1250 g / mol and very particularly preferably 700 to 1200 g / mol. The polyol is preferably selected from the group consisting of polyether polyol, polyester polyol, polyester ether polyol, polycarbonate polyol, polyether carbonate polyol and polyacrylate polyol, particularly preferably from the group consisting of polyether polyol and polyether carbonate polyol. The polyol used according to the invention is preferably produced with a DMC catalyst.

In a particularly preferred embodiment, the polyol is at least one compound from the group consisting of polyether polyols with a molecular weight M _n in the range from 550 to 2000 g / mol with a functionality of 2 to 3 and polyether carbonate polyols with a molecular weight M _n in the range from 550 to 2000 g / mol with a functionality of 2 to 3, the polyether polyols and polyether carbonate polyols being very particularly preferably prepared using a DMC catalyst. In a highly preferred embodiment, the polyol is a polyether polyol with a molecular weight M _n in the range from 550 to 2000 g / mol with a functionality of 2 to 3.

The polyol with a number average molar mass of 550 to 2000 g / mol can contain one or more of the compounds mentioned.

It is possible that the polyol contains a proportion of activated DMC catalyst. The amount of activated DMC catalyst in the polyol used is preferably 500 ppm and less, preferably 250 ppm and less, particularly preferably 125 ppm and less, based in each case on the amount of polyol used in the mixture containing non-activated double metal cyanide catalyst and an H-functional starter compound, the bi-functional starter compound being a polyol with a number average molar mass of 550 to 2000 g / mol.

In a preferred embodiment, the proportion of non-activated DMC catalyst in the mixture comprising non-activated DMC catalyst and polyol with a number average molar mass of 550 to 2000 g / mol is 50 to 97% by weight, particularly preferably 60 to 90 % By weight, very particularly preferably 70 to 80% by weight, in each case based on the sum of the mass of the non-activated and activated DMC catalyst.

In addition to the polyol with a number average molar mass of 550 to 2000 g / mol, further H-functional starter substances can be used in the process according to the invention.

Suitable further H-functional starter substances (“starters”) can be compounds with H atoms active for the alkoxylation, which have a molar mass of 18 to 4500 g / mol, preferably from 62 to 500 g / mol and particularly preferably from 62 to 182 g / mol.

Groups with active H atoms which are active for the alkoxylation are, for example, -OH, -NH2 (primary amines), -NH- (secondary amines), -SH and -CO2H, -OH and -NH2 are preferred, -OH is particularly preferred. The H-functional starter compound is, for example, one or more compounds selected from the group consisting of monohydric or polyhydric alcohols, polyhydric amines, polyhydric thiols, amino alcohols, thioalcohols, hydroxyesters, polyether polyols, polyester polyols, polyester ether polyols, polyether carbonate polyols, polycarbonate polyols, polycarbonates, polyethylene imines, polyether amines , Polytetrahydrofuran (e.g. PolyTHF® from BASF), polytetrahydrofuran amines, polyether thiols, polyacrylate polyols, castor oil, the mono- or diglyceride of ricinoleic acid, monoglycerides of fatty acids, chemically modified mono-, di- and / or triglycerides of fatty acids, and C1- C24 alkyl fatty acid esters containing on average at least 2 OH groups per molecule are used. For example, the C1-C24 alkyl fatty acid esters, which contain on average at least 2 OH groups per molecule, are commercial products such as Lupranol Balance® (BASF AG), Merginol® types (Hobum Oleochemicals GmbH), Sovermol® types (from Cognis Deutschland GmbH & Co. KG) and Soyol®TM types (from US SC Co.).

Alcohols, amines, thiols and carboxylic acids can be used as mono-H-functional starter compounds. The following can be used as monofunctional alcohols: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 3-buten-1-ol, 3-butyn-1-ol, 2-methyl - 3-buten-2-ol, 2-methyl-3-butyn-2-ol, propagyl alcohol, 2-methyl-2-propanol, 1-tert-butoxy-2-propanol, 1-pentanol, 2-pentanol, 3 -Pentanol, 1-hexanol, 2-hexanol, 3-hexanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 3-octanol, 4-octanol, phenol, 2-hydroxybiphenyl, 3 - Hydroxybiphenyl, 4-hydroxybiphenyl, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine. Possible monofunctional amines are: butylamine, tert-butylamine, pentylamine, hexylamine, aniline, aziridine, pyrrolidine, piperidine, morpholine. The following can be used as monofunctional thiols: ethanethiol, 1-propanethiol, 2-propanethiol, 1-butanethiol, 3-methyl-1-butanethiol, 2-butene-1-thiol, thiophenol. The following monofunctional carboxylic acids may be mentioned: formic acid, acetic acid, propionic acid, butyric acid, fatty acids such as stearic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, acrylic acid.

Polyhydric alcohols suitable as H-functional starter compounds are, for example, dihydric alcohols (such as, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-butenediol, 1,4-butynediol, neopentyl glycol, 1 , 5-pentanediol, methylpentanediols (such as 3-methyl-1,5-pentanediol), 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, bis (hydroxymethyl) - cyclohexanes (such as, for example, 1,4-bis (hydroxymethyl) cyclohexane), triethylene glycol, tetraethylene glycol, polyethylene glycols, dipropylene glycol, tripropylene glycol, polypropylene glycols, dibutylene glycol and polybutylene glycols); trihydric alcohols (such as trimethylolpropane, glycerin, trishydroxyethyl isocyanurate, castor oil); tetravalent alcohols (such as pentaerythritol); Polyalcohols (such as, for example, sorbitol, hexitol, sucrose, starch, starch hydrolysates, cellulose, cellulose hydrolysates, hydroxy-functionalized fats and oils, in particular castor oil), as well as all modification products of these aforementioned alcohols with different amounts of e-caprolactone.

The H-functional starter compounds can also be selected from the class of polyether polyols which have a molecular weight Mn in the range from 18 to 4500 g / mol and a functionality of 1-8, preferably 2-3. Preference is given to polyether polyols which are built up from repeating ethylene oxide and propylene oxide units, preferably with a proportion of 35 to 100% propylene oxide units, particularly preferably with a proportion of 50 to 100% propylene oxide units. These can be random copolymers, gradient copolymers, alternating or block copolymers of ethylene oxide and propylene oxide. The H-functional starter compounds can also be selected from the substance class of polyester polyols. At least difunctional polyesters are used as polyester polyols. Polyester polyols preferably consist of alternating acid and alcohol units. As acid components, for. B. succinic acid, maleic acid, maleic anhydride, adipic acid, phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride or mixtures of the acids and / or anhydrides mentioned. As alcohol components, for. B. ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-bis (hydroxymethyl) cyclohexane, diethylene glycol, Dipropylene glycol, trimethylolpropane, glycerol, pentaerythritol or mixtures of the alcohols mentioned are used. If dihydric or polyhydric polyether polyols are used as the alcohol component, polyester ether polyols are obtained which can also serve as starter compounds for the preparation of the polyether carbonate polyols.

Furthermore, polycarbonate diols can be used as H-functional starter compounds, which are prepared, for example, by reacting phosgene, dimethyl carbonate, diethyl carbonate or diphenyl carbonate and difunctional alcohols or polyester polyols or polyether polyols. Examples of polycarbonates can be found e.g. B. in EP-A 1359177.

In a further embodiment of the invention, polyether carbonate polyols can be used as functional starter compounds. These polyether carbonate polyols used as H-functional starter compounds are prepared beforehand in a separate reaction step for this purpose.

The H-functional starter compounds generally have a functionality (i.e. number of H atoms active for the polymerization per molecule) of 1 to 8, preferably 2 or 3. The H-functional starter compounds are used either individually or as a mixture of at least two H-functional starter compounds.

The H-functional starter compounds are particularly preferably one or more compounds selected from the group consisting 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, 1,8-octanediol, diethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol and polyether polyols with a molecular weight Mn in the range from 150 to 4500 g / mol and a functionality of 2 to 3. The polyether carbonate polyols are produced by the catalytic addition of carbon dioxide and alkylene oxides to H-functional starter compounds. In the context of the invention, ... H-functional is understood to mean the number of H atoms active for the alkoxylation per molecule of the starter compound.

Component K

Compounds suitable as component K are characterized in that they contain at least one phosphorus-oxygen-hydrogen group. Component K is preferably selected from at least one compound from the group consisting of phosphoric acid,

Mono- and dialkyl esters of phosphoric acid,

Mono- and diaryl esters of phosphoric acid,

Mono- and dialkaryl esters of phosphoric acid,

(NH ₄ ) ₂ HP0 ₄ ,

Phosphonic acid,

Monoalkyl ester of phosphonic acid,

Monoaryl ester of phosphonic acid,

Monoalkaryl ester of phosphonic acid,

Phosphorous acid,

Mono- and dialkyl esters of phosphorous acid,

Mono- and diaryl esters of phosphorous acid,

Mono- and dialkaryl esters of phosphorous acid and phosphinic acid.

The mono- or dialkyl esters of phosphoric acid are preferably the mono- or dialkyl esters of ortho-phosphoric acid, mono, di- or trialkyl esters of pyrophosphoric acid and mono-, di-, tri-, tetra- or polyalkyl esters of polyphosphoric acid, particularly preferably the respective esters with Alcohols with 1 to 30 carbon atoms. The mono- or diaryl esters of phosphoric acid are preferably the mono- or diaryl esters of ortho-phosphoric acid, mono-, di- or triaryl esters of pyrophosphoric acid and mono-, di-, tri-, tetra- or polyaryl esters of polyphosphoric acid, particularly preferably the respective esters with alcohols with 6 or 10 carbon atoms. The mono- or dialkaryl esters of phosphoric acid are preferably the mono- or dialkaryl esters of orthophosphoric acid, mono-, di- or trialkaryl esters of pyrophosphoric acid and mono-, di-, tri-, tetra or polyalkaryl esters of polyphosphoric acid, particularly preferably the respective esters with alcohols with 7 to 30 carbon atoms. The following compounds, for example, are suitable as component K: phosphoric acid diethyl ester, phosphoric acid monoethyl ester,

Phosphoric acid dipropyl ester, phosphoric acid monopropyl ester, phosphoric acid dibutyl ester, phosphoric acid monobutyl ester, phosphoric acid diphenyl ester, phosphoric acid dicresyl ester, fructose-1,6-bisphosphate, glucose-1-phosphate, phosphoric acid-bis- (4-nitrophenyl) -ester, phosphoric acid- dibenzyl ester, phosphoric acid diethyl-3-butenyl ester, phosphoric acid dihexadecyl ester,

Phosphoric acid diphenyl ester and phosphoric acid 2-hydroxyethyl methacrylate ester.

The respective esters with alcohols having 1 to 30 carbon atoms are preferably used as monoalkyl esters of phosphonic acid. The respective esters with alcohols having 6 or 10 carbon atoms are preferably used as monoaryl esters of phosphonic acid. The respective esters with alcohols having 7 to 30 carbon atoms are preferably used as monoalkaryl esters of phosphonic acid.

The esters with alcohols having 1 to 30 carbon atoms are preferably used as mono- and dialkyl esters of phosphorous acid. This includes, for example, phenylphosphonic acid, butylphosphonic acid, dodecylphosphonic acid, ethylhexylphosphonic acid, octylphosphonic acid, ethylphosphonic acid, methylphosphonic acid and octadecylphosphonic acid. The respective esters with alcohols having 6 or 10 carbon atoms are preferably used as mono- and diaryl esters of phosphorous acid. The respective esters with alcohols having 7 to 30 carbon atoms are preferably used as mono- and dialkaryl esters of phosphorous acid.

Component K is particularly preferably selected from at least one compound from the group consisting of phosphoric acid, phosphonic acid and phosphinic acid. Component K is most preferably phosphoric acid.

The alcohols with 1 to 30 carbon atoms mentioned in the description of component K are, for example, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, Octadecanol, nonadecanol, methoxymethanol, ethoxymethanol, propoxymethanol, butoxymethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol, phenol, ethyl hydroxyacetate, propyl propyl ester, ethyl hydroxypropionate, propanediol propionate, 1,2-propanediol, 1,2-propanediol, 2,3-trihydroxypropane, 1,1,1-trimethylolpropane or pentaerythritol.

In addition, compounds of phosphorus which can form one or more phosphorus-oxygen-hydrogen groups through reaction with OH-functional compounds (such as, for example, water) are suitable as component K. For example, such compounds of phosphorus are phosphorus (V) sulfide, phosphorus tribromide, phosphorus trichloride and phosphorus triiodide.

Any mixtures of the aforementioned compounds can also be used as component K. Component K can also be used as a mixture with suspending agent or as a mixture with phosphoric acid trialkyl ester (in particular phosphoric acid triethyl ester).

In a preferred embodiment, component K is selected from at least one compound from the group consisting of phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, phosphonous acid, phosphinous acid, phosphine oxides and salts, esters, halides and amides of phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, phosphonous acid , Phosphinous acid, phosphorus (V) sulfide, phosphorus tribromide, phosphorus trichloride and phosphorus triiodide. Component K can be metered in in any step of the process, component K preferably being metered in such that the reaction product resulting from step (g) is in an amount of 5 to 2000 ppm, particularly preferably 10 to 1000 ppm, particularly preferably 30 to 500 Contains ppm. It is advantageous to meter in component K in step (g); component K is particularly preferably metered in mixed with an H-functional starter compound. It is also advantageous to add component K to the reaction mixture in the postreactor in step (d). It is also advantageous to add component K to the resulting reaction mixture only after the post-reaction (step (d)).

In a preferred embodiment, the polyol in the mixture in step (g) contains a component K in a proportion of 5 to 2000 ppm, with component K being selected from at least one compound from the group consisting of phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, Phosphonous acid, phosphinous acid, phosphine oxides and salts, esters, halides and amides of phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, phosphonous acid, phosphinous acid, phosphorus (V) sulfide, phosphorus tribromide, phosphorus trichloride and phosphorus triiodide.

In one possible embodiment of the invention, component K is added during the post-reaction (step (d)) in an amount of 5 ppm to 1000 ppm, particularly preferably 10 ppm to 500 ppm, most preferably 20 ppm to 200 ppm, based in each case on that in step (g) reaction mixture obtained, added. Component K is particularly preferred during the post-reaction at a content of free alkylene oxide of 0.1% by weight to 10% by weight, most preferably from 1% by weight to 10% by weight alkylene oxide and particularly preferably from 5 wt% to 10 wt% added. When carrying out the process according to the invention using a tubular reactor for the post-reaction in step (d), component K is particularly preferably metered in in the second half of the distance which the reaction mixture travels in the tubular reactor.

The polyether carbonate polyols obtained according to the invention have, for example, a functionality of at least 2, preferably from 2 to 8, particularly preferably from 2 to 6 and very particularly preferably from 2 to 4. The molecular weight is preferably 800 to 10,000 g / mol and particularly preferably 1200 to 6000 g / mol.

The polyether carbonate polyols obtainable by the process according to the invention have a low content of by-products and can be processed without problems, in particular by reaction with di- and / or polyisocyanates to form polyurethanes, in particular flexible polyurethane foams. For polyurethane applications, preference is given to using polyether carbonate polyols which are based on an H-functional starter compound which has a functionality of at least two. Furthermore, the polyether carbonate polyols obtainable by the process according to the invention can be used in applications such as washing and cleaning agent formulations, drilling fluids, fuel additives, ionic and non-ionic surfactants, lubricants, process chemicals for paper or textile production or cosmetic formulations.

The person skilled in the art is aware that, depending on the respective field of application, the polyether carbonate polyols to be used must meet certain material properties such as molecular weight, viscosity, functionality and / or hydroxyl number.

Examples

The invention is explained in more detail by means of the following examples, without, however, being restricted thereto.

The DMC catalyst used in the examples was prepared according to Example 6 of WO-A 01/80994.

The pressure information relates to the absolute pressure.

GPC:

The number average M _n and the weight _{average M w of} the molecular weight and the polydispersity (M _w / M _n ) of the products were determined by means of gel permeation chromatography (GPC). The procedure was in accordance with DIN 55672-1 (March 2016): "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, 8x300 mm, 5 pm; RID detector). Polystyrene samples of known molar mass were used for calibration.

CC content in the polyether carbonate polyol:

The proportion of built-in CO2 in the resulting polyether carbonate polyol and the ratio of propylene carbonate to polyether carbonate polyol were determined by means of 'H-NMR (Bruker, DPX 400, 400 MHz; pulse program zg30, waiting time dl: 10s, 64 scans). The sample was each dissolved in deuterated chloroform. The relevant resonances in 'H-NMR (based on TMS = 0 ppm) are as follows:

Cyclic carbonate (which was formed as a by-product) with resonance at 4.5 ppm, carbonate, resulting from carbon dioxide built into the polyether carbonate polyol with resonances at 5.1 to 4.8 ppm, unreacted PO with resonance at 2.4 ppm, polyether polyol ( ie without built-in carbon dioxide) with resonances at 1.2 to 1.0 ppm, the 1.8 octanediol built in as a starter molecule (if present) with a resonance at 1.6 to 1.52 ppm.

The molar fraction of the carbonate built into the polymer in the reaction mixture is calculated according to formula (VIII) as follows, the following abbreviations being used:

F (4,5) = area of the resonance at 4.5 ppm for cyclic carbonate (corresponds to an H atom)

F (5, 1-4.8) = area of the resonance at 5, 1-4.8 ppm for polyether carbonate polyol and one H atom for cyclic carbonate.

F (2.4) = area of the resonance at 2.4 ppm for free, unreacted PO F (1.2-1.0) = area of the resonance at 1.2-1.0 ppm for polyether polyol

F (1.6-1.52) = area of the resonance at 1.6-1.52 ppm for 1.8 octanediol (starter), if available Taking into account the relative intensities, the following formula (VIII) was used to convert the polymer-bound carbonate ("linear carbonate" LC) in the reaction mixture into mol%:

_ F (5, l - 4.8) - F (4.5) _

LC * 100 (VIII)

F (5, l - 4.8) + F (2.4) + 0.33 * F (l, 2 - 1.0) + 0.25 * F (l, 6 - 1.52)

The weight fraction (in% by weight) of polymer-bound carbonate (LC ') in the reaction mixture was calculated according to formula (IX),

where the value for N ("denominator" N) is calculated according to formula (X):

N = [F (5, l-4.8) -F (4.5)] * 102 + F (4.5) * 102 + F (2.4) * 58 + 0.33 * F (l, 2-l, 0) * 58 + 0.25 * F (l, 6-l, 52) * 146 (X)

The factor 102 results from the sum of the molar masses of CO2 (molar mass 44 g / mol) and that of propylene oxide (molar mass 58 g / mol), the factor 58 results from the molar mass of propylene oxide and the factor 146 results from the molar mass of the starter used 1,8-octanediol (if available).

The weight fraction (in% by weight) of cyclic carbonate (CC ') in the reaction mixture was calculated according to formula (XI), (4.5) * 102

CC * 100% (XI)

N where the value for N is calculated according to formula (X).

In order from the values of the composition of the reaction mixture the composition based on the polymer content (consisting of polyether polyol, which was built up from starter and propylene oxide during the _{activation steps taking place under CO 2} -free conditions, and polyether carbonate polyol, built up from starter, propylene oxide and carbon dioxide during To calculate the activation steps taking place in the presence of CO2 and during the copolymerization), the non-polymer components of the reaction mixture (ie cyclic propylene carbonate and any unreacted propylene oxide present) were eliminated by calculation. The weight fraction of the carbonate repeating units in the polyether carbonate polyol was in a weight fraction of carbon dioxide converted using the factor F = 44 / (44 + 58). The specification of the CCE content in the polyether carbonate polyol is standardized to the proportion of the polyether carbonate polyol molecule that was formed during the copolymerization and, if applicable, the activation steps in the presence of CO2 (i.e. the proportion of the polyether carbonate polyol molecule that was formed from the starter (1.8 - Octanediol, if present) and resulting from the reaction of the starter with epoxide, which was added under CCE-free conditions, was not taken into account).

Example 1: Copolymerization of propylene oxide and CO2 using a non-activated DMC catalyst Production of catalyst-polyol mixture 1

In a first container 6.108 g DMC catalyst (not activated) and 170 ppm H3PO4 (85%) were mixed into 10 kg poly (oxypropylene) polyol with a number average molecular weight of 683 g / mol and a functionality of 2.8. The poly (oxypropylene) polyol already contained 65 ppm activated DMC catalyst. Step (a)

A suspension of 0.83 g of DMC catalyst (not activated) and 5 kg of polyether carbonate polyol with a number average molecular weight of 2914 g / mol, a functionality of 2.8 and a CCE content of 14.6% submitted. Step (ß)

The reactor was adjusted to a pressure of 30 bar and correspondingly tempered to 120 ° C. by adding CCE. 0.25 kg of propylene oxide (PO) were metered into the reactor at 120 ° C. with stirring over the course of 2 minutes. The start of the reaction made itself felt by a temperature peak (“hotspot”). A second addition of 0.25 kg of propylene oxide took place over the course of 2 minutes, and the start of the reaction was again noticeable by a temperature peak.

Step (y)

After activation had taken place, the reactor contents were heated to 120.degree. Propylene oxide was then metered into the reactor at 7.7 kg / h, the catalyst-polyol mixture 1 at 2.7 kg / h and carbon dioxide at the same time, so that a residence time of 2.5 h and a total pressure resulted in steady-state continuous operation of the stirred reactor of 30 bar. The concentration of free propylene oxide (measured in the reactor by means of an MIR probe) in the steady, continuous state was 1.1% by weight, and the reaction temperature was 107 ° C. The catalyst concentration in the reactor was 100 ppm. Step (S) The reaction mixture was then conveyed out of the pressure reactor via a Rohmachreactor (reaction volume 2 liters) heated to 120.degree. The buffer tank before the cyclic propylene carbonate was separated off was operated at 120 ° C. and with an average residence time of 4 hours.

Finally, to separate off the cyclic propylene carbonate, the product was subjected to a two-stage thermal work-up, namely in a first stage by means of a falling film evaporator followed in a second stage by a stripping column operated in nitrogen countercurrent.

The falling film evaporator was operated at a temperature of 169 ° C. and a pressure of 17 mbar (absolute).

The nitrogen stripping column was operated at a temperature of 160 ° C., a pressure of 80 mbar (absolute) and a nitrogen flow rate of 0.6 kg of N2 / kg of product.

Example 2: Copolymerization of propylene oxide and CO2 using a non-activated DMC catalyst

The process in Example 2 was carried out analogously to Example 1, with a residence time of 1.7 hours resulting in steady-state continuous operation of the stirred reactor in step (g).

Example 3: Copolymerization of propylene oxide and CO2 using a non-activated DMC catalyst

The process in Example 2 was carried out analogously to Example 1, with a residence time of 1.4 h resulting in steady, continuous operation of the stirred reactor in step (g).

Example 4 (comparison): Copolymerization of propylene oxide and CO2 using an activated DMC catalyst

Production of catalyst-polyol mixture 2

In a first reactor, 4.476 g of DMC catalyst (not activated) were mixed into 10 kg of poly (oxypropylene) polyol with a number average molar mass of 716 g / mol and a functionality of 2.8. The poly (oxypropylene) polyol was heated to 100 ° C. and stripped for 60 min with addition of N2 at 10 mbara. The container contents were then heated to 130 ° C. and a pressure of 30 bar was set by adding CCL. The catalyst was activated by adding 2.9 kg of propylene oxide, which was noticeable at a temperature peak. This activation step was repeated twice, each time the start of the reaction being noticeable by a temperature peak. _{170 ppm H 3} PO ₄ (85%) were added to the catalyst / polyol mixture 2.

Step (a)

A suspension of 0.5 g of DMC catalyst (not activated) and was fed into a pressure reactor which had been rendered inert with nitrogen and had a gas metering device (gas inlet pipe) and product discharge pipe 5 kg of polyether carbonate polyol with a number average molar mass of 2914 g / mol, a functionality of 2.8 and a CCE content of 14.6%.

Step (ß)

The reactor was adjusted to a pressure of 30 bar and correspondingly tempered to 120 ° C. by adding CO2. At 120 ° C., with stirring, 0.225 kg of propylene oxide (PO) were metered into the reactor over the course of 2 minutes. The start of the reaction made itself felt by a temperature peak (“hotspot”). A second addition of 0.225 kg of propylene oxide (PO) takes place within 2 minutes.The start of the reaction was again noticeable by a temperature peak (“hotspot”).

Step (y)

After activation had taken place, the reactor contents were heated to 120.degree. Propylene oxide was then metered into the reactor at 6.6 kg / h, the catalyst-polyol mixture 2 at 3.45 kg / h and carbon dioxide at the same time, so that in steady-state continuous operation of the stirred reactor, a residence time of 2.9 h and a pressure of 30 bar. The catalyst concentration in the reactor was 100 ppm. The temperature should be gradually reduced to a target value of 112 ° C, but after 6 h when it was lowered to 114 ° C, a free propylene oxide concentration of over 5% (measured in the reactor using the MIR probe) had built up, so that due to the high temperature - and pressure fluctuations, stable process management was no longer possible. Then, after the free propylene oxide concentration had slowly decreased, the experiment was restarted at 120 ° C. and the temperature was slowly lowered to 117 ° C. and the system was continued at this temperature. The concentration of free propylene oxide (measured in the reactor by means of an MIR probe) in the steady, continuous state was 3.8% by weight. An increase in the throughputs to shorten the residence times in the main reactor was not possible for reasons of process stability. The reaction mixture was withdrawn continuously from the reactor via the product discharge pipe.

Step (d)

To complete the reaction, the reaction mixture was conveyed through a tubular reactor heated to 120.degree. The buffer tank before the separation was operated at 120 ° C. and a residence time of 4 hours on average. The cyclic propylene carbonate was separated off from the polyether carbonate polyol in a manner analogous to the process in Examples 1 to 3.

Example 5 (comparison): Copolymerization of propylene oxide and CO2 using a short-chain starter, production of catalyst-polyol mixture 3 In a first reactor, 26.5 g of DMC catalyst (not activated) were mixed into 5 kg of a mixture of glycerol (4.25 kg) and propylene glycol (0.75% by weight) corresponding to a mixture functionality of 2.8. 170 ppm H3PO4 (85%) were added to the catalyst-polyol mixture 3.

Step (a)

A suspension of 1 g of DMC catalyst (not activated) and 4.7 kg of propylene carbonate were placed in a pressure reactor which had been rendered inert with nitrogen and had a gas metering device (gas inlet pipe) and product discharge pipe.

Step (ß)

The reactor was adjusted to a pressure of 30 bar and correspondingly tempered to 120 ° C. by adding CO2. At 120 ° C., with stirring, 0.225 kg of propylene oxide (PO) were metered into the reactor over the course of 2 minutes. The start of the reaction made itself felt by a temperature peak (“hotspot”). A second addition of 0.225 kg of propylene oxide (PO) takes place within 2 minutes.The start of the reaction was again noticeable by a temperature peak (“hotspot”).

Step (y)

After activation had taken place, the reactor contents were heated to 120.degree. Propylene oxide was then metered into the reactor at 7.4 kg / h, the catalyst-polyol mixture 3 at 0.26 kg / h and carbon dioxide at the same time, so that a residence time of 3.8 hours and a pressure of 30 hours were achieved in steady-state, continuous operation of the stirred reactor cash yielded. The catalyst concentration in the reactor was 150 ppm. The temperature was gradually lowered to a target value of 107 ° C. The concentration of free propylene oxide (measured in the reactor by means of an MIR probe) in the steady, continuous state was 2.4% by weight. The reaction mixture was withdrawn continuously from the reactor via the product discharge pipe.

Step (d)

To complete the reaction, the reaction mixture was conveyed through a tubular reactor heated to 120.degree. The buffer tank before the separation was operated at 120 ° C. and a residence time of 4 hours on average. The cyclic propylene carbonate was separated off from the polyether carbonate polyol in a manner analogous to the process in Examples 1 to 3. Table 1:

* Comparative examples

** Ratio of cyclic carbonate / linear carbonate

Claims

Claims

1. A process for the preparation of polyether carbonate polyols, comprising the step of reacting alkylene oxide with carbon dioxide in the presence of an H-functional starter compound and double metal cyanide catalyst, characterized in that

(a) a partial amount of H-functional starter substance and / or suspending agent which does not contain any H-functional groups is placed in a reactor together with DMC catalyst,

(ß) a partial amount of alkylene oxide is added to the mixture from step (a) at temperatures of 90 to 150 ° C, and the addition of the alkylene oxide is then interrupted,

(g) Alkylene oxide, carbon dioxide and a mixture containing non-activated double metal cyanide catalyst and an H-functional starter compound, the H-functional starter compound being a polyol with a number average molar mass according to DIN 55672-1 of 550 to 2000 g / mol, continuously is added to the mixture resulting from (ß).

2. The method according to claim 1, characterized in that the reaction product resulting from step (g) is continuously withdrawn from the reactor.

3. The method according to claim 2, characterized in that the mean residence time of the reaction mixture in step (g) is 0.5 to 5.0 hours.

Process according to claim 2, characterized in that the mean residence time of the reaction mixture in step (g) is 1.5 to 5.0 hours.

5. The method according to any one of claims 1 to 4, characterized in that the mixture containing non-activated double metal cyanide catalyst and an H-functional starter compound contains 500 ppm or less of an activated double metal cyanide catalyst, based on the H-functional starter compound.

6 The method according to any one of claims 1 to 5, characterized in that the proportion of non-activated DMC catalyst in the mixture containing non-activated DMC catalyst and an H-functional starter compound is 50 to 97 wt .-%, based on the sum of the mass of the non-activated and activated DMC catalyst in the mixture.

7. The method according to any one of claims 1 to 6, characterized in that one component

K is added so that the reaction product resulting from step (g) contains a component K in a proportion of 5 to 2000 ppm.

8. The method according to claim 7, characterized in that component K is selected from at least one compound from the group consisting of phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, phosphonous acid, phosphinous acid, phosphine oxides and Salts, esters, halides and amides of phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, phosphonous acid, phosphinous acid, phosphorus (V) sulfide, phosphorus tribromide, phosphorus trichloride and phosphorus triiodide.

9. The method according to any one of claims 1 to 7, characterized in that the polyol in the mixture in step (g) contains a component K in a proportion of 5 to 2000 ppm, component K being selected from at least one compound of the group consisting of phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, phosphonous acid, phosphinous acid, phosphine oxides and salts, esters, halides and amides of phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, phosphonous acid, phosphinous acid, phosphorus (V) sulfide, phosphorus tribromide, phosphorus trichloride and Phosphorus triiodide.

10. The method according to any one of claims 1 to 9, characterized in that the polyol in the mixture in step (g) has a number average molar mass according to DIN 55672-1 of 600 to 1500 g / mol.

11. The method according to any one of claims 1 to 10, characterized in that the polyol in the mixture in step (g) is selected from at least one compound from the group consisting of polyether polyol, polyester polyol, polyester ether polyol, polycarbonate polyol, polyether carbonate polyol and polyacrylate polyol.

12. The method according to any one of claims 1 to 9, characterized in that the H-functional starter compound in the mixture containing non-activated double metal cyanide catalyst and an H-functional starter compound in step (g) is selected from at least one compound from the group consisting of from polyether polyols with a molecular weight M _n according to DIN 55672-1 in the range from 550 to 2000 g / mol with a functionality of 2 to 3 and polyether carbonate polyols with a molecular weight M _n in the range from 550 to 2000 g / mol with a functionality of 2 to 3.

13. The method according to any one of claims 1 to 12, characterized in that the

Double metal cyanide catalyst is present in step (g) in a proportion of 10 to 10,000 ppm, based on the total reaction mixture.

14. The method according to any one of claims 1 to 13, characterized in that the alkylene oxide used is ethylene oxide, propylene oxide or a mixture of propylene oxide and ethylene oxide.

15. The method according to any one of claims 1 to 14, characterized in that the double metal cyanide catalyst used is at least one compound selected from the group consisting of zinc hexacyanocobaltate (III), zinc hexacyanoiridate (III), zinc hexacyanoferrate (III) and cobalt (II) hexacyanocobaltate ( III) contains.