GB2166738A

GB2166738A - Process for the preparation of addition products of epoxides and compounds containing an active hydrogen

Info

Publication number: GB2166738A
Application number: GB8528001A
Authority: GB
Inventors: Daniel Falgoux; Jean-Claude Joly; Daniele Simoulin
Original assignee: BP Chemicals Ltd
Current assignee: BP Chemicals Ltd
Priority date: 1984-11-13
Filing date: 1985-11-13
Publication date: 1986-05-14
Also published as: FR2573067A1; GB8528001D0; FR2573067B1

Abstract

Addition products of epoxides and compounds containing an active hydrogen atom are obtained by conducting the reaction in the homogeneous liquid phase, in the presence of a catalyst consisting of a perchlorate of a metal in a valency state at least equal to 3. Selectivity for the 1:1 adducts is thereby improved. Suitable active hydrogen compounds include alcohols, phenols, amines, carboxylic acids and water.

Description

SPECIFICATION Process for the preparation of addition products of epoxides and organic compounds comprising an active hydrogen The present invention relates to a process for the preparation of addition products of epoxides and organic compounds comprising an active hydrogen, by a catalytic reaction carried out in the homogeneous liquid phase.

It is known that an organic compound comprising an active hydrogen can be added to an epoxide in the presence of various catalysts. Such reactions generally result in a mixture of addition products having one, two or more molecules of epoxides per molecule or organic compound comprising an active hydrogen being formed. The preferred product is that obtained by reacting one molecule of organic compound comprising an active hydrogen with one molecule of epoxide. The selectivity(s) is defined as being the the ratio by weight of the quantity obtained of this product to the quantity of the product obtained by reacting one molecule of organic compound comprising an active hydrogen with two molecules of epoxide.

Examples of addition products which can be obtained by such reactions, are the monoalkylethers of monoalkyleneglycol or dialkyleneglycol which are prepared by reacting an alcohol with an epoxide. Other examples of addition products are non-ionic surface-active substances prepared in a similar manner by reacting an epoxide such as ethylene oxide or propylene oxide with a higher alcohol, or a carboxylic acid such as a fatty acid, or a phenol, or an amine.

It is already known that as catalysts for this addition reaction one may use compounds having a basic character, which are soluble in the reaction medium, such as the hydroxides of the alkali metals, or the alcoholates of these metals. These catalysts are very active, but they have the drawback of leading to addition reactions which are not very selective.

It is also known to use catalysts of an acid character which are soluble in the organic compounds comprising an active hydrogen in particular strong acids such as sulphuric acid and sulphonic acids, or boron trifluoride. However, these catalysts, whilst leading to an excellent selectivity and having a high catalytic activity, cannot be used in the current industrial reactors, because of their corrosiveness towards metal.

Moreover, they can also give rise to undesirable side reactions. Thus in the case of the reaction between ethylene oxide and alcohol a side reaction forming 1-4-dioxane, which is a toxic substance, can occur.

Other catalysts consisting of neutral mineral salts which are soluble in the organic compounds comprising an active hydrogen atom have also been used. Such catalysts, for example sodium fluroborate, are highly selective but possess low catalytic activity.

The phosphomolybdates and phosphomolybdic acid which are also known catalysts, have the advantage of being selective, substantially non-corrosive and without risk. Unfortunately, these catalysts have a relatively low activity and have to be used at high concentrations to be effective.

As catalysts for the addition reaction of a epoxide and an organic compound comprising an active hydrogen perchlorates of metals in a valency state equal to 2 are also known, for example, the perchlorates of magnesium, calcium, manganese, nickel and zinc. These salts which are very selective in this addition reaction nevertheless have a medicore catalytic activity. Therefore to obtain, in an industrial plant, a complete conversion of the epoxide, the quantity of these salts used must be relatively great, for example between 100 and 10,000 ppm by weight of the reaction mixture.During purification by distilling the addition reaction products however, these salts subjected to a high temperature are concentrated in particular in distillation residues up to quantities such that the risks of explosion due to their thermal decomposition become considerable, which greatly limits the industrial-scale use of these salts as catalysts in this addition reaction.

It is also possible to use as catalysts for this addition reaction the salts of trifluoromethanesulphonic acid. These catalyst, although both active and selective, are expensive and therefore of limited industrial interest.

The Applicant has now found catalysts for the preparation of addition products of an epoxide and an organic compound comprising an active hydrogen. These catalysts, which are soluble in the reaction medium, have both an extremely high activity and a high selectivity, yet do not present an explosion risk and are not corrosive in respect of the usual metals. Furthermore, these catalysts may be employed over a wide temperature range, extending from 30 C to 200"C and preferably from 50"C to 180"C.

The object of the present invention is therefore a process for the preparation of addition products of expoxides and organic compounds comprising an active hydrogen which process comprises reacting an epoxide with an organic compound comprising an active hydrogen in the homogenous liquid phase and in the presence of an effective amount of a metal perchlorate catalyst characterised in that the metal perchlorate catalyst is a perchlorate of a metal belonging to Groups III to VIII of the Periodic Table of Elements said metal being in a valency state of greater than or equal to 3.

According to the invention any epoxide may in principle be used. However, preference is given to substituted or unsubstituted lower alkylene oxides, e.g. ethylene oxide, propylene oxide or butylene oxide, and epichlorhydrin.

The organic compounds comprising an active hydrogen may be chosen from amongst a large number of organic compounds and include compounds such as alcohols, aromatic alcohols, amines and carboxylic acids or esters thereof. Water is also included in the definition of an organic compound comprising an active hydrogen although it is not strictly an organic compound. The alcohols employed may be primary or secondary aliphatic alcohols comprising from 1 to 20 carbon atoms. It is generally preferred to use lower primary aliphatic alcohols such as methanol, ethanol propanol and n-butanol. However, very good results may also be obtained with heavier primary aliphatic alcohols comprising up to 20 carbon atoms, such as for example n-octanol or dodecanol, or with the secondary aliphatic alcohols such as isopropanol or secondary butanol, or the monoalkylethers of alkyleneglycols.This is because the catalysts of the present invention have good activities and selectivities.

Suitable primary or secondary aliphatic amines are those comprising for example from 1 to 20 carbon atoms suitably 1 to 6 carbon atoms, Carboxylic acids, or esters thereof, having from 1 to 20 carbon atoms may also be used, as well as substituted or unsubstituted aromatic alcohols e.g. phenols.

According to the invention the organic compound comprising an active hydrogen is generally used in a large excess by weight in relation to the epoxide, the ratio by weight of the quantity of organic compound comprising an active hydrogen atom to that of the epoxides being for example comprised between 2 to land 20 to 1.

The catalysts used comprise, perchlorates of metals which belong to Groups lil to VIII of the Periodic Table of Elements and which are in a valency state of greater than or equal to 3. Suitable catalysts are the perchlorates of metals belonging to Groups III, IV , V, VI and VIII of this Table, preferably the perchlorates of aluminium, gallium, indium, thallium, titanium, zirconium, hafnium, tin, vanadium, chromium, or iron. Of these it is particularly preferred to use aluminium perchlorate.

The metal perchlorates used as catalysts according to the invention may be easily obtained by processes of preparation well known in themselves. In particular, the metal perchlorates referred to above may be prepared by the action of perchloric acid on the appropriate metal or on an oxide, hydroxide or carbonate of the said metal.

The quantity of metal perchlorate empioyed in the addition reaction must be sufficient to obtain the desired catalytic effect. It has surprisingly been found that the quantity of metal perchlorate required is generally extremely small and is much less than the quantities of catalysts, such as the perchlorates of potassium, magnesium, zinc, calcium, maganese or nickel, which have been used previously. It has now therefore become possible to employ metal perchlorate catalysts in the addition reaction of an epoxide and an organic compound comprising an active hydrogen without the risk of explosion, since (1) these perchlorates possess excellent thermal stability and (2) they are used at extremely low levels of concentration.

The quantity of metal perchlorate used in the addition reaction of an epoxide and an organic compound comprising an active hydrogen atom may suitably be between 1 and 100 ppm by weight of the reaction mixture. The exact amount used will depend especially on the nature of the reactants present, the temperature of the reaction and the residence times. For example, in the case of the use of alcohols or primary amines comprising from 1 to 6 carbons, the catalytic effect is perceptible at concentrations of less than or equal to 1 ppm although concentrations comprising between 1 and 50 ppm are preferred.In the case of reactions involving higher alcohols, or amines comprising at least 7 carbon atoms, or other organic compounds comprising an active hydrogen atom such as phenols, monoalkylethers of alkylene glycols and carboxylic acids, the metal perchlorate concentrations in the reaction mixture are generally in the range 10 and 100 ppm.

The reaction proceeds in a homogeneous phase at a temperature suitably between 30"C and 200"C and preferably between 50"C and 180"C, under a pressure sufficient to maintain the reaction mixture in the liquid state e.g. 2.5 to 4.0 Mpa. Furthermore the reaction may be performed in standard apparatus such as for example steel autoclaves, optionally provided with a stirrer, or tubular reactions which may operate under pressure.

The object of the following Examples is to illustrate the present invention.

Example 1 Into a 5-litre steel vessel provided with a stirrer system, there are introduced 1400 g of ethanol and 15.4 mg of aluminium perchlorate. The mixture obtained is subjected to scavenging with gaseous nitrogen in order to eliminate the air present. There are then introduced 140 g of ethylene oxide and the stirring is maintained in order to homogenised the mixture The concentration of aluminium perchlorate in the reaction mixture is equal to 10 ppm.

The reaction mixture obtained as above is fed, by means of a dosing pump, to a tubular reactor consisting of a stainless steel tube with an internal diameter of 4 mm and 50 m in length. The tubular reactor is located in a thermal chamber, maintained at 150 C. The pressure inside the reactor is maintained constant at 3 MPa. The feed of the tubular reactor is regulated so that the mean residence time of the reaction mixture in the reactor is equal to 2 hours After passing through the tubular reactor the reaction mixture is cooled through a cooling coil. The reaction mixture is then analysed by chromatography to determine its composition.

The results are provided in Table 1. It is found that the conversion of ethylene oxide is complete, that is to say that the conversion rate of the ethylene oxide is equal to 1.00. The quantities of monoethyleth ers of monoethyleneglycol, diethyleneglycol, and triethyleneglycol at the end of the reaction (expressed as a percentage by weight in relation to the reaction medium) are equal to 20.0%, 1.6% and 0.1% respectively. The ratio by weight of the quantity of monoethylether of monoethyleneglycol produced to that of monoethylether of diethyleneglycol, or the selectivity S of the reaction is therefore equal to 12.5.

Example 2 In this Example the operating conditions are identical to those of Example 1, except for the fact that the temperature of the chamber in which the tubular reactor is located is maintained at 80"C instead of 1500C, and the mean residence time of the reaction mixture in the reactor is equal to 5 hours instead of 2 hours. The results are shown in Table 1.

Analysis of these results clearly shows the extremely high catalytic activity of the aluminium perchlorate and the high selectivity of the reaction when conducted in the presence of this catalyst. In particular it should be noted that for a catalyst concentration as low at 10 ppm, the aluminium perchlorate permits of a total conversion of the ethylene oxide even at a relatively low temperature.

Example 3 (comparative) By way of comparison, Example 3 was carried out under identical operating conditions to those of Example 1, except for the fact that instead of the aluminium perchlorate at a concentration of 10 ppm, potassium acetate of the formula CH3COOK at a concentration of 300 ppm was used.

The results given in Table 1 show that potassium perchlorate is inferior to aluminium perchlorate as regards the selectivity parameter(s).

TABLE 1 CATALYST K 2) EXAMPLE Temper- Mean Conver- S Nature Concentra- ature Residence sion rate (Selec- tion (p pm) (;;C) Time (hers) of the tivity) oxide 1 Al(ClO4) 10 150 2 1.00 12.5 2 Al(ClO4)a 10 80 2 1.00 11 3 CH3COOK 300 150 2 1.00 5.7 (1) Conversion rate of ethylene oxide: ratio of the quantity of ethylene oxide which has reacted to that employed (2) Selectivity defined by - ~ weight of monoethylether of monoethyleneglycol produced weight of monoethylether of diethyleneglycol produced Example 4 In this example the operating conditions are identical to those of Example 1, except for the fact that in the preparation of the reaction mixture, 1400 g of ethanol are replaced by the same weight of n-butanol, and that furthermore, aluminium perchlorate is used at a concentration of 30 ppm instead of 10 ppm.

Table 2 shows the results of the production of monobutylether of ethyleneglycol. These results shows the extremely high catalytic activity of the aluminium perchlorate in the reaction between n-butanol and the ethylene oxide, and also the high selectivity of the reaction for monobutylether of monoethyleneglycol.

Example 5 (comparative) By way of comparison, Examples were carried out under operating conditions identical to those of Example 4, except for the fact that instead of aluminium perchlorate at a concentration of 30 ppm, magnesium perchlorate of the formular Mg(CIO4)2, at a concentration of 300 ppm was used.

The results given in Table 2 show that despite a concentration of catalyst very much higher than that of Example 4, the conversion rate of the ethylene oxide is only equal to 0.71. In turn, the selectivity of the reaction in the presence of magnesium perchlorate, which is equal to 12.5, is little different from that obtained with aluminium perchlorate.

Example 6 (comparative) By way of comparison Example 6 was carried out under operating conditions identical to those of Example 4, except for the fact that instead of aluminium perchlorate at a concentration of 30 ppm, zinc perchlorate of the formula Zn(CIO4)2 at a concentration of 300 ppm was used.

The results given in Table 2 show that, despite a concentration of catalyst very much higher than that of Example 4, the conversion rate of ethylene oxide is only equal to 0.96, the selectivity of the reaction being slightly less than that obtained with aluminium perchlorate.

TABLE 2 CATALYST (1) 2) EXAMPLE Temper- Mean Conve- S Nature Concentra- ature Residence sion rate {Selec- tion (p pm) pC) Time (hers) of tivity) ethylene oxide 4 Al(CI04)3 30 150 2 1.00 12.8 5 Mg(CIO4)2 300 150 2 0.71 12.5 6 Zn(CIO4)2 300 150 2 0.96 9.1 (1) Conversion rate of ethylene oxide: ratio of the quantity of ethylene oxide which has reacted to that employed.

(2) Selectivity defined by weight of monobutylether of monethyleneglycol produced weight of monobutylether of diethyleneglycol produced

Claims

1. A process for the preparation of addition products of epoxides and organic compounds comprising an active hydrogen which process comprises reacting an epoxide with an organic compound comprising an active hydrogen in the homogenous liquid phase and in the presence of an effective amount of a metal perchlorate catalyst characterised in that the metal perchlorate catalyst is a perchlorate of a metal belonging to Groups Ill to VIII of the Periodic Table of Elements said metal being in a valency state of greater than or equal to 3.

2. A process as claimed in claim 1 characterised in that the metal perchlorate is selected from the perchlorates of aluminium, gallium, indium, thallium, titanium, zirconium, hafnium, tin, vanadium chromium or iron.

3. A process as claimed in claim 2 characterised in that the metal perchlorate is aluminium perchlorate.

4. A process according to Claim 1, characterised in that the epoxide is selected from ethylene oxide, propylene oxide, butylene oxide or epichlorhydrin.

5. A process according to Claim 1, characterised in that the organic compound comprising an active hydrogen atom is selected from an alcohol, an aromatic alcohol, an amine, a carboxylic acid or ester thereof or water.

6. A process according to Claim 5, characterised in that the alcohol is selected from a primary or secondary aliphatic alcohol comprising from 1 to 20 carbon atoms, or a monoalkylether of an alkyleneglycol.

7. A process according to Claim 5, characterised in that the amine is a primary or secondary aliphatic amine.

8. A process according to Claim 1, characterised in that the addition reaction is effected at a temperature between 50 and 1800C, and that the catalyst is present in an amount between 1 adn 100 ppm by weight of the reaction mixture.

9. A process according to claim 6 characterised in that the alcohol is selected from methanol, ethanol, propanol, n-butanol, octanol, dodecanol, isopropanol or secondary butanol.