IE780470L

IE780470L - Benzylidene halides

Info

Publication number: IE780470L
Application number: IE780470A
Authority: IE
Original assignee: Roussel Uclaf
Priority date: 1977-03-09
Filing date: 1978-03-08
Publication date: 1978-09-09
Also published as: DK164783B; FR2383153A1; JPS6254093B2; CH628605A5; AT356081B; DE2810305C2; CA1111447A; SE8305906D0; LU79194A1; DK164783C; NL7802393A; HU180060B; BE864674A; NL189189C; SU1028245A3; SE8305906L; GB1602161A; JPS53112824A; SE7802318L; NL189189B

Abstract

The halides according to the invention are meta-phenoxybenzylidene bromide and chloride. They are prepared from meta-phenoxytoluene by reaction with two equivalents of N-chloro- or N-bromoacetamide, N-chloro- or N-bromosuccinimide, chlorine or bromine at 30 - 150 DEG C in an inert solvent; dihalogenation is carried out selectively. The said halides can be used to give meta-phenoxybenzaldehyde by hydrolysis in basic or acidic aqueous media. [GB1602161A]

Description

46430 This invention relates to new benzylidene halides, to processes for their preparation and their use in the preparation of metaphenoxy-benzaldehyde.

The preparation of metaphenoxy-benzaldehyde has been known for a long time. The hitherto known processes for preparing this aldehyde may be classified in two categories. Thus the first type of process involves attaching a phenoxy group to a halogenated derivative of type (cf. for example M. TOMITA J. Pharm. Soc. Jap. 74 1062 - 5 (1954)). The yield from this type of process is, however, mediocre and the operative conditions are not very suitable for inciuctrial use (heating a halogenated benzoic ester and potassium phenate to about 200°C in the presence of copper and copper acetate).

In the 99cond type of hitherto known process metaphenoxy-toluene is oxidised with»for example potassium permanganate to obtain metaphenoxy-benzoic acid, which compound is then reduced to metaphenoxy-benzaldehyde (cf. G. LOCK Monatsh. 67 24-35 (1935) ). The yield from this type of process is 4 6 4 3 0 also not very high as the reduction of the acid function to an aldehyde function is generally carried out with a yield of less than 20%.

Thus, for several years,there has been a need to find a 5 process for the preparation of metaphenoxy-benzaldehyde suitable for industrial use, particularly since this aldehyde has become a product of increasing industrial significance, especially since it permits the preparation of alcohols such as metaphenoxy-benzyl alcohol and alpha-10 cyano-metaphenoxy-benzyl alcohol, which compounds are used in the preparation of cyclopropane carboxylic acid esters endowed with great insecticidal activity.

One of the theoretically-possible methods which has been considered for the preparation of metaphenoxy-benzaldehyde 15 involves carrying out a selective dihalogenation of the side chain of metaphenoxy-toluene to obtain a metaphenoxy benzylidene dihalide which, by hydrolysis, could then lead to the desired aldehyde„ This method was not however, very attractive to 20 chemists since it is well known that selective dihalogenation of the side chain of a compound containing two aromatic nuclei gives rise to difficulties because, on the one hand, of attack on the aromatic nuclei and, on the other hand, 46 4 30 of the possibility of forming mono, di or trihalogemated derivatives on the side chain. In order to reduce these undesirable side reactions it has been suggested to add a radical initiator to assist selective fixing of halogen to the side chain, thus enabling metaphenoxy-benzaldehyde to be obtained from metaphenoxy-toluene by passing throuh an intermediate of a dihalogenated derivative of the side chain (see French Patent Specification No. 2,214,676). However, even using promotors such as azo-isobutyro nitrile, phosphorus trichloride or ultraviolet radiation (cf.p.3, line 6 to 23 of French Patent Specification No. 2,214,676) and working at very high temperatures (above 220°C) which ought to have prevented fixing of the halogen to the aromatic nucleus, only complex mixtures were obtained, analysis of which showed the presence of only a small amount of metaphenoxy-benzylidene halide and from which the dihalogenated side 'chain derivatives were not isolated.

Hitherto, therefore, no satisfactory way has been disclosed to selectively halogenate the side chain of metaphenoxy-toluene (cf. lines 9 to 11, p.3 of French Patent Specification No. 2,214,676). It might therefore have been thought that the selective preparation of metaphenoxy-toluene derivatives having a halogenated side 4 6 4 3 0 chain was impracticable.

Suprisinglyhave now found that using certain specific halogenating agents and certain specific conditions, these dihalogenated side chain metaphenoxy- toluene derivatives (which have not hitherto been isolated) may be prepared with reasonable yields thus enabling these compounds to be isolated in good purity. ' Thus according to one feature of the present invention there are provided compounds of general formula I, ^ X 0 V C - H X having a purity of at least 65% by weight, wherein X represents a bromine or chlorine atom/ The compounds according to the invention are 15 metaphenoxy-benzylidene bromide and metaphenoxy-benzylidene chloride. They may be obtained,as described hereinafter, in a purity of at least 65% by weight, e.g. from 65 to 85% by weight or even in substantially pure form. In particular may be mentioned metaphenoxy-benzylidene brdmide 20 having a boiling point of from 152 to 153°C at 0.4 torr and a solidification point of +27.5°C.

The process which enables these compounds to be with a purity of at least 65% by weight prepared /comprises reacting metaphenoxy toluene with chlorinej, bromine, N-chloro- or N~bromo-acetamide or _ 5 _ 46430 N-chloro- or N-bromo-succinimide at a temperature of from 30 to 150°C and in the presence of a solvent and isolating the compound of formula I thus formed and, if required, purifying said compound of formula I, this process 5 constituting a further feature of the present invention.

The temperature at which the halogenation of the metaphenoxy- toluene is carried out is preferably from 50°C to 120°C .

It is preferred that the halogenation is carried out 10 with about two equivalents of halogenation agent. If an amount clearly less than two equivalents is used the reaction yield decreases and if an amount clearly greater than two equivalents is used the percentage of impurities increases in the resulting crude product. 15 Particularly preferred halogenation agents for the reaction are chlorine, bromine and N-bromo-succinimide.

The solvent preferably comprises a halogenated aliphatic hydrocarbon containing from 1 to 3 carbon atoms, a monocyclic aromatic hydrocarbon or a cycloalkane, 20 particularly preferred being carbon tetrachloride, carbon tetrabromide, tetrachloroethane, benzene and cyclohexane. The use of carbon tetrachloride is especially advantageous» 4 6 4 30 The reaction-is also desirably carried out in the presence of a radical initiator, preferably a labile azoic compound, or a peroxide, particularly azo-bis-isobutyro nitrile or benzoyl peroxide.

The compound of formula I is isolated and, if required, purified e.g. by rectification under reduced pressure or chromatography.

According to a particularly preferred embodiment of the present invention for preparing metaphenoxy-benzy-having a purity of at least 65% by weight, lidene bromide / metaphenoxy-toluene is reacted with N- bromo-succinimide in the presence of azo-bis-isobutyro nitrile and of carbon tetrachloride at the boiling temperature of the reaction mixture and the resulting dibrominated compound is isolated then purified by rectification.

According to a further particularly preferred embodiment of the present invention for preparing having a purity of at least 65% by weight, metaphenoxy-benzylidene bromide/ metaphenoxy-toluene is reacted with bromine in the presence of azo-bis-isobutyro nitrile and of carbon tetrachloride at the boiling temperature of the reaction mixture and the resulting dibrominated compound is isolated then purified by rectification. 4 6 4 3 0 According to a particularly preferred embodiment of the present invention for preparing metaphenoxy-benzylidene .having a purity of at least 65% by weight, chloride/metaphenoxy-toluene is reacted with chlorine in the presence of azo-bis-isobutyro nitrile and of carbon tetrachloride at the boiling temperature of the reaction mixture and the resulting dichlorinated compound is isolated then purified by rectification.

The process for preparing the compound of general in a purity of at least 65% by weight formula I/described above is simple and easy to indust- rialise. In general, depending on conditions used and especially according to the nature of the halogenation agent and the temperature and the nature of the solvent, the crude product of the halogenation reaction contains from 65% to 85% of dihalogenated derivativeo according to the invention 15 The compounds of general formula I/may be used, if as obtained desired , either / or in purified form, to prepare metaphenoxy-benzaldehyde. Hitherto it has not proved possible to obtain metaphenoxy-benzylidene chloride or bromide in a sufficiently high state of purity to enable 20 these compound to be used as a raw material in a chemical synthesis. 4 6 4 3 0 Thus according to a still further feature of the present invention there is provided a process for the preparation of metaphenoxy-benzaldehyde which comprises an aqueous medium.

The hydrolysis of metaphenoxy- benzylidene chloride or bromide may^ if desired, be carried out in the presence of a base e.g. an alkali metal carbonate and oreferably in the presence of aqueous isopropanol. The hydrolysis may alternatively, if desired, be carried out in the presence of an acid, e.g. hydrobromic acid and preferably in the presence of aqueous dimethylformamide.

It is convenient to isolate the metaphenoxy-benzaldehyde prepared according to the invention, in the form of its bisulphite e.g.: OH H C 9 46430 The bisulphite compound, which is stable and which can conveniently be purified, especially by crystallisation from ethyl acetate, may then be ' hydrolysed back to metaphenoxy-benzaldehyde which is thus obtained with 5 a high degree of purity.

The use of the compounds of general formula I in the preparation of metaphenoxy-benzaldehyde has the advantage of being simple and of providing a high yield. Also, for example by use of the bisulphite, convenient 10 isolation and purification of the aldehyde is permitted. It is thus possible, in two or three reaction stages, to obtain metaphenoxy-benzaldehyde with a high yield and under conditions lending themselves easily to industrialisation.

The following non-limiting Examples serve to illustrate the present invention., 4 6 4 30 Example 1 Metaphenoxy-benzylidene bromide 3 kg of metaphenoxy-toluene are introduced into 34 litres of carbon tetrachloride, the mixture obtained is 5 boiled and, by distillation, 4 litres of solvent are eliminated to give an anhydrous medium. The resultant mixture is cooled and 6.06 kg of N-bromosuccinimide followed by 210 g of azo-bis-isobutyro nitrile are added thereto. The mixture thus obtained is refluxed 10 for 23 hours, cooled to 20°C and agitated for 30 minutes at this temperature. The succinimide formed is removed by filtration and the filtrate is concentrated to dryness by distillation under reduced pressure, 5.845 kg of crude metaphenoxy-benzylidene bromide [bromine titre 42.5% 15 (theoretical 46.7%), which corresponds to a yield of 85% with reference to the starting metaphenoxy-toluene].

By rectification under reduced pressure metaphenoxy-benzylidene bromide is obtained in pure form, B0Pt = 152°C-153°C under 0.4 torr; solidification point + 27.5°C. 20 Analysis : C B^O (342.05) C% H% Br% Calculated: 45.65 2.95 46074 Found: 45.8 3.0 46.4 - ll - 4 6 4 3 0 Ultra-violet Spectrum (Ethanol containing 5% water) The spectrum presents a band tail at about the short wave lengths (beyond 250 ran) as well as small maxima in the region 270 to 280 nm, corresponding to a non-conjugated 5 aromatic structure of the type f-x (x being other than C or H).

Infra-red Spectrum: (On melted product) Absorptions at 1590, 1490 cm ^ characteristic of the aromatic nuclei; absorptions at 1220, 1260 Cm ^ 10 characteristic of the phenyl-o-ohenyl. 1 ink; absorption in the region 700°m characteristic of bromine.

N.M.R. Spectrum: (deuterochloroform)„ Peak at 6.56 ppm, characteristic of the hydrogen of the -CHB^; peaks from 6.84 to 7.60 ppm, characteristic of 15 the aromatic protons.

Example 2 Metaphenoxy-benzylidene bromide.

A solution of bromine is prepared by dissolving 2g 3 of azo-bis isobutyro nitrile in 240 cm of carbon tetrach- ?0 loride, agitating and then adding 214.4g of bromine. 310 cm3 of bromine solution are obtained. 3 Into 360 cm of carbon tetrachloride are introduced 24 g of metaphenoxy-toluene and 1.8 g of azo-bis-isobutyro nitrile and the mixture obtained is taken to reflux. 46430 Simultaneously and proportionally over about 2 hours, depending upon the absorption of the bromine indicated by the absence of coloration of the medium, 96g of 3 metaphenoxy-toluene and 240 cm of the bromine sulution prepared above are added thereto. The mixture obtained is subsequently cooled slightly and 1.7g of azo-bis-isobutyro nitrile are added thereto. The resultant mixture is again taken to reflux and, over three to four hours, depending upon the absorption of the bromine, 3 IQ 70 cm of the bromine solution obtained above are added thereto, introducing at the end of two hours 1.7g of azo-bis-isobutyro nitrile. After addition of the bromine solution is complete, the resultant mixture is agitated under reflux for one hour then cooled and concentrated j 5 by distillation under reduced pressure (about 10 torr). 230 g of crude metaphenoxy-benzylidene bromide are obtained (containing 75% of metaphenoxy-benzylidene bromide, which corresponds to a yield of 77% with reference to the metaphenoxy-toluene employed)« 2o By rectification under reduced pressure metaphenoxy- benzylidene bromide of the same purity as the product obtained in Example 1 is obtained„ 4 6 4 3 0 Example 3 Metaphenoxy-benzylidene bromide Operating in a manner similar to that of Example 2 but replacing the azo-bis-isobutyro nitrile with dibenzoyl peroxide, metaphenoxy benzylidene bromide is obtained with the same yield and in the same purity. Example 4 Metaphenoxy-benzylidene chloride 50 g of metaphenoxy-toluene are introduced into 3 500 cm of carbon tetrachloride and the mixture obtained is taken to 70°C .3g of azo-bis-isobutyro nitrile are then added thereto and the resultant mixture is taken to reflux and chlorine is bubbled therethrough so as to fix 35 g of chlorine in about 1 hour 30 minutes. The mixture thus obtained is agitated for 30 minutes under reflux, cooled and concentrated to dryness by distillation under reduced pressure (about 10 torr). 71 g of crude metaphenoxy-benzylidene chloride are obtained titrating 66% of pure dichlorinated derivative (representing a yield of 68% with reference to the metaphenoxy-toluene). The crude product is purified by rectification under reduced pressure. 4 6 4 3 0 Analysis : C13H1()OCl2(253.14) C% H7c Cl% Calculated : 61.66 3<,98 28.0 Found : 61.6 3.9 28.0 Ultra-violet Spectrum: (Ethanol containing 5% water) The spectrum presents aband tail at about the short wave lengths as well as small ;ma'xima at 270 and 279 nm corresponding to a non-conjugated aromatic structure of type the/-f-x (x being other than C or H).

Infra-red Spectrum: (On product per se) Absorptions at 1580cm ^and 1490pm ^ characteristic of the aromatic nuclei, absorptions at 1260cm ^ and 1220cm characteristic of the phenyl-o-p'henyl link.

N.M.Ro Spectrum: (deuterochloroform) Peak at 6.7 ppm (singlet) characteristic of the hydrogen of the CHC^; peaks from 6.8 to 7.7 ppm characteristic of aromatic protons.

Example 5 Metaphenoxy-benzaldehyde Into a solution of 38.8 g of potassium carbonate in 3 800 cm of water is introduced a solution of 80 g of metaphenoxy-benzylidene bromide (crude compound obtained 3 in Example 2) in 800 cm of isopropanol. The mixture obtained is refluxed for five hours, cooled and the 464 30 isopropanol is eliminated by distillation under deduced pressure,, The resultant mixture is extracted with dichloroethane and the organic phase is washed with water, dried and concentrated to dryness by distillation under reduced pressure. 44„62 g of crude metaphenoxy-benzaldehyde are obtained containing 75% of aldehyde, which corresponds to a yield of 77.6% with reference to the metaphenoxy-toluene employed» Example 6 10 Met aph eno xy-benzaldehyde 3 3 Into a mixture of 200 cm of water and 200 cm of dimethylformamide are introduced 200 g of crude metaphenoxy- benzylidene bromide (crude compound obtained in Example 2) and 30 g of a 48% hydrobromic acid solution are added thereto. The mixture obtained is taken to 100°C-105°C for five hours, then cooled and poured into two litres of water. The resultant mixture is extracted with methylene chloride. The extract is dried and concentrated to dryness. 96.3 g of crude metaphenoxy-benzaldehyde are obtained 2o containing 71% of aldehyde, which corresponds to a yield of 74.2% with reference to the metaphenoxy-toluene employed. - 1 6 - 4 6 4 3 0 Example 7 Metaphenoxy-benzaldehyde To the 71 g of crude metaphenoxy-benzylidene chloride 3 3 obtained in Example 4 are added 71 cm of water, 71 cm 3 of dimethylformamide and 7 cm of a 48% hydrobromic acid solution* The mixture obtained is refluxed for 8 hours and then treated as in Example 6. 59.4 g of crude product are obtained titrating 50.5% of aldehyde (that is a yield of 50% with reference to the metaphenoxy-toluene 10 employed)o Example 8 Metaphenoxy-benzaldehyde via its bisulphite To the 230 g of crude metaphenoxy-benzylidene 3 bromide obtained in Example 2 are added 228 cm of 3 3 dimethylformamide, 228 cm of water and 204 cm of 48% hydrobromic acid. The mixture obtained is refluxed (100°C 0 \ Q - 102 C), for 8 hours, then cooled to 50 C and gradually 36° Be sodium hydroxide solution is added thereto until a 3 pH of 6.7 is obtained (about 122 cm )„ 228 g of sodium ; o metabisulphite are then gradually added thereto and the resultant mixture is agitated for 1 hour at 60°C. 240 cm^ of ethyl acetate are subsequently added thereto and the mixture thus formed is refluxed for 1 hour, cooled to 20°C, then agitated1for 1 hour. The precipitate thus formed is 4 6 4 3 0 isolated by vacuum-filtration, washed with salt water then with ethyl acetate and dried. 154 g of metaphenoxy-benzaldehyde bisulphite are obtained titrating 95%, which corresponds to a yield of 74.3% with reference to the metaphenoxy-5 toluene employed.

The 154 g of bisulphite are introduced into a mixture 3 3 of 3080 cm of water, 231 cm of dichlorethane and 35 g of potassium carbonate. The mixture obtained is taken to a temperature of 50°C under nitrogen, and 16»95 g of potassium carbonate are added thereto. The resultant mixture is agitated for 2 hours at 50°C, cooled, and the organic phase is separated off by decanting. The aqueous phase is extracted with dichloroethane. The combined organic phases are washed with water, dried and concentrated to dryness by distillation under reduced pressure. 98.4 g of metaphenoxy-benzaldehyde are obtained.

Example 9 Metaphenoxy-benzaldehyde bisulphite Analogously to Example 8 (hydrolysis in acidic medium 20 in a mixture of water and dimethylforrnamide, . neutralisatiorv purification with ethyl acetate) starting with 71 g of crude metaphenoxy-benzylidyne chloride (obtained in Example 4), 29.2 g of metaphenoxy-benzaldehyde bisulphite are 46<J30 obtained titrating 94% (which corresponds to a yield of 35.6% with reference to the metaphenoxy-toluene employed).

Operating in a manner similar to that of Example 8 the bisulphite obtained above is hydrolysed to yield 18.7 g of metaphenoxy-benzaldehyde»

Claims

4 6 4 3 0 What we claim is:

1. Compounds of general formula I, < / X 0 C - H (I) X of at least 65% by weight. wherein X represents a bromine or chlorine atom having a purity/

2. Metaphenoxy-benzylidene bromide having a purity of at least 65% by weight.

3. Metaphenoxy-benzylidene chloride having a purity of at least 65% by weight.

4. Compounds as claimed in any preceding claim having a purity of from 65 to 85% by weight.

5. Compounds as claimed in any one of claims 1 to 3 in substantially pure form.

6. A compound as claimed in claim 2 having a boiling.,. point of from 152 to 153°c at 0.4 torr.

7. A compound as claimed in claim 2 or claim 6 having a solidification point of + 27.5°C.

8. A process for the preparation of compounds of general formula I as claimed in claim 1 which comprises 20 4 6 4 i reacting metaphenoxy-toluene with chlorine, bromine, N-chloro- or N-bromo-acetamide or N-chloro- or N-bromo-succinimide, at a temperature of from 30 to 150°C and in the presence of a solvent and isolating the compound of formula I thus formed and, if required, purifying said compound of formula I.

9. A process as claimed in claim 8 wherein the reaction is effected at temperatures of from 50 to 120°C„

10. A process as claimed in claims 8 or claim 3 wherein metaphenoxy toluene is reacted with chlorine, bromine or N-bromo-succinimide.

11. A process as claimed in any of claims 8 to 10 wherein the solvent comprises a halogenated aliphatic hydrocarbon containing from 1 to 3 carbon atoms, a monocyclic aromatic hydrocarbon or a cycloalkane.

12. A process as claimed in claim 11 wherein the solvent comprises carbon tetrachloride, carbon tetrabromide, tetrachloroethane, benzene or cyclohexane.

13. A process as claimed in any°o6f claims 8 to 12 wherein the reaction is effected in the presence of a radical initiat or.

14. A process as claimed in claim 13 wherein the radical initiator is a labile azoic compound or a peroxide. - 21 - 4 6 4 3 0

15. A process as claimed in claim 14 wherein the radical initiator is azo-bis-isobutyro nitrile or benzoyl peroxide. one

16. A process as claimed in any/of claims 8 to 15 wherein the compound of formula I formed is purified by rectification.

17. A process for the preparation of metaphenoxy- havinq a purity of at least 65% by weight benzylidene bromide/which comprises reacting metaphenoxy- toluene with N-bromo-succinimide in the presence of azo- bis-isobutyro nitrile and of carbon tetrachloride at the boiling temperature of the reaction mixture, isolating the metaphenoxy-benzylidene bromide thus formed and purifying by rectification.

18. A process for the preparation of metaphenoxy- havina a purity of at least 65% by weight benzylidene bromide/which comprises reacting metaphenoxy- toluene with bromine in the presence of azo-bis-isobutyro nitrile and of carbon tetrachloride at the boiling temperature of the reaction mixture, isolating the metaphenoxy-benzylidene bromide thus formed and purifying by rectification.

19. A process for the preparation of metaphenoxy- having a purity of at least 65% by weight benzylidene chloride/which comprises reacting metaphenoxy- toluene with chlorine in the presence of azo-bis- - 22 - 4643 isobutyro nitrile and of carbon tetrachloride at the boiling temperature of the reaction mixture, isolating the metaphenoxy-benzylidene chloride thus formed and purifying by rectification. one

20. A process as claimed in any/of claims 8 to 19 wherein the metaphenoxy-toluene is reacted with about two equivalents of chlorine, bromine, N-chloro- or N-bromo-acetamide or N-chloro- or N-bromo-succinamide.

21. A process for the preparation of compounds of general formula I as claimed in claim 1 substantially as herein described.

22. A process for the preparation of compounds of general formula I as claimed in claim 1 substantially as one herein described in any/of Examples 1 to

23. Compounds of general formula I as claimed -|n claim 1 one whenaver prepared by a process as claimed in any/of claims 8 to 22.

24. A process for the preparation of metaphenoxy-benzaldehyde which comprises hydrolysing a compound of formula I as claimed in claim 1 in an aqueous medium.

25. A process as claimed in claim 24 wherein the compound of formula I is as claimed in claim 4 or claim 5. - 23 - 4 6 4 3 0

26. A process as claimed in claim 24 or claim 25 wherein the compound of formula I is metaphenoxy-benzylidene bromide.

27. A process as claimed in claim 24 or claim 25 wherein the compound of formula I is metaphenoxy-benzylidene chloride. one

28. A process as claimed in any^of claims 24 to 27 wherein the hydrolysis is effected in the presence of a base.

29. A process as claimed in claim: 27 wherein the base is an alkali metal carbonate.

30- A process as claimed in claim 28 or claim 29 wherein the hydrolysis is effected in the presence of aqueous isopropanol. one

31. A process as claimed in any/of claims 24 to 27 wherein the hydrolysis is effected in the presence of an acid.

32. A process as claimed in claim 31 wherein the acid is hydrobromic acid.

33. A process as claimed in claim 31 or claim 32 wherein the hydrolysis is effected in the presence of aqueous dimethylformamide. one

34. A process as claimed in any/of claims 24 to 33 wherein the metaphenoxy-benzaldehyde is isolated in the form of its - 24 - 46430 bisulphite which is optionally purified and subsequently hydrolysed back to metaphenoxy-benzaldehyde,

35. A process as claimed in claim 34 wherein the metaphenoxy-benzaldehyde is isolated by addition of 5 sodium metabisulphite,

36. A process for the preparation of metaphenoxy-benzaldehyde as claimed in claim 24 substantially as herein described.

37. A process for the preparation of metaphenoxy- one 10 benzaldehyde substantially as herein described in any/of Examples 5 to 9.

38. Metaphenoxy-benzaldehyde whenever prepared by a process as claimed in any of claims 24 to 37. Dated this the 8th day of March, 1978. BY: TOMKINS & KL, Appl iicaritsV wents, (Signed)4—* 5, Dartmouth Road, DUBLIN 6. - 25 -