DD237438A3 - PROCESS FOR PREPARING COPOLYETHERALCOOHOLES - Google Patents

Abstract

The invention relates to a process for the preparation of substantially molecularly uniform, liquid at room temperature Copolyetheralkoholen, which can be used for low-temperature-resistant polyurethane components, thermoplastic polyurethanes special properties as Linearisierungsmittel for polyurethanes and as nonionic grenzflaechenaktive substances and lubricants or lubricants. Such Copolyetheralkohole with an average molecular weight between 500 and 20,000 and a hydroxyl functionality of 1 to 6 are obtained by an alkaline-doped polyhydroxyl compound as so-called starting substance at temperatures between 20 and 150C and at pressures of 0.1 to 2.5 MPa erfindaess initially with A mixture of at least two alkylene oxides in the weight ratio 99: 1 to 1: 1 is reacted and then the reaction product formed is reacted in a further reaction step with a mixture of at least two alkylene oxides in the weight ratio of 1: 1 to 1:99.

Description

Title of the invention

Process for the preparation of copolyether alcohols Field of application of the invention

The invention relates to a process for preparing substantially molecularly uniform, liquid at room temperature Copolyetheralkohole of a starter or initiator mixture and several Alkylenoxidan used for low temperature resistant polyurethane components, thermoplastic polyurethanes special properties, as Linearisierungsmittel in polyurethanes, as nonionic surfactants and lubricants can be »

Characteristic of the known technical solutions

The preparation of polyether alcohols by anionic polymerization of alkylene oxides to one or more suitable starter compounds having active hydrogen atoms has been known for a long time and is widely used industrially.

For the preparation of starting components for polyurethanes and of surfactants, in particular two methods have found wide application, namely the homopolymerization of an alkylene oxide to a starter and the copolymerization of several alkylene oxides to suitable initiators and again, in particular, the block copolymerization. Such products and processes are described in N · Schönfeldt, interface

η i i AO Π > i, f Λ

active ethylene oxide adducts, Stuttgart, FRG, 1976.

It is known that when using propylene oxide for the preparation of relatively high molecular weight polyether alcohols by an isomerization of the propylene oxide allyl alcohol or cis-propenyl alcohol is formed. Such alcohols can act as starters for monofunctional polyether alcohols and thus lower the functionality of higher functional polyether alcohols and lead to a high content of double bonds (expressed by the Dodzahl). The causes and effects are z. As described by H. Becker, G. Wagner, A. Stolarzewicz, Acta Polymer. 33_ (1), 34 (1982).

To circumvent these disadvantages, a whole series of methods has been proposed. Of importance for industrial use is the copolymerization of propylene oxide with a certain proportion of ethylene oxide. This method is z. In U.S. Patent 3,461,086, according to which 8 to 30% by weight of ethylene oxide is added. It has been shown to be 3. Cellular Plast. 1. (1), 121 (1965) 7 that even such products at higher average molecular weights have an increasing Dodzahl, even with further improved methods, as described in DE-OS 20 35 134.

In a blockwise arrangement of two monomers, for example ethylene oxide and propylene oxide, a reduction in the unsaturation by dilution with ethylene oxide is therefore observed at best. Another proposed solution is the addition of at least 25 % of the total amount of ethylene oxide to propylene oxide (DD-WP 151 569). This makes it possible to reduce the amount of rearrangement to about half of the usual levels. Another known technical teaching assumes "copolymerize only 1 to 5 wt .-% of ethylene oxide with propylene oxide (DD-WP 143 083) · These two methods are based in particular on polyether higher molecular weights with an ethylene oxide content to 35 wt .-% ·

However, in the case of higher ethylene oxide contents, above about 20% by weight, in an endblock the copolyether alcohols become semi-solid to solid, waxy compounds which are difficult to handle under technical conditions. In addition, Blockcopolyetheralkohole with oxy! Such a molecular inconsistency has the disadvantage that polyurethanes produced therefrom have a glass transition region which extends over a relatively large temperature range. If polyether alcohols are used which already start to solidify at room temperature, Thus, it is not possible to prepare storage-stable prepolymers therefrom with certain, industrially processed isocyanates thereof.

Object of the invention

The aim of the invention is to produce Copolyetheralkohole of two or more alkylene oxides and a starter or initiator mixture in the presence of alkaline, anionic catalysts, which are in a liquid state at room temperature, have a low number of double bonds and by a distinguish high molecular uniformity ·

Explanation of the essence of the invention

The object of the invention is achieved by means of a process for the preparation of copolyether alcohols of average molecular weight 500 to 20,000 and a hydroxyl functionality of 1 to 5 by alkaline catalyzed copolymerization of at least two alkylene oxides in the presence of at least one compound having 1 to S hydroxyl groups as initiator in at least two process stages at temperatures between 20 and 150 ⁰ C and at pressures of 0.1 to 2.5 MPa · The alkaline doped polyhydroxyl compound to erfindungsgemäE initially with a mixture of at least two alkylene oxides in a weight ratio of 99: 1 to 1: 1 converted and after a If appropriate, further intermediate addition of the more reactive alkylene oxides, the reaction product formed in a further reaction step with a mixture of at least two alkylene oxides in a weight ratio of 1: 1 to

1: 99 reacted ·

Such prepared copolyether alcohols consist either of several blocks of an alkylene oxide with 0.5 to 5 % of another alkylene oxide or a part of the polyether chain consists of alternating blocks of two alkylene oxides with aa longer end block of an alkylene oxide with 1 to 10 % of another statistically distributed alkylene oxide. For example, according to the invention, a first block of 99 to 50% by weight of propylene oxide and 1 to 50% by weight of ethylene oxide and a second block of 99 to 50% by weight of ethylene oxide and 1 to 50% by weight of propylene oxide are prepared with random distribution , For this purpose, during a so-called endurance phase, a residue of an alkylene oxide remaining in the reaction phase is advantageously reacted together with a further, re-mixed alkylene oxide. Carrying out the process according to the invention is technically easy to realize and can be successfully used both in reactors with continuous and discontinuous operation. The procedure described gives copolyether alcohols which have a low dispersity in the polyoxyethylene block and which have processing advantages. They are liquid up to high ethylene oxide contents and thus over a wide range of hydrophilic / hydrophobic balance at room temperature. In addition, as a result of the procedure described effects in terms of energy savings and increase the space-time yield can be achieved by the stoppage phase is shortened after the metering of the less reactive alkylene oxide or completely eliminated, can. In this way, it is possible to adjust the predetermined content of ethylene oxide in the less reactive alkylene oxide and to achieve the desired low dispersity.

Examples of suitable polyhydroxy compounds are water, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropyl glycol, tripropylene glycol _. ^., 63-alkanediols »trimethylolpropane, glycerol, pentaerythritol, xylitol, sorbitol and similar compounds.

The alkaline doping can be carried out both by alkali metal hydroxides or their aqueous solutions with subsequent dehydration and by dissolving alkali metal in the hydroxyl compound. The addition of organic alkali metal solutions is also possible ·

Propylene oxide, butylene oxide, epichlorohydrin and styrene oxide are exemplified as "propylene oxide, butylene oxide, epichlorohydrin and styrene oxide." In general, the initiator and catalyst are mixed together and, if water is not used or added, stirred under the effect of temperature and reduced pressure. This dehydration can be done by stripping at temperatures of 60 to 150 ⁰ C · this gives a starter precursor, which is then reacted with the alkylene oxides. For this purpose, first a mixture of at least two alkylene oxides at 20 to 150 ⁰ C, preferably at 80 to 120 C added such that initially a higher than the reaction temperature is used and then stabilized to the desired Reaktionsteaiperatur · After completion of the dosage remains a balance of From 0.01% to 5% by weight of the less reactive alkylene oxide which is consumed by addition of one or more further alkylene oxides to a slurry and further added to the prepolymer, either immediately or within from 1 to 120 minutes, preferably from 5 to 30 minutes »After completion of the addition, the state of the art is neutralized and worked up.

embodiments

example 1

A mixture is prepared from 2/8 kg of dipropylene glycol and 140 ml of 50% strength potassium hydroxide solution in a 4 l round-bottomed flask. This mixture is dehydrated at 80 ° C. and 0.1 torr for 4 hours on a vacuum rotary evaporator. A starter precursor with a water content of below 0.01 % · This starter precursor is placed in a 50 liter autoclave · while it is heated to 100 C, is purged with nitrogen »Thereafter, within 5 hours, a mixture of 28.1 kg of propylene oxide and 4.4 kg ethylene oxide trains -

give. After completion of the addition and a short hold period of 10 minutes, the prepolymer still contains 3.6% by weight of propylene oxide, which represents 11 % of the 8.8 kg of ethylene oxide subsequently metered in within one hour. The propylene oxide is slowly consumed with this Neutralization with 10% HCl and dewatering and filtration of a polyetherdiol having the following properties:

Hydroxyl number: 50.6

Oodzahl: 0.24 Mn: 2100 Mw: 2250 Mw / Mn: 1.07 r \ (20 ^° C): 560 mPas. Example 2

From 4.02 kg of dipropylene glycol and 220 g of metallic potassium, a starter precursor is prepared at 85 ⁰ C under nitrogen · After all potassium is dissolved, the product is placed in an 80 1 autoclave, rinsed with nitrogen at 85 ⁰ C and stirred · Thereafter a mixture of 43.75 kg of propylene glycol and 12.9 kg of ethylene oxide at 105 ⁰ C is metered in such a way that a pressure of 3 atm is maintained, After 3 hours 30 minutes, the recording is completed. During a sustained period of 30 minutes, the pressure drops to 1.5 atm. The content of propylene oxide is then 0.17 % (according to Gaschromatogramra). Subsequently, a mixture of 12.9 kg of ethylene oxide and 0.7 kg of propylene oxide is added and added at 100 ° C / 2.5 atm within 1 hour. It is then neutralized, dehydrated and filtered. The product has the following properties:

Hydroxyl number: 45.5 3 number: 0.21

Mn: 2350

Mw: 2500 Mw / Mn: 1.06

(20 ^° C): 608 mPas.

-2 ^ 11933 * 0 ^ 95

Example 3

It is prepared according to Example 1 from 1.25 kg of ethylene glycol and 140 ml 50 % ± ca potassium hydroxide starter precursor · For this purpose, in a 50 1 autoclave at 100 ⁰ C under a pressure of 6.5 atm, a mixture of 5.2 kg of ethylene oxide and 15.5 kg of propylene oxide added · After a good 2 hours, the recording is completed. After 5 minutes, the addition of a mixture of 10.0 kg of ethylene oxide and further 1 kg of propylene oxide begins immediately with a residual content of propylene oxide of 3.1 % . The addition is complete after 1 hour. It is then neutralized, stripped, filtered off with suction and finely dewatered. The product has the following properties:

Dihydroxy number: .67,0 Dodzahl: 0.16 Water content: mm 0, 01 % Mn: 1630 Mw: 1700 Mw / Mn: 1.04 % {20 ⁰ C): 682 mPas.

Example 4

From 92 Tin. Glycerol and 10 Tin. 50% potassium hydroxide solution is prepared in a round bottomed flask. This is dehydrated at 80 ° C and 1 Torr for 3 hours.

Thereafter, it is transferred to a 4.5 1-sulphonation with stirrer, reflux condenser, cold finger with dry ice cooling via a dropping funnel and thermometer. In this flask, the starter mixture is heated to 100 ⁰ C and at 100 i 10 ⁰ C, a mixture of 2660 TIn. Propylene oxide and 300 Tin "ethylene oxide added dropwise within 6.5 hours · After completion of the addition, additional 750 parts of ethylene oxide are added dropwise with stirring without an intermediate break. After completion of the addition, the mixture is stirred for 10 minutes at 100 ⁰ C, then adjusted with 10 Soiger hydrochloric acid to a pH of 5 and stirred at 100 ⁰ C for 1 hour. Thereafter, excess hydrochloric acid and water at reduced pressure

distilled, filtered off the precipitated salts at a water content of about 0.4%, and then at 0.1 torr and 120 ⁰ C dried finely · gives a polyether triol following characteristic properties:

Hydroxy number: 45.2 dod number: 0.35

Mn: 3500

Mw: 3750 Mw / Mn: 1.0.7

F. (Mn / OH equiv.): 2.76

Example 5

Analogously to Example 4, a starter mixture of propylene oxide is from 138 Tin · glycerol and 30 Tin · 50% strength potassium hydroxide solution and at 80 ⁰ G 390 Tl. Added dropwise.

The prepolymer thus obtained is transferred to a 6 liter sulphonation flask with the same equipment as in Seispiel 4. At 100 i 10 ⁰ C, a mixture of 3600 Tin · propylene oxide and 450 Tin. Ethylene oxide is added with stirring within 7.5 hours · After completion of the addition immediately further 1125 Tl. Ethylene oxide are added without an intermediate break. After working up as in Example 4, a polyether triol having the following properties is obtained:

hydroxyl number: 44.5 Oodzahl: 0.28 Mn: 3550 Mw: 3800 Mw / Mn: 1.07 F (Mn / OH equiv.): 2.82 Example 5

Analogously to Example 4 is from 46 Tin · glycerol, 31 Tin. Ethylene glycol and 20 TIn. 50 % ± ca lye solution of a starter and immediately transferred to a 4.5 1-sulphonation flask with the same equipment as in Example 4. »To this starter mixture with stirring at 100 - 5 ⁰ C within 7 hours, a mixture of 2600 TIn. Propylene oxide and 300 TIn.

Ethylene oxide is added. Thereafter, an additional 650 parts of ethylene oxide are added immediately. After a holding time of 30 minutes, the mixture is worked up as in Example 4. A polyether alcohol having the following properties is obtained:

Hydroxyl count: 40.4

Dod number: 0.38

him 3300

Mw: 3600

Rw / Mn: 1.09

F (Mn / 0H-eq): 2.38

Example 7

Into a 6 1 sulfonation flask with stirrer and RückfluS intensive condenser 40 TI are given · 20 ^ strength potassium hydroxide solution and heated to 80 ⁰ C. In the mixture are added dropwise within 1 hour at 80 i 5 ⁰ C 120 TI · propylene oxide · Thereafter, the reflux condenser is replaced with a distillation head and dehydrated at 80 ⁰ C and water jet vacuum · After about 2 hours, no water

Thereafter, the Sülierkolben is equipped as in Seispiel 4. In the starter mixture, a mixture of 3700 Tin · propylene oxide and 420 Tin · ethylene oxide is added dropwise with stirring at 100 to 110 ⁰ C in 8 hours. . Immediately after completion of the addition of ethylene oxide are more 1100 Tl within 2.5 hours at 100 without intermediate pause - 10 ⁰ C are added. A polyetherdiol having the following characteristics is obtained:

hydroxyl number: 45.0 Dodzahl: 0.24 Mn: 2450 Mw: 2600 Mw / Mn: 1.06 F (Mn / OH equiv.): 1.96

Example 8

As in Example 4134 TI · Triraethylolpropan and 30 Ti · 40% lge potassium hydroxide are reacted at a Startergeraisch and then transferred into a 6 1 sulfonation flask as in Example 4 · purpose, a Geraisch from 3400 Tin at HO to 120 ⁰ C. Propylene oxide and 600 TIn. Ethylene oxide was added over 6 hours with stirring · Immediately after completion of the addition to add additional 1020 TI · ethylene oxide "Working up is effected as in Example 4 except that TI · propylene oxide is added after the filtration again 30, stirred for 30 minutes at 80 ⁰ G, distilled again and then finely dried. A polyetherdiol having the following characteristics is obtained:

Hydroxylzahi: 33.2 Dodzahl: 0.38 Mn: 4850 Mw: 5150 Mw / Mn: 1.06 F (Mn / OH eq.): 2.87 Example 9

In a 6 1 sulfonating flask as in Example 7 are 138 Tl. Pentaerythritol in 100 TIn. 17.5 % potassium hydroxide solution dissolved at 100 ⁰ C. With stirring, 150 parts of propylene oxide are added. After a short post-reaction phase is dehydrated at 110 ° C / O, 1 Torr for 3 hours.

Thereafter, a structure as in Example 4 is selected. The Reaktionssteraperatur is maintained at 110 ⁰ C; it should not

if above 120 ⁰ C increase. With stirring, within 7 hours, a mixture of 3440 Tin »propylene oxide and 330 TIn. Ethylene oxide added * Immediately thereafter, add another 710 TI · ethylene oxide in 1 hour. Thereafter, it is worked up as in Example 8. A polyether tetrol of the following properties is obtained:

Dihydroxy number: 48.3 iodine: 0.19 Mn: 4400 Hw: 4900 Mw / Mn: 1.11

F (Mn / OH equi ♦): 3.79

Claims (5)

invention claim 1. A process for the preparation of Gopolyetheralkoholen the average molecular weight 500 to 20,000 and a hydroxyl functionality of 1 to 6 by alkaline catalyzed copolymerization of at least two alkylene oxides in the presence of at least one 1 to 6 hydroxyl-containing compound as a starter in at least two process stages at temperatures between 20 and 150 ⁰ C and at pressures of 0.1 to 2.5 MPa, characterized in that the alkaline-doped hydroxyl compound is first reacted with a Geraisch of at least two alkylene oxides ira weight ratio 99: 1 to 1: 1, wherein a further addition of the intermediate more reactive alkylene oxide is possible, and subsequently the reaction product formed is reacted in a further reaction step with a mixture of at least two alkylene oxides in a weight ratio of 1: 1 to 1:99 2 * Method according to item 1, characterized in that several blocks of an alkylene oxide are prepared with 0.5 to 5% of a further alkylene oxide · 3 · Method according to item 1, characterized in that a part of the polyether chain consists of alternating blocks of two alkylene oxides with a longer end block of an alky-1-enoxide with 1 to 10 % of another statistically distributed alkylene oxide. 4. Method according to item I, characterized in that a first block comprises from 99 to 50% by weight of propylene oxide and from 1 to 50% by weight of ethylene oxide and a second block of from 93 to 50% by weight of ethylene oxide and from 1 to 50% by weight »-% Propylene oxide with statistical distribution» Method according to item 1, characterized in that, during a hold-up phase, a residue of an alkylene oxide remaining in the reaction atmosphere is reacted together with another, re-mixed alkylene oxide.