FR2510989A1 - Aromatic haloformate(s) from aromatic alcohol(s) or phenol(s) - by reaction with carbonic di:halide e.g. benzyl tri:phenyl phosphonium chloride - Google Patents

Abstract

Prodn. of aromatic haloformates comprises: (a) reacting a carbonic dihalide (such as phosgene or bromophosgene) with an aromatic alcohol or phenol in the presence of a quat. phosphonium salt based catalyst, where the anion of the quat. phosphonium salt is a halide or the anion of the aromatic alcohol. The reaction is effected under anhydrous conditions and at a temp. of 60deg.C up to the temp. at which a substantial amt. of carbonate is formed; and (b) removal of the formed hydrogen halide from the reaction mixt. The aromatic haloformates have numerous uses, but are partic. useful as carbamate-type pesticide and herbicide intermediates. The present invention yields the haloformates in goodyields, keeping the formation of aromatic carbonate to a min.

Description

 The present invention relates to a process for the preparation of aromatic haloformate.

 When a carbonic dihalogenide and an aromatic alcohol are reacted to form an aromatic haloformate there is a considerable tendency for the formation of aromatic carbonate. Such aromatic carbonate formation represents a loss of yield to the desired aromatic haloformate and is, therefore, undesirable.

 The present invention relates to a process for obtaining an aromatic haloformate while maintaining the formation of aromatic carbonate at low levels.

Accordingly, the present invention relates to a process for the production of aromatic haloformate which comprises a) reacting, under substantially anhydrous conditions and at a temperature ranging from about 60 ° C. to the temperature at which carbonate is formed in significant amounts. , a carbonic dihalide and an aromatic alcohol in the presence of a quaternary phosphonium salt as a catalyst where the anion of the quaternary phosphonium salt is a halide or anion of the aromatic alcohol and b) to remove the halide of hydrogen from the vicinity of the reaction medium.

 In general, both reactants are ultimately introduced into the reaction zone in equivalents. Although an excess of either reagent can be used, it is usually preferable to use a slight excess of carbonic dihedral.

Usually, the carbonic dihalide equivalent ratio to the finally introduced aromatic alcohol is from about 0.9: 1 to about 1.5: 1. About 1: 1 to about 1.2: 1 is preferred.

 Examples of carbon dihalides that can be used include phosgene, bromophosgene and bromochlorophosgene. The preferred carbonic dihalide is phosgene. It is possible to use only a carbonic dihalogen or, where appropriate, a mixture of carbon dihalides.

 As aromatic alcohols which can be used for the purposes of the invention, it is possible to dimension in particular monofunctional and polytonchalonic aromatic alcohols.

The aromatic alcohol may be unsubstituted or may be substituted by any of the various substituents which do not seriously interfere with the halogenoformate generating reaction. Examples of substituents which may be used are alkyls containing 1 to 4 carbon atoms. about 4 carbon atoms, haloalkyl containing 1 to about 4 carbon atoms, cycloalkyl of 3 to about 5 carbon atoms, cycloalkyl substituted by halo groups, containing from 3 to about 8 carbon atoms, alkoxy and the like. substituted alkoxy having 1 to about 4 carbon atoms in the alkyl part, halo, nitro and cyan groups. When two hydroxyl groups are present on the same aromatic ring, they must be located on non-adjacent carbon atoms. The aromatic alcohol may contain a plurality of aromatic rings joined by carbon-carbon bonds, alkylidene groups, sulphone bonds or other small linking groups which are stable under the reaction conditions used in the described haloformate formation process. in the present description.

 Examples of aromatic alcohols which may be used are phenol, 4-chlorophenol, 2-chlorophenol, 4-bromophenol, 2,4-dichlorophenol, 2,5-dichlorophenol, 2,4,6-dichlorophenol, triphenophenol, 3-nitrophenol, 2-ethylphenol, 2-isopropoxyphenol, 2-chloro-3-nitrophenol, 2-butylphenol, 2,4-xylenol, 2- (trichloromethyl) phenol, 4- cyclohexylphenol, 4- (4-chlorocyclohexyl) phenol, 2,4-dinitro-6-sec-hutylphenol, 1-naphthol, 4-chloro-1-naphthol, 2-naphthol, 6-chloro-2-naphthol, hydroquinone , 2,7-dihydroxynaphthalene, 4,6-dimethyl-2,7-dihydroxynaphthalene, 4,6-dinitro-2,7-dihydroxynaphthalene, p, p'-biphenol, o, o ' biphenol, o, p'-biphenol, m, me-biphenol, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (2 , 6-dichloro-4-hydroxyphemyl) propane, 2,2-bis (2,6-dibromo-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone and bis (2-methyl-4-hydroxyphenyl) sulfone S Either an aromatic alcohol or a mixture of aromatic alcohols may, if desired, be used.

 The quaternary phosphonium salts that can be used as catalysts in the present invention vary widely. Such catalysts may contain only one phosphonium salt group or may contain more than one phosphonium salt group.

dans laquelle R1, R2, R3 et R4 sont chacun indépendamment un alkyle non substitué, un alkyle substitué, un phényle non substitué, un phényle substitué, un phénylalkyle non substitué ou un phénylalkyle substitué. Lorsquton utilise des groupes substitués, ceux-ci devront être tels qu'ils ne perturbent pas sérieusement la fonction du catalyseur. Les divers groupes
R1, R2, R3 et R4 peuvent être tous identiques, certains peuvent être identiques ou tous peuvent être différents. L'anion, AO peut être un halogénure ou il peut être l'anion de l'alcool aromatique devant être converti en haloformiate aromatique.A subclass of quaternary phosphonium salt which is of particular interest in the invention is that represented by the formula

wherein R1, R2, R3 and R4 are each independently unsubstituted alkyl, substituted alkyl, unsubstituted phenyl, substituted phenyl, unsubstituted phenylalkyl or substituted phenylalkyl. When using substituted groups, these should be such that they do not seriously disturb the function of the catalyst. The various groups
R1, R2, R3 and R4 may all be the same, some may be the same or all may be different. The anion, AO may be a halide or it may be the anion of the aromatic alcohol to be converted to aromatic haloformate.

The latter comes from the removal of the hydrogen atom from a hydroxyl group of the aromatic alcohol. Usually, unsubstituted alkyl groups and substituted alkyl groups each contain 1 to about 16 carbon atoms, with 1 to about 4 carbon atoms being preferred. Particularly preferred unsubstituted alkyl groups are methyl, ethyl, propyl, isopropyl and butyl. Of the substituted halo substituted alkyl groups, the alkyl is preferably a halogen-substituted alkyl may contain one or more than one halo substituent. Typically, the halo substituents are chloro or bromo. Substituents of substituted phenyl groups are usually halo or lower alkyl. Preferred substituted phenyl groups are monohalophenyl and dihalophenyl wherein the halo substituents are fluoro, chloro or bromo.

The alkyl portion of the unsubstituted phenylalkyl and substituted phenylalkyl generally contains from 1 to about 4 carbon atoms.

Another subclass of quaternary phosphonium salts that can be used is that represented by Formula I wherein R 1 and R 2 are linked to form and be part of a ring containing up to about 8 atoms in the ring, including 1 phosphorus atom and in which R3,
R4 and A are as previously described.

dans laquelle Ar est un groupe aromatique, tel que par exemple un phényle non substitué ou substitué ou un groupe aromatique provenant de l'élimination d'un groupe hydroxyle de l'alcool aromatique devant etre converti en halogénoformiate aromatique et dans laquelle R1, R2, R3 et A sont tels que décrits auparavant à.propos de la formule I.Yet another subclass of quaternary phosphonium salts which is useful is that represented by the structure

wherein Ar is an aromatic group, such as, for example, unsubstituted or substituted phenyl or an aromatic group derived from the removal of a hydroxyl group from the aromatic alcohol to be converted to the aromatic haloformate and wherein R1, R2, R3 and A are as previously described in Formula I.

Another subclass of useful quaternary phosphonium salts is that represented by Formula I or Formula II in which one or more of the groups
R1, R2, R3 and, in the case of formula I, R4 represents a polymeric support. Suitable polymeric carriers include silica polymer and styrene polymer.

See, for example, P. Tundo, "Silica Gel as a Polymeric Support for Phase-transfer Catalysts", Journal of the Chemical Society
Chemical Communications, 1977, pp. 641-642 and SL Regen et al., "Liquid-Solid-Liquid Triphase Catalysis ..."
Journal of the American Chemist Society (July 1979), Vol. 101, pages 4059-4063, both of which are hereby incorporated by reference. A quaternary phosphonium group or more than one quaternary phosphonium group may be attached to the polymeric support.

Another subclass of phosphorium salts
Useful quaternary is where more than one quaternary phosphonium group is attached to a stable multivalent organic group.

dans laquelle Q est un groupe organique multivalent stable,
R2, R3 et A - sont tels que décrits auparavant à propos de la formule I et de la formule II, R5 est R4 de la formule I ou -0-Ar de la formule II et n est la valence de Q.This subclass can be represented by the formula

wherein Q is a stable multivalent organic group,
R2, R3 and A - are as previously described with respect to formula I and formula II, R5 is R4 of formula I or -O-Ar of formula II and n is the valence of Q.

 Types of other subclasses of quaternary phosphonium salts in which the organic groups attached to the phosphorus atom of the phosphonium group are stable and do not interfere with the formation of the haloformate.

aromatic, can be used in the invention.

Examples of satisfactory quaternary phosphonium salts are
tetrabutylphosphonium bromide (hexadecyl) trimethylphosphonium chloride
benzyl bromide (tris (trifluoromethyl) phospho
minium
bromide (16-chlorohexadecyl) tripentylphosphonium
(methyl) (phenyl) (phenoxy) benzyl chloride
phosphonium
tris (4-butylphenyl) methylphosphonium chloride
tris (butylbenzyl) phosphonium bromide
tris (4-phenylbutyl) dodecylphosphonium chloride
bemzyltriethylphosphonium chloride
(2-phenylethyl) tripropylphosphonium chloride
benzyltriisopropyl phosphonium chloride
(2,4-dichlorophenyl) tributylphosphoric acid
Phonium
butylphenylphosphonium bromide
benzyltriphenylphosphonium chloride
(3-bromopropyl) triphenylphosphonium bromide
(chloromethyl) triphenylphosphonium chloride
cyclopropyltriphenylphosphonium bromide
ethyltriphenylphosphonium bromide
(methoxymethyl) triphenylphosphonium chloride
the bromide of. methyltriphenylphosphonium
propyltriphenylphosphonium bromide
(Phemoxy) triphenylphosphonium chloride
tetramethylenediphenylphosphonium chloride
(o-isopropoxyphenyl) triphenylphos chloride
Phonium
p-xylylenebis bromide (triphenylphosphonium)
It is possible to use a quaternary phosphonium salt or a mixture of quaternary phosphonium salts.

Phosphonium salts. quaternary compounds for the purpose of the invention are those of formula I in which R1,
R2, R3 are all unsubstituted phenyl groups and R4. is either unsubstituted alkyl containing 1 to 4 carbon atoms or benzoyl. Particularly preferred are benzyltriphenylphosphonium chloride and benzyltriphenylphosphonium bromide.

 The quaternary phosphonium salt catalyst may itself be introduced into the process or a precursor of the quaternary phosphonium salt catalyst may be introduced.

dans laquelle R1, R2 et R3 sont tels que décrits plus haut à propos de la formule I.Bien que l'on ne désire pas être lié par une quelconque théorie, on pense que la conversion peut être représentée comme suit

auquel cas l'oxyde de phosphine tertiaire réagit d'abord avec un dihalogénure carbonique pour former un dihalogénure de phosphine trisubstitué et du dioxyde de carbone et le dihalogénure de phosphine trisubstitué réagit ensuite avec l'alcool aromatique pour former l'halogémure de phosphonium quaternaire de la formule II. Dans les réactions ci-dessus, chaque X représente, selon le cas, un groupe halogéno ou un halogénure et ils peuvent être identiques ou différents selon le dihalogénure carbonique utilisé ; ArOH représente un alcool aromatique et R1, R2 et R3 sont tels que décrits à propos de la formule I.One type of precursor that can be used is a compound that is not a quaternary phosphonium salt, but that is converted to the quaternary phosphonium salt catalyst in the reaction medium. An example of this type of precursor is a tertiary phosphine oxide represented by the structure

wherein R 1, R 2 and R 3 are as previously described with respect to formula I. Although it is not desired to be bound by any theory, it is believed that the conversion can be represented as follows

in which case the tertiary phosphine oxide reacts first with a carbonic dihalide to form a trisubstituted phosphine dihalide and carbon dioxide and the trisubstituted phosphine dihalide then reacts with the aromatic alcohol to form the quaternary phosphonium halide. formula II. In the above reactions, each X represents, as the case may be, a halogeno group or a halide and they may be identical or different depending on the carbonic dihalide used; ArOH represents an aromatic alcohol and R1, R2 and R3 are as described with respect to Formula I.

An example of a precursor of this type is triphenylphosphine oxide.

 Another type of precursor that can be used is a quaternary phosphonium salt in which at least one of the organic groups is converted to a different organic group in the reaction medium. Examples of these precursors include allyltriphenylphosphonium halide and vinyltriphenylphosphonium halide in which the unsaturated groups are hydrohalogenated to haloalkyl groups.

 Another type of precursor still capable of being used is a quaternary phosphonium salt in which the anion, which is other than a halide or anion of an aromatic alcohol, is replaced in the reaction medium by a halide or the anion of an aromatic alcohol. An example of a precursor of this type is benzyltriphenylphosphonium nitrate.

 Although the various types of precursors have been described individually, it is appreciated that the precursor may share the characteristics of more than one type as exemplified by vinyltriphenylphosphonium nitrate. Also, although the precursors have been shown to be converted to monofunctional quaternary phosphonium salts used in the invention, it is evident that the principles are applicable to precursors that are transformed into compounds having more than one group of quaternary phosphonium salt.

 The amount of quaternary phosphonium salt catalyst that can be used in the invention is subject to wide variations. In general, the amount is a catalytic amount, that is, an amount sufficient to catalyze the haloformate formation reaction. From purely chemical considerations, there is probably no theoretical limit greater than the amount of quaternary phosphonium salt used but practical considerations, such as the need to assemble the reagents and the catalyst in a reasonable volume and the desire to separate the catalyst from the product, suggest that the amount of salt used is at least approximately the amount appropriate to achieve the desired results. In liquid phase reactions, the equivalent ratio of the quaternary phosphonium salt to the aromatic alcohol before ultimately, the conversion is generally from about 0.001: 1 to about 0.5: 1. About 0.005: 1 and about 0.1: 1 are preferred.

However, in vapor phase reactions, the ratio can be very low since a considerable amount of aromatic alcohol vapor can be passed over the catalyst.

In carrying out the reaction, it is preferred that acid acceptors, such as sodium hydroxide, sodium carbonate and the like are substantially absent. Although small quantities can be
present, the quantity must be such that it does not interfere
markedly the use of hydrogen halide to
from the vicinity of the reaction medium.

The actual reaction can be carried out in
continuous or discontinuous, discontinuous reactions being more common. We can leave the hydrogen halide
accumulate in the vicinity of the reaction medium and remove it at a later stage or it can be removed continuously or semi-continuously.

The manner in which the carbondihalide, the aromatic alcohol and the catalyst for the reaction are combined under substantially anhydrous conditions can be varied within wide limits. For example, a vapor phase reaction in which carbonic dihalide vapor and alcohol vapor are passed may be used. aromatic over the catalyst. A batch operation can be used in which the aromatic alcohol is in a liquid phase with the dissolved catalyst and to which the carbonic dihalide is added. In a variant of this process, the catalytic amount of the catalyst is suspended in the liquid aromatic alcohol which is added carbonic dihalide. The carbonic dihalide and the aromatic alcohol can be introduced continuously or intermittently into a reaction mixture containing the catalyst. The haloformate can be allowed to accumulate in the reaction mixture or it can
the case, be eliminated, continuously or semi-continuously.

If necessary, additional catalyst can be added.

In liquid phase operations, it is preferable, if the aromatic alcohol is a solid, to prepare
first a liquid mass of haloyenoformate product
preformed containing a catalytic amount of the catalyst
form of suspension or solution, then introduce
in the mass of molten or solid aromatic alcohol and to add
the carbonic dihalide either during or after the addition
aromatic reaction.The reaction is advantageously
performed in such a way that the carbon dihalide is continuously passed into the reaction mixture while the unreacted carbonic dihalide and the hydrogen halide are removed. The carbon dihalide removed from the reaction mixture can be easily condensed and reintroduced into the reaction mixture while the more volatile hydrogen halide is removed from the system. By carrying out the reaction in this preferred manner, a stoichiometric deficit of carbonic dihalogenide relative to aromatic alcohol is maintained in the liquid phase reaction mixture until approximately the end of the reaction after substantially all of the aromatic alcohol. This means that the ratio of carbon dioxide equivalents to aromatic alcohol is in the liquid phase of the reaction zone below the ratio of stoichiometric equivalents over most of the reaction.

Unless modified by the addition of additional amounts of aromatic alcohol, the ratio increases during the reaction as the conversion of the aromatic alcohol increases. The carbonic dihalide to aromatic alcohol equivalent ratio present in the liquid phase of the reaction mixture is preferably from about 0.01: 1 to about 0.95: 1 until 80% conversion of the aromatic alcohol. After completion of the reaction, it is generally advantageous to remove the residual carbonic dihalide by blowing nitrogen or other suitable gas or by reducing the pressure sufficiently to cause the residual carbonic dihalide to distill off.

 One of the advantages of the invention is that the process can be carried out in the absence of an inert solvent. However, when the aromatic alcohol is a solid, it may be desirable to use an inert solvent in which the aromatic alcohol dissolves and wherein the carbonic dihalide, the aromatic alcohol and the catalyst react to form an aromatic haloformate.

 In fact, any solvent or solvent mixture may be used as long as they are inert to the reactants and reaction products at and below the reaction temperature. Examples of suitable solvents are aromatic hydrocarbon solvents, such as benzene, toluene and xylene. Chlorinated aliphatic solvents, such as methylene chloride, chloroform, carbon tetrachloride, trichlorethylene and perchlorethylene may be used. Similarly, chlorinated aromatic solvents such as chlorobenzene, o-dichlorobenzene and o-chlorotoluene are useful. The preferred inert solvents are toluene and xylene.

 The weight ratio of inert solvent / dissolved solids used is subject to a large variation. In general, the amount of solvent should be sufficient to solvate the reactants and the aromatic halogenoformate product at the reaction temperature. The weight ratio of inert solvent to dissolved solids is usually from about 0.5: 1 to about 100: 1. About 1: 1 to about 3: 1 is preferred.

 When a reaction in the liquid phase is used, the reaction mixture is generally stirred, for example by stirring.

 Although the process can be conducted at a temperature in the range of about 600 ° C to the temperature at which carbonate is formed in a substantial amount, the generally useful temperature range is from about 600 ° C to about 2000 ° C. The preferred temperature range is from about 800 ° C to about 1600 ° C. The expression "temperature at which carbonate is formed in a substantial amount" refers to the temperature above 600 ° C at which the ratio, in equivalents, of aromatic carbonate produced to the aromatic haloformate produced has increased to about 0, 15: 1.

 The reaction is generally conducted at atmospheric pressure although higher or lower pressures may be used if desired.

 In many cases, depending on the amounts and identities of the substances present in the liquid phase reaction mixture, the quaternary phosphonium salt precipitated from the reaction mixture in the liquid phase when the aromatic alcohol concentration is reduced below the level. necessary for complete solubilization of the quaternary phosphonium salt. Frequently, the haloformate is obtained with a high degree of purity by simple extraction of the quaternary phosphonium salt precipitated from the liquid phase. In such circumstances, additional processing steps, such as distillation, recrystallization and the like that purify the product, can often be omitted. However, these additional processing steps may be used as desired. The precipitated quaternary phosphonium salt recovered may be reused as such or washed before reuse. Examples of suitable substances which can be used for washing are hexane, heptane, benzene, toluene, xylene, cyclohexane, methylene chloride, ethylene dichloride, chlorobenzene and other substances. wherein the aromatic haloformate is soluble but wherein the quaternary phosphonium salt is relatively insoluble.

 The aromatic haloformates produced by the process of the invention find many uses.

They are particularly useful as intermediates in the production of pesticides and herbicides, particularly those of the carbamate type.

 In the following illustrative examples, all parts are in parts by weight and all percentages by weight unless otherwise indicated. The reactions are carried out under substantially anhydrous conditions.

EXAMPLE 1
In a 250 ml three-neck round bottom flask equipped with magnetic stir bar, thermometer, dip tube for phosgene, isopropamol-cooled reflux condenser and snow carbonic and an electric heating cap, 76.1 g of o-isopropoxyphenol is charged with 90.9% purity (0.431 mol) and 3.89 g (0.01 mol) of benzyltriphenylphosphonium chloride. The charged materials are heated with stirring to 1180C. As the temperature increases, the benzyltriphenylphosphonium chloride dissolves. During a period of 50 minutes while the temperature is between 1180 ° C. and 15 ° C., 58.5 g (0.59 mol) of phosgene are added. During the course of the reaction, the hydrogen chloride evolved escapes through the condenser.

Benzyltriphenylphosphonium chloride begins to precipitate from the liquid phase toward the end of the conversion of o-isopropoxyphenol. After the end of the addition, the reaction mixture is stirred for a further 50 minutes while the excess phosgene reflux and the temperature is between 1350C and 1410C. The mixture is degassed under vacuum and cooled. The precipitated benzyltriphenylphosphonium chloride is separated from the liquid phase by filtration. The an-alyce by gas-liquid chromatography shows that the filtrate contains 86.5% of o-isopropoxyphenyl chloroformate and less than 0.05% of bis-isopropoxyphenyl carbonate).

The yield of o-isopropoxyphenyl chloroformate is 97.1% relative to the o-isopropoxyphenol charged. After washing the precipitate with cyclohexane and drying, the recovery of benzyltriphenylphosphonium chloride is estimated at 93.3%.

EXAMPLE II
In a 250 ml three-necked round-bottom flask, 75.3 mg (0.501 mol) of 2-sec-butylphenol and -3.89 g (0.1 mol) of benzyltriphenylphosphonium chloride are charged. The charged materials are heated with stirring at 1240C.

Benzyltriphenylphosphonium chloride dissolves as the temperature increases. Over a period of 100 minutes, while the temperature is between 1240C and 1500C, 62.5 g (0.632 mol) of phosgene are added. During the reaction, the evolved hydrogen chloride escapes through the condenser. Benzyltriphenylphosphonium chloride begins to precipitate from the liquid phase near the end of the conversion of 2-sec-butylphenol. After completion of the addition, the reaction mixture is stirred for a further 30 minutes while the excess phosgene refluxes and the temperature is maintained at about 1500 ° C.

The mixture is degassed under vacuum and cooled. The precipitated benzyltriphenylphosphonium chloride is separated from the liquid phase by filtration. Analysis by gas-liquid chromatography shows that the filtrate contains 99.0% of 2-sec-butylphenyl chloroformate, 0.7 parts of bis (2-secbutylphenyl) carbonate and 0.1% of 2-sec-butylphenol. . The yield of 2-sec-butylphenyl chloroformate is 95.4% relative to the charged 2-sec-butylphenol. After washing the precipitate with toluene and drying, the recovery of benzyltriphenylphosphonium chloride is evaluated at 97.7%. The benzyltriphenylphosphonium chloride recovered is not distinguished by infrared spectroscopy, initially charged benzyltriphenylphosphonium chloride.

EXAMPLE III
In a 250 ml three-neck round bottom flask equipped as in Example I, 94.3 g (1.002 mol) of phenol and 7.78 g (0.02 mol) of benzyltriphenylphosphonium chloride are charged. The charged materials are heated with stirring to 1330C. Benzyltriphenylphosphonium chloride dissolves as temperature increases. Over a period of 3.5 hours, while the temperature is between 1330C and 1530C, phosgene is added in excess. During the reaction, the evolved hydrogen chloride escapes through the condenser. Benzyltriphenylphosphonium chloride. begins to precipitate from the liquid phase almost at the end of the phenol conversion. After the end of the addition, the reaction mixture is stirred for an additional 30 minutes while the excess phosgene refluxes and the temperature is maintained in the limits of 145 to 1500C. The mixture is degassed under vacuum and cooled. The precipitated benzyltriphenylphosphonium chloride is separated from the liquid phase by filtration. Analysis by gas-liquid chromatography shows that the filtrate contains 88.4% of phenyl chloroformate, 10.9% of diphenyl carbonate and 0.7% of phenol. The yield of phenyl chloroformate is 82.0% with respect to the charged phenol. After washing the precipitate with n-hexane and drying, the recovery of benzyltriphenylphosphonium chloride is evaluated at 93.2%. The benzyltriphenylphosphonium chloride recovered is not distinguished by infrared spectroscopy, benzyltriphenylphosphonium chloride loaded initially.

EXAMPLE IV
In a 250 ml three-necked round bottom flask equipped as in Example I, 47.1 g (0.50 mole) of phenol and 3.88 g (0.01 mole) of benzyltriphenylphosphonium chloride are charged.
The charged materials are heated with stirring to 1290C. Benzyltriphenylphosphonium chloride dissolves as temperature increases. Over a period of 2 hours, while the temperature is between 123 and 1410e, 69 g (0.70 mol) of phosgene are added. During the reaction, the evolved hydrogen chloride escapes through the condenser. The benzyltriphenylphosphonium chloride begins to precipitate from the liquid phase near the end of the phenol conversion. After completion of the addition, the reaction mixture is stirred for an additional 20 minutes while the excess phosgene refluxes and the temperature increases. is kept within the limits of 131 to 137 c.

The mixture is degassed under vacuum and cooled. The precipitated benzyltriphenylphosphonium chloride is separated from the liquid phase by filtration. The analysis by gas chromatography shows that the filtrate contains 96.4% of phenyl chloroformate, 3.4% of diphenyl carbonate and 0.2% of phenol. The yield of chloroformate diphenyl is 91.8% based on the phenol charged. After washing the precipitate and drying, the recovery of benzyltriphenylphosphonium chloride is evaluated at 90.3%
EXAMPLE V
In a 250 ml three-neck round bottom flask equipped as in Example I, 48.7 g (0.517 mol) of phenol are charged. It does not charge phosphonium salt. The charged phenol is heated under stirring to 970C. Over a period of 30 minutes, while the temperature is in the range of 97 to 1530C, 17.5 g (0.177 mol) of phosgene are added. An accumulation of phosgene is observed so that no additional addition of phosgene is made. During the reaction, the evolved hydrogen chloride escapes through the condenser. After completion of the addition, the reaction mixture is stirred for a further 12.1 hours while the phosgene refluxes and the temperature is maintained within 1480C to 1600C. The reaction mixture is degassed with a stream of nitrogen. and cooled. Analysis by gas-liquid chromatography shows that the liquid contains 8.0% of phenyl chloroformate, 11.4% of diphenyl carbonate and 80.7% of phenol. The yield of phenyl chloroformate is 4.5%. compared to the charged phenol.

EXAMPLE VI
In a 250 ml three-neck round bottom flask equipped as in Example I, 47.0 g (0.499 mol) of phenol and 2.78 g (0.01 mol) of triphenylphosphine oxide are charged.

The charged materials are heated with stirring to 1370C. The triphenylphosphine oxide dissolves as the temperature increases. Over a period of 2 hours, while the temperature is between 1340C and 1390 C, is added 64 g (0.65 mole) of phosgene. During the reaction, the hydrogen chloride escapes through the condenser. After completion of the addition, the reaction mixture is stirred for a further 15 minutes while the excess phosgene refluxes and the temperature is maintained at about 1390C. No precipitation of solid is observed. The mixture is degassed under vacuum and cooled. Analysis by gas-liquid chromatography shows that the liquid contains 97.2% phenyl chloroformate, 2.7% diphenyl carbonate and 0.1% phenol. The yield of phenyl chloroformate is 91.8% based on the phenol charged.

est obtenue de S.L. Regen de Marquette University. La préparation de cette résine de polystyrène à base de phosphonium est décrite par S.L. Regen et 3.s. Besse, "Liquid-Solid-Liquid
Triphase Catalysis..." Journal of the American Chemical
Society, (juillet 1979), volume 101, pages 4059-4063.EXAMPLE VII
Phosphonium-based polystyrene resin which is polystyrene crosslinked with 1% divinylbenzene wherein 17% of the phenyl groups are substituted by a group represented by the formula:

is obtained from SL Regen of Marquette University. The preparation of this phosphonium-based polystyrene resin is described by SL Regen and 3.s. Besse, "Liquid-Solid-Liquid
Triphase Catalysis ... "Journal of the American Chemical
Society, (July 1979), Volume 101, pages 4059-4063.

 In a 250 ml three-necked round bottom flask equipped as in Example I, 47.2 g (0.502 mol) of phenol and 4.32 g (0.005 mol of phosphonium groups) of the polystyrene phosphonium above. The charged materials are heated with stirring to 1430C.

During a period of 3 hours, while the temperature is between 133 and 143 ° C., 66 g (0.67 mol) of phosgene are added. During the reaction, the liberated hydrogen chloride is released by the condenser. After the addition is complete, the reaction mixture is stirred for an additional 25 minutes while the excess phosgene refluxes and the temperature is maintained within the range of 136 to 1390C.

The mixture is degassed under vacuum and cooled. The phosphonium-based polystyrene resin is separated from the liquid phase by filtration. Analysis by gas-liquid chromatography shows that the filtrate contains 97% phenyl chloroformate, 3.0% diphenyl carbonate and less than 0.05% phenol. The yield of phenyl chloroformate is 91.8% based on the phenol charged. After washing, solids separated with toluene and drying, the recovery of the phosphonium-based polystyrene resin is evaluated at 97.5%.

 Although the present invention has been described with reference to specific details of some of its embodiments, there is no question that these details are considered as limitations to the scope of the invention insofar as they are included. in the appended claims.

Claims (18)

 1. Process for the production of aromatic haloformate consisting in that it consists  a) reacting, under substantially anhydrous conditions and at a temperature in the range of about 600 ° C. To the temperature at which carbonate is formed in a substantial amount, a carbonic dihalogenide and an aromatic alcohol in the presence of a catalyst quaternary phosphonium salt base wherein the anion of said quaternary phosphonium salt is a halide or anion of said aromatic alcohol, and  b) removing the hydrogen halide from the vicinity of the reaction mixture.  2. Method according to claim 1, characterized in that said quaternary phosphonium salt is represented by the formula

 in which  a) R1, R2, R3 and R4 are each independently unsubstituted alkyl, substituted alkyl, unsubstituted phenyl, substituted phenyl, unsubstituted phenylalkyl or substituted phenylalkyl; and  b) i is said anion of said quaternary phosphonium salt.  3. Method according to claim 2, characterized in that  a) said unsubstituted alkyl and said substituted alkyl each contain 1 to about 16 carbon atoms, and  b) the alkyl portion of said unsubstituted phenylalkyl and said substituted phenylalkyl contains 1 to about 4 carbon atoms.  4. Process according to claim 3, characterized in that said unsubstituted alkyl and said substituted alkyl each contain 1 to about 4 carbon atoms.  5. Process according to claim 2, characterized in that R1, R2 and R3 are all unsubstituted phenyl and R4 is unsubstituted alkyl containing 1 to 4 carbon atoms or benzyl.  6. Process according to claim 1, characterized in that said quaternary phosphonium salt is represented by the formula:

 in which  a) R 1, R 2, R 3 are each independently unsubstituted allyl, substituted allyl, unsubstituted phenyl, substituted phenyl, unsubstituted phenylalkyl or substituted phenylalkyl  b) Ar is an aromatic group; and c) A <) is said anion of said quaternary phosphonium salt.  7. Method according to claim 6, characterized in that  a) said unsubstituted alkyl and said substituted alkyl each contain 1 to about 16 carbon atoms and  b) that the alkyl portion of said unsubstituted phenylalkyl and said substituted phenylalkyl contains from 1 to about 4 carbon atoms.  8. Process according to claim 7, characterized in that said unsubstituted alkyl and said substituted alkyl each contain 1 to about 4 carbon atoms.  9. Process according to claim 6, characterized in that Ar is unsubstituted phenyl or substituted phenyl.  10. Process according to claim 6, characterized in that Ar arises from the removal of a hydroxide group from said aromatic alcohol.  he. Method according to claim 1, characterized  in that said quaternary phosphonium salt is benzyltriphenylphosphonium chloride or benzyltriphenylphosphonium bromide.  12. The method of claim 1, characterized in that said carbonic dihalide is phosgene or bromophosgene.  13. The method of claim 1, characterized in that said temperature is between about 600C and about 2000C.  14. The method of claim 1, characterized in that said temperature is between about 800C and about 1600C.  15. The method of claim 1, characterized in that said aromatic alcohol is a monofunctional aromatic alcohol.  16. Process according to claim 1, characterized in that the reaction is a reaction in the liquid phase.  17. The method of claim 16, characterized in that said reaction is carried out batchwise.  18. The method of claim 16, characterized in that the quaternary phosphonium salt precipitates from the reaction mixture in the liquid phase.  19. Process according to claim 18, characterized in that said precipitated quaternary phosphonium salt is recovered.