GB1591497A - Process for the production of olefin oxides - Google Patents

Description

(54) PROCESS FOR THE PRODUCTION OF OLEFIN OXIDES (71) We, the Société Anonyme PROPYLOX, of 12, Avenue de la Renaissance, B-1040 Brussels, Belgium, a body corporate organised under Belgian law do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to epoxidation.

It has been previously proposed to perform epoxidations in reactors made of stainless steel or aluminium (see US patent 2,977,374). However, these reactors have a number of disadvantages. In fact, when aluminium reactors are used, serious corrosion phenomena are observed after very short operating times. On the other hand, when stainless steel reactors are used, a serious decomposition of percarboxylic acids is observed during the start-up of the equipment. The steel needs to be passivated previously for prolonged periods in order to reduce this inconvenience.

We have observed that these difficulties may be reduced by a process for the production of olefin oxides by the epoxidation of the corresponding olefins by means of percarboxylic acids, in which the reaction is carried out in a reactor a part of or all of whose inner surfaces in contact with the reaction mixture are of nickel or of an alloy containing nickel.

It is to be understood that the epoxidation may be total, or else partial, as may be the case with compounds having two or more olefinic double bonds in the molecule.

It is to be understood that two or more materials selected from nickel and nickel alloys may be used in a single reactor.

Advantageous alloys containing nickel are those alloys containing at least 15 wt. % and preferably at least 20 wt. %nickel. Usually, alloys containing 20 to 90 wt.%nickel are used.

The alloys containing nickel which can be used according to the process of the invention generally contain at least one other metal selected from among chromium, copper, iron, cobalt, molybdenum, manganese and silicaon. Usually, they contain 20 to 90 wt.% nickel, 0 to 1 or 35 copper, 0 to 5% cobalt, 0 to 50 or 80% iron, 0 to 5% manganese, 0 to 25% chromium, 0 to 10%silicon, 0 to 30% molybdenum and 0 to 7%other elements.

As particularly suitable alloys, there can be mentioned especially the alloys which are usually referred to by the Registered Trade Marks INCONEL, INCOLOY, HASTELLOY, NIMONIC or the trade names NI-RESIST and CHLORIMET. Alloys of the types INCONEL and INCOLOY are particularly appropriate. The best results have been obtained with alloys containing 60 to 80% nickel, 10 to 25 % chromium, 5 to 20% iron, 0 to 5% of at least one element selected from among manganese, molybdenum, silicon, copper, cobalt, thatalum and carbon or else with alloys containing 30 to 80% nickel, 10 to 25% chromium, 5 to 40%iron, 0.1 to 8% molybednum and 0 to 5% of at least one element selected from among manganese, silicon, copper, cobalt, tantalum and carbon.

The reactors may be made entirely of nickel or of a nickel alloy, or may be clad inside by one of these products. They may be of one of the various types known per se. In general, reactors are used which promote thermal exchange in such a way that the reaction temperatures can be better controlled. Tubular reactors or autoclaves can thus be used.

Tubular reactors are highly suitable. Of cours,e other reactors may also be suitable.

The process according to the invention applies to the epoxidation of various types of olefins. In principle, all compounds containing at least one carbon - carbon double bond can be used in the process according to the invention. However, the process is preferably applied to olefins which contain .C = CH2, - CH = CH - or -CH = CH2 groups. In general, the process according to the present invention is applied to alkenes or cycloalkenes containing a total of 2 to 30 carbon atoms in their molecule. The process may, however, also be applied to the epoxidation of unsaturated polymers such as polybutadienes. The alkenes or cycloalkenes to which the process can be applied may be either unsubstituted or substituted by one or more substituents selected from the alkyl groups which generally contain 1 to 4 carbon atoms, cycloalkyl groups, aryl groups, or substituents containing heteroatoms.

Among the alkenes or cycloalkenes which are either unsubstituted or substituted only by alkyl, cycloalkyl or aryl groups and to which the process according to the invention applies, the following can be mentioned in particular: ethylene, propylene, methylpropene, butenes, butadiene, pentenes, pentadienes, especially isoprene, hexenes, hexadienes, diisobutylene, octenes, decenes, a-pinene,p-menthene, tri- and tetrapropylenes, tetradecene, hexadecene, octadecene, 1-dodecene, 1-eicosene, styrene, methylstyrene, vinyltoluene, vinylcyclohexane and vinylcyclohexene, cyclohexene, limonene, divinylbenzene and stilbenes.

Alkenes or cycloalkenes which can be used in the process of the invention may also be substituted by one or more substituents containing heteroatoms such as halogen atoms, especially chlorine, fluorine and bromine atoms, sulphonic or phosphoric groups, hydroxy, alkoxy, carboxy, acyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, acylamino, arylamido, alkylamido, imido or nitrilo groups.

Among the unsaturated halogen derivatives which can be used, the following can be mentioned in particular: allyl and methylallyl chlorides and crotyl bromide. Among the unsaturated alcohols which can be used, the following can be mentioned in particular: allyl alcohol, methylallyl alcohol, crotyl alcohol, methyl vinyl carbinol and oleyl alcohol. As unsaturated ethers which are highly suitable, ethyl allyl ether, the acetals of acrolein, and ethyl oleyl ether can be mentioned. Among the unsaturated esters which are highly suitable are the esters of unsaturated acids such as acrylic, methacrylic, crotonic, sorbic and maleic acids with saturated or unsaturated alcohols, as well as the esters of saturated acids with unsaturated alcohols such as allyl, methylallyl or oleyl alcohol. The process of the invention can be applied in particular to methyl acrylate, ethyl methacrylate, allyl crotonate, diethyl maleate, oleyl acetate, allyl acetate, methylallyl acetate and allyl propionate. Unsaturated ketones and aldehydes can also be used in the process of the invention although, in the latter case, competitive oxidation reactions of the aldehyde function may occur. As suitable ketones or aldehydes, methyl vinyl ketone, methyl allyl ketone, mesityl oxide, phorone, acrolein, crotonaldehyde and cinnamaldehyde can be mentioned. Among the unsaturated amides to which the process according to the invention can be applied is allylacetamide.

Other examples of olefins to which the process of the invention can be applied are described in USP 2977374 mentioned above.

The process according to the invention is most particularly suitable for the epoxidation of propylene, allyl alcohol and allyl chloride.

Various types of percarboxylic acids can be used in order to carry out the present invention.

Mono- or polypercarboxylic acids can be used. In general, monopercaboxylic acids are used, and most frequently percarboxylic acids containing 1 to 10 carbon atoms, for example performic acid, peracetic acid, percyclohexanoic acid, perpelargonic acid, perpropionic acid, perbenzoic acid, mono and di-perphthalic acids, chloroperacetic acids, perbutyric acid and permaleic acids. For the epoxidation of propylene to epoxypropane, perpropionic or peracetic acid is preferably used. For the epoxidation of allyl chloride or allyl alcohol to epichlorhydrin and glycidol respectively, perpropionic acid is also preferably used. Other peracids may, of course, also be suitable.

The molar ratio of peracid to olefin to be epoxidised is generally between 0.01 and 20, preferably between 0.1 and 10. Other molar ratios may also be suitable.

The peracids used in the process according to the invention may be prepared in any manner knownper se. In particular, they can be prepared by the reaction of the corresponding acids with hydrogen peroxide in the presence of an acid catalyst, possibly in the presence of a solvent. If this is the case, this latter may be identical to the solvent which may possibly be used for the epoxidation.

The epoxidation reaction is generally carried out in the presence of at least one solvent which may be chosen from among water and organic solvents. As organic solvent one generally uses aliphatic, aromatic, cycloaliphatic and aryl aliphatic hydrocarbons which may be halogenated, saturated esters, saturated ethers, nitrated derivatives and alkyl, cycloalkyl and aryl phosphates. One can of course also use mixtures of these solvents with one another or with other solvents.

As examples of hydrocarbons which are highly suitable for carrying out the process of the invention, hydrocarbons containing 5 to 15 carbon atoms can be mentioned, such as petroleum ether, hexane, benzene, ethylbenzene, toluene and xylenes. As halogenated hydrocarbons, halogenated hydrocarbons can be mentioned which contain 1 to 8 carbon atoms substituted by at least one halogen, and in which at least one of the halogens is a chlorine atom such as dichloromethane, 1 ,2-dichloroethane, 1,1-dichloroethane, 1,1,2trichloropropane, 1,2-dichloropropane, 1,3-dichloropropane, trichloroethylene, perchloroethylene, chloroform, ethyl chloride, carbon tetrachloride, chlorobenzene and benzyl chloride. As examples of saturated esters, mono or polyesters can be mentioned which contain 2 to 20 carbon atoms such as methyl acetate, n-butyl acetate, ethyl acetate, diethyl phthalate, and di-n-butyl phthalate. As examples of saturated ethers, there can be mentioned more particularly aliphatic or alicyclic ethers containing from 2 to 20 carbon atoms such as diethyl ether, ethyl propyl ether, diisopropyl ether, methyl propyl ether, dioxane, dibutyl ether and methylal. As examples of nitrated derivatives, there can be mentioned nitrated derivatives which contain 1 to 10 carbon atoms, such as nitrobenzene. As examples of phosphates, there can be mentioned in particular phosphates which contain 3 to 30 carbon atoms such as trimethyl, tributyl or trioctyl phosphates.

In general, a hydrophobic organic solvent is used which is inert under the reaction conditions and which consequently includes no active hydrogen. The preferred solvents are halogenated hydrocarbons and aromatic compounds.

For the production of oxides of olefins containing 3 carbon atoms such as propylene, allyl chloride and allyl alcohol, the solvents most frequently used are chosen from among dichloropropanes, trichloroethylene, perchloroethylene, benzene, toluene, chlorobenzene, ethyl acetate and acetone.

The reaction solvent may be used in greatly varying amounts depending in particular on the solubility of the olefin to be epoxidised. In general, the reaction mixture contains 0.1 to 50 wt.

% olefin in relation to the weight of the solvent.

The reaction medium may also contain other constituents in small amounts, such as polymerisation inhibitors, peracid stabilisers or sequestering agents.

The epoxidation reaction may be carried out at temperatures between 0 and 1500C, preferably between 15 and 1200C. Other temperatures may also be suitable. The reaction pressure is sufficient to maintain at least one liquid phase; it is generally between 0.05 and 80 kg/cm2, absolute. The reaction temperature and pressure depend, of course, on the particular nature of the olefin to be epoxidised. Thus, a temperature between 20 and 100"C and a - pressure of 0.8 to 30 kg/cm2 absolute are most frequently used for epoxidising propylene. For epoxidising allyl chloride and allyl alcohols, a temperature between 20 and 150 0C and a pressure between 0.1 and 10kg/cm2 absolute are most frequently used.

The process according to the invention makes it possible to greatly reduce the corrosion observed in the epoxidation reactor when conventional processes are used. Also, a substantial reduction in the decomposition of the reaction solvents under the conditions of operation is observed. This effect is particularly noticeable when the process is applied for the epoxidation of olefins in halogenated solvents such as for example 1, 2- and 1,3dichloropropane.

The olefin oxides are used as synthetic intermediates or as monomers for the production of polymers having particular properties.

The examples below are illustrative and not limiting; they are given in order to give a better picture of the remarkable results obtained when the process according to the invention is used for the production of propylene oxide. Example 1R was carried out, by way of comparison, with an aluminium reactor. Example 2 was carried out according to the invention.

EXAMPLE 1R Into a tubular reactor made of 1.65 mm thick aluminium immersed in a thermostated bath are passed propylene and a 25 % solution of peracetic acid in dichloropropane containing 0.5 g 8-hydroxyquinoline per litre. The pressure in the reactor is 10 kg/cm2 absolute. The temperature is approx. 90-1000C. After 12 h operation, serious corrosion of the tube walls is observed and a reduction in the wall thickness at certain points to less than 0.2 mm. The yield of propylene oxide is approximately 90%in relation to the peracid introduced.

EXAMPLE 2 The same reagents as in Example 1 R are introduced into a tubular reactor of INCONEL 600. The conditions of operation are the same as in Example 1R. After 1000 h of operation no corrosion is observed. The yield of propylene oxide is 98% in relation to the peracid introduced.

Claims (21)

WHAT WE CLAIM IS:

1. A process for the epoxidation of an olefinically-unsaturated compound which comprises reacting the compound with a percarboxylic acid in a reactor at least a part of whose inner surface in contact with the reaction mixture is of nickel or of an alloy containing nickel.

2. A process for the epoxidation of an olefinically-unsaturated compound which comprises reacting the compound with a percarboxylic acid in a reactor at least a part of whose inner surface in contact with the reaction mixture is of nickel.

3. A process for the epoxidation of an olefinically-unsaturated compound which comprises reacting the compound with a percarboxylic acid in a reactor at least a part of whose inner surface in contact with the reaction mixture is of an alloy containing nickel.

4. A process as claimed in claim 3, wherein the alloy contains, by weight, at least 15% of nickel.

5. A process as claimed in claim 4, wherein the alloy contains, by weight, from 20 to 90% of nickel.

6. A process as claimed in claim 5, wherein the alloy contains, by weight, 20 to 90% nickel, 0 to 3% copper, 0 to 5% cobalt, 0 to 80% iron, 0 to 5% manganese, 0 to 25% chromium, 0 to 10%silicon, 0 to 30% molybdenum and 0 to 7%in total of other elements.

7. A process as claimed in claim 6, wherein the alloy contains, by weight, 60 to 80% nickel, 10 to 25% chromium, 5 to 20% iron, and 0 to 5% in total of at least one element selected among manganese, molybdenum, silicon, copper, cobalt, tantalum and carbon.

8. A process as claimed in claim 6, wherein the alloy contains, by weight, 30 to 80% nickel, 10 to 25%chromium, 5 to 40%iron,0.1 to 8%molybdenum and 0 to 5%in total of at least one element chosen from among manganese, silicon, copper, cobalt, tantalum and carbon.

9. A process as claimed in any one of claims 1 to 8, wherein the reaction is carried out in the presence of a solvent.

10. A process as claimed in claim 9, wherein the solvent comprises an aliphatic, aromatic, cycloaliphatic or arylaliphatic hydrocarbon; an aliphatic, aromatic, cycloaliphatic or arylaliphatic hydrocarbon which is halogenated; a saturated ester; a saturated ether; a nitro-compound; or an alkyl, cycloalkyl or aryl phosphate.

11. A process as claimed in claim 9, wherein the solvent comprises trichloroethylene, perchloroethylene, benzene, ethyl acetate, chlorobenzene, toluene or a dichloropropane.

12. A process as claimed in claim 9, wherein the solvent comprises 1, 2-dichloropropane.

13. A process as claimed in any one of claims 1 to 12, wherein the reaction is carried out at a temperature between 0 and 150"C.

14. A process as claimed in any one of claims 1 to 13, wherein the reaction is carried out at a pressure between 0.05 and 80 kg/cm2 absolute.

15. A process as claimed in any one of claims 1 to 14, wherein the olefinicallyunsaturated compound is propylene.

16. A process as claimed in any one of claims 1 to 14, wherein the olefinicallyunsaturated compound is allyl chloride.

17. A process as claimed in any one of claims 1 to 14, wherein the olefinicallyunsaturated compound is allyl alcohol.

18. A process as claimed in any one of claims 1 to 17, wherein the percarboxylic acid is peracetic acid or perpropionic acid.

19. A process for the epoxidation of an olefinically-unsaturated compound, which is performed substantially as described in Example 2 herein.

20. An epoxide of an olefinically-unsaturated compound which has been prepared by a process as claimed in any one of claims 1 to 19.

21. Process for the production of olefin oxides by the reaction of the corresponding olefins with percarboxylic acids, characterised in that the reaction is carried out in a reactor whose inner surfaces in contact with the reaction mixture are of nickel or of an alloy containing nickel.