EP1259472A1

EP1259472A1 - Method for producing chlorocarboxylic acid chlorides

Info

Publication number: EP1259472A1
Application number: EP01909800A
Authority: EP
Inventors: Armin Stamm; Roland Götz; Jochem Henkelmann; Friedrich Closs; Heinz-Josef Kneuper
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2000-03-03
Filing date: 2001-02-28
Publication date: 2002-11-27
Also published as: DE10010594A1; WO2001064613A1; JP2003525260A; AU2001237419A1; CN1407964A; KR20020077932A; HUP0300215A2; CZ20022975A3

Abstract

The invention relates to a method for producing chlorocarboxylic acid chlorides of formula (I), wherein R?1 and R2¿, independently from one another, mean a hydrogen atom, an organic radical containing carbon, a halogen, a nitro or cyano group and Y means an alkylene chain having 1 to 10 carbon atoms in the chain which is unsubstituted or is substituted by organic radicals that contain carbon, by halogen, nitro and/or cyano groups, whereby the alkylene chain can be interrupted by an ether-, thioether-, tertiary amino- or keto group, whereby the organic radicals of Y and/or R1 and/or R2 can be connected to one another and thereby form a non-aromatic system, whereby said radicals contain carbon, by converting a lactone of formula (II), wherein R1, R2 and Y have the aforementioned meanings, using a chlorination means in the presence of a chlorination catalyst and in the presence of a boron compound.

Description

Process for the production of chlorocarboxylic acid chlorides

description

The present invention relates to a process for the preparation of chlorocarboxylic acid chlorides of the formula (I)

Rl \ c -γ_ -c // ° (I)

/ ci-

R2 Cl

in the

R ¹ and R ^{2 are} independent of each other

represent a hydrogen atom, a carbon-containing organic radical, a halogen, a nitro or a cyano group,

and Y

an alkylene chain with 1 to 10 carbon atoms in the chain, which is unsubstituted or substituted by carbon-containing organic radicals, halogen, nitro and / or cyano groups, where the alkylene chain can be interrupted by an ether, thioether, tertiary amino or keto group .

means

the carbon-containing organic radicals of Y and / or R ¹ and / or R ² can be linked to form a non-aromatic system,

by reacting a lactone of the formula (II)

R2

in which R ^X , R ² and Y have the meaning given above, with a chlorinating agent in the presence of a chlorinating catalyst. Chlorocarboxylic acid chlorides are important reactive intermediates for the production of pharmaceutical and agrochemical active ingredients.

Chlorocarboxylic acid chlorides can be prepared, for example, by reacting the corresponding lactones with chlorinating agents in the presence of a catalyst. Typically, phosgene or thionyl chloride is used as the chlorinating agent, since they only form gaseous substances (CO ₂ or SO ₂ and HC1) as by-products.

When using thionyl chloride as the chlorinating agent, zinc chloride is usually used as the catalyst. Appropriate procedures are described in I.I. Grandberg et al. , Izv. Timiryazevsk. S.-kh. Akad. 1974, (6), pages 198 to 204 and O.P. Goel et al., Synthesis, 1973, pages 538 to 539. When converting γ-butyrolactone to 4-chlorobutyric acid chloride, yields of 65 to 80% were achieved.

Various catalyst systems are generally used when phosgene is used as the chlorinating agent. Suitable catalysts include US Pat. No. 2,778,852, pyridines, tertiary amines, heavy metals and acids, such as sulfuric acid, phosphoric acid, phosphorus chloride, phosphorus oxychloride, aluminum chloride, sulfuryl chloride and chlorosulfonic acid. The published patent application DE-A 197 53 773 discloses suitable ones

Catalysts urea compounds, the published documents EP-A 0 413 264 and EP-A 0 435 714 phosphine oxides as well as the published documents EP-A 0 253 214 and EP-A 0 583 589 organic nitrogen compounds, such as quaternary ammonium salts, nitrogen heterocycles, Amines or formamides.

US Pat. No. 2,778,852 describes the synthesis of 4-chlorobutyric acid chloride by reacting γ-butyrolactone with phosgene in the presence of pyridine.

In order to increase the yield, gaseous hydrogen chloride is generally also introduced. However, the use of hydrogen chloride is particularly disadvantageous for ecological and economic reasons, since it is used in excess of stoichiometric amounts and the excess must be worked up and neutralized, which leads to a considerable amount of salt. Furthermore, the use of larger amounts of hydrogen chloride gas requires additional technological and logistical effort. The object was therefore to develop a process for the production of chlorocarboxylic acid chlorides by reacting the corresponding lactones with chlorinating agents which no longer has the known disadvantages and which makes the chlorocarboxylic acid chlorides accessible in high yield and high purity.

Accordingly, a process for the preparation of chlorocarboxylic acid chlorides of the formula (I)

R

in the

R ¹ and R ^{2 are} independent of each other

and Y

means

by reacting a lactone of the formula (II)

in which R ¹ , R ² and Y have the meaning given above, with a chlorinating agent in the presence of a chlorination catalyst, which is characterized in that the reaction is carried out in the presence of a boron compound.

The presence of a boron compound is essential in the process according to the invention. Examples of suitable boron compounds are the compounds and groups of substances listed below, mixtures of different boron compounds also being possible.

Boron oxide, such as B ₂ 0 ₃ .

Boric oxygen acids, such as boric acid (HB0 ₃ , exact name "orthoboric acid"), metaboric acids (of the type HB0 ₂ , for example α-HB0 ₂ , β-HB0 or γ-HB0 ₂ ), oligoboric acids or polyboric acids.

Salts of boric acid such as borates ([B0 ₃ ] ^{3 ~} , exact name "Orthoborat"), oligoborates (e.g. [B ₃ 0 ₃ (OH) ₅ ] ^{2 ~} , [B ₄ 0 ₅ (OH) ₄ ] 2-, [B ₅ 0 ₆ (0H) ₆ ] 3- or [B ₆ 0 ₇ (OH) ₆ ] ^{2 "} ) or polyborates (for example [B0]") with inorganic or organic cations, such as alkali metal ions (for example Li ⁺ , Na ⁺ or K ⁺ ), alkaline earth metal ions (e.g. Mg ²⁺ , Ca ²⁺ or Sr ²⁺ ), ammonium ion NH ⁺ or primary, secondary, tertiary or quaternary amines (e.g. tetra-methylammonium, tetraethylammonium, tetrapropylammonium, tetraisopropylammonium, phenyltrimethylammonium, Phenyltriethylammonium, trimethylammonium, triethylammonium, tripropylammonium, triisopropylammonium, phenyldimethylammonium, phenyldiethylammonium or phenylammonium ("anilinium")).

Boronic acids (RB (OH) ₂ ) and their inorganic or organic salts, such as phenylboronic acid (dihydroxyphenylborane) or disodium phenylboronate.

- Boric acid esters, such as the mono-, di- or tri-Ci-Cg-alkyl esters with the same or different, unbranched or branched alkyl groups (for example methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methyl-propyl, 2-methylpropyl , 1, 1-dimethylethyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2, 2-dimethylpropyl, 1-ethylpropyl, hexyl, 1, 1-dimethylpropyl, 1,2-dirnethylpropyl, 1-methylpentyl, 2 -Methylpentyl, 3-methylpentyl, 4-methylpentyl, 1, 1-dimethylbutyl, 1, 2-dimethylbutyl, 1, 3-dimethylbutyl, 2, 2-dimethylbutyl, 2, 3-dimethylbutyl, 3,3-dimethylbutyl, 1 -Ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1, 2, 2-trimethylpropyl, 1-ethyl-l-methylpropyl or 1-ethyl-2-methylpropyl), for example boric acid methyl ester, boric acid triethyl ester or boric acid tripropyl ester.

Boron halides with fluorine, chlorine, bromine and / or iodine, for example BF ₃ (Bortπf luoπd), BC1 ₃ (Bortπchloπd), BBr ₃ (Bortπbromid), BI ₃ (Bortruodid), BF ₂ C1, BFC1 ₂ , BF ₂ Br, BFBr ₂ , BF ₂ I, BFI ₂ , BFClBr, BFC1I, BFBrI, BCl ₂ Br, BClBr ₂ , BC1 ₂ I, BC1I ₂ , BClBrI, BBr ₂ I, BBrI ₂ , B ₂ F, B ₂ CI ₄ , B ₂ Br ₄ , B ₂ I ₄ and their complexes, for example with oxygen, sulfur or nitrogen compounds, such as hydrates, alcoholates, etherates,

Complexes with sulfides, ammonia, amines or pyπdms, for example [water BF ₃ ], [methanol BF ₃ ], [ethanol BF ₃ ], [dimethyl ether BF], [diethyl ether BF ₃ ], [n-propyl ether BF ₃ ], [isopropyl ether BF ₃ ], [tetrahydrofuran BF ₃ ], [dimethyl sulfide BF ₃ ], [ammonia BF ₃ ], [methylamine BF ₃ ],

[Dimethylamm BF ₃ ], [Tπmethylamm BF ₃ ], [Ethylamm BF ₃ ], [Diethylamm BF ₃ ], [Triethylamm BF ₃ ], [Urea BF ₃ ], [Pyπdm BF ₃ ], [2-Methylpyrιdm BF ₃ ] or [3-methyl-pyπdm BF ₃ ].

Preferably used

Boron oxide B ₂ 0;

Boric acid H ₃ B0 ₃ ;

Borsauretrι-Cι-C alkyl esters, such as Borsauretπ- methyl ester, Borsauretriethylester, Borsauretripropylester, Borsauretrusopropylester or Borsauretributylester;

Bortπfluoπd, Bortrichloπd or their complexes, for example with water, alcohols (in particular methanol), ethers (in particular diethyl ether), sulfides (in particular dimethylsulfide) or amines (in particular ethylamm), for example boron trifluoride dihydrate or boron trifluoride etherates (in particular with diethyl ether),

or their mixtures.

The halogen-free boron compounds boron oxide B ₂ 0 ₃ , boric acid H ₃ B0 ₃ and boric acid C ₁ -C ₄ alkyl ester are particularly preferably used. Particularly preferred is boric acid H ₃ B0 ₃ and boric acid methyl ester. The use of such boron compounds has the advantage that the reaction mixtures are free of fluoride ions. This simplifies the entire apparatus technology compared to the reaction with boron halides. In the process according to the invention, the boron compound or mixtures thereof are / are used in a concentration of 0.1 to 20 mol%, preferably 0.1 to 10 mol%, particularly preferably 0.5 to 5 mol%, based on the lactone (II ) used.

The chlorocarboxylic acid chlorides which can be prepared in the process according to the invention have the formula (I)

in which R ¹ and R ² independently represent a hydrogen atom, a carbon-containing organic radical, a halogen, a nitro or a cyano group.

An organic radical containing carbon is to be understood as an unsubstituted or substituted, aliphatic, aromatic or araliphatic radical having 1 to 20 carbon atoms. This radical can contain one or more heteroatoms, such as oxygen, nitrogen or sulfur, for example - 0-, -S-, -NR-, -CO- and / or -N = in aliphatic or aromatic systems, and / or by one or several functional groups which contain, for example, oxygen, nitrogen, sulfur and / or halogen, such as, for example, fluorine, chlorine, bromine, iodine and / or a cyano group. If the carbon-containing organic radical contains one or more heteroatoms, this can also be bound via a heteroatom. Thus, for example, ether, thioether and tertiary amino groups are also included. Preferred examples of the carbon-containing organic radical are C 1 -C ₂ -alkyl, in particular Cχ-Cς-alkyl, Cζ- to Cio-aryl, C ₇ - to C ₂ o ^-Ar alk l, in particular C - to Cio Aralkyl, and C - to C ₂ o-alkaryl, in particular C ₇ - to Cio-alkaryl.

Halogens are fluorine, chlorine, bromine and iodine.

To Cιo ~ aralkyl or C ₇ - - chlorine carboxylic acid chlorides (I) in which R ¹ and R ² independently of one another are hydrogen, ^~ to C alkyl, Cg to Cio-aryl, C ₇ are preferred to Cio alkaryl mean for example methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1, 1-dimethylethyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2, 2 -Dimethylpropyl, 1-ethyl-propyl, hexyl, 1, 1-dimethylpropyl, 1, 2-dimethylpropyl, 1-methyl-pentyl, 2-methylpentyl, 3-methyipentyl, 4-methylpentyl, 1, 1-dimethylbutyl, 1, 2-dimethylbutyl, 1, 3-dimethylbutyl, 2,2-dimethylbutyl, 2, 3-dimethylbutyl, 3, 3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1, 1, 2-trimethylpropyl, 1, 2, 2-trimethyl-propyl, 1-ethyl- l-methylpropyl, l-ethyl-2-methylpropyl, phenyl, 2-methylphenyl (o-toluoyl), 3-methylphenyl (m-toluoyl), 4-methylphenyl (p-toluoyl), naphthyl or benzyl. Hydrogen and C ₄ to C ₄ alkyl, in particular hydrogen, are particularly preferred.

Y represents an unsubstituted or carbon-containing organic radicals, halogen, nitro and / or cyano groups substituted alkylene chain with 1 to 10 carbon atoms of the chain, the alkylene chain being replaced by an ether (-0-), thioether- (-S-), tertiary amino (-NR-) or keto group (-CO-) may be interrupted. The carbon-containing organic residues and halogens smd as defined above.

Examples of the radical Y are the alkylenes (CH ₂ ) _n with n equal to 1 to 10, one or more, optionally all of the hydrogen atoms being from C 1 to C 8 alkyl, C 1 to C 10 aryl, C ₇ to Cio Aralkyl and / or C ₇ to C 10 alkaryl, for example methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1, 1-dimethylethyl, pentyl, 1-methylbutyl, 2- Methylbutyl, 3-methylbutyl, 2, 2-dimethylpropyl, 1-ethylpropyl, hexyl, 1, 1-dimethylpropyl, 1, 2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1, 1- Dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1, 1,2-trimethylpropyl, 1, 2, 2-tπmethylpropyl, 1-ethyl-l-methylpropyl, l-ethyl-2-methylpropyl, phenyl, 2-methylphenyl (o-toluoyl), 3-methylphenyl (m-toluoyl), 4- Methylphenyl (p-toluoyl), naphthyl or benzyl can be replaced.

Preferred are the chlorocarboxylic acid chlorides (I) in which Y is an unsubstituted alkylene (CH ₂ ) _n ^{m nt} n is 2 to 8, particularly preferably n is 2 to 4, specifically CH ₂ CH ₂ , CH ₂ CH ₂ CH ₂ , CH ₂ CH ₂ CH ₂ CH ₂ .

It is also possible that the organic radicals R ¹ and / or R ² and / or of Y are bonded together to form a non-aromatic system. An example of this is hexahydrophthalide.

The chlorocarboxylic acid chlorides (I) which are very particularly preferred in the process according to the invention are 4-chlorobutyric acid chloride (4-chlorobutanoic acid chloride), 5-chlorovaleric acid chloride (5-chloropentanoic acid chloride) or 6-chlorocaproacetic acid chloride (6-chlorohexanoic acid chloride). The lactones to be used have the formula (II)

in which R ¹ , R ² and Y have the meanings given above. Mixtures of different lactones can of course also be used. Γ-Butyrolactone, δ-valerolactone or ε-caprolactone are very particularly preferably used.

The chlorinating agents used are preferably phosgene, diphosgene (trichloromethyl chloroformate), triphosgene (bis (trichloromethyl) ester) and / or thionyl chloride. The use of phosgene or thionyl chloride, in particular gaseous and / or liquid phosgene, is particularly preferred.

In principle, all known chlorination catalysts, in particular nitrogen and phosphorus compounds, are suitable as chlorination catalysts, such as, for example, open-chain or cyclic, unsubstituted or substituted ureas, N, N-di-substituted formamides (for example N, N-dimethylformamide), trialkyl or unsubstituted or Substituted triarylphosphine oxides, substituted or unsubstituted pyridines, quaternary ammonium salts (eg benzyltrimethylammonium chloride), amidines or their salts including hydrochlorides, unsubstituted or mono- to poly-substituted guanidines or hexaalkylguanidinium salts.

A urea compound, a phosphine oxide, a pyridine compound or mixtures thereof is preferably used as the chlorination catalyst.

The urea compounds used with preference are described, for example, in the published patent application DE-A 197 53 773. Open-chain, substituted urea compounds of the formula (III) are particularly preferably used.

X

^R3 ^ N ^ N ^{/ R6} , (TITI _T I ₁ ),

I I

R4 R5 where X is oxygen or sulfur and R ³ to R ⁵ independently of one another are preferably C ₁ -C 8 -alkyl or in which one of the radicals R ³ or R ⁴ together with one of the radicals R ⁵ or R ^{6 is} a C ₂ - to C ₄ ~ alkylene chain means. Urea compounds which are liquid under reaction conditions are very particularly preferred, for example N, N '-dimethylethylene-urea (1, 3-dimethyl-2-imidazolidinone), N, N' -dirnethylpropylene-urea (1, 3-dimethyltetrahydro- 2 (1H) -pyrimidinone), N, N, N ', N'-tetrabutylurea or N, N, N', N '-tetramethylthiourea. The urea compounds mentioned can be used as such or in the form of their salts with hydrochloric acid, for example as hydrochlorides, or in the form of their salts of the Vilsmeier type obtainable by reaction with phosgene, the hydrochlorides being preferred.

The preferred phosphine oxides are described, for example, in the published patent application EP-A 0 413 264. The trialkyl or unsubstituted or substituted triarylphosphine oxides of the formula (IV) are particularly preferably used.

0 R7-P-R9 _{{IV) #} R8

where R ⁷ to R ⁹ independently of one another are preferably C 1 -C 10 -alkyl or unsubstituted or substituted by C 1 -C ₄ -alkyl. Phosphine oxides which are liquid under reaction conditions are very particularly preferred, for example linear or branched trioctyl, trihexyl or tributylphosphine oxide and triphenylphosphine oxide or mixtures of various trialkylphosphine oxides (for example Cyanex from Cytec Industries).

The preferred substituted or unsubstituted pyridines are represented by the formula (V)

in which R ¹⁰ to R ¹⁴ independently of one another preferably denote hydrogen or Cχ ~ to C ₄ alkyl. It is also possible that two adjacent residues form a non- aromatic or aromatic system are interconnected. The mono-C 1 -C ₄ -alkylpyridines are particularly preferred, very particularly preferably the monomethylpyridines, in particular 3-methylpyridine (β-picoline).

In the process according to the invention, 3-methylpyridine, triphenylphosphine oxide and / or trialkylphosphine oxide are used in particular.

Above all, the use of liquid chlorination catalysts has process engineering advantages. For example, the time-consuming handling of solids and their dosing and conveying are eliminated. In addition, a much more fluid bottom discharge is obtained in the subsequent distillative workup and blockages are avoided.

The chlorination catalyst is used in the process according to the invention in a concentration of 0.1 to 20 mol%, preferably 0.1 to 10 mol%, particularly preferably 0.5 to 5 mol%, based on the lactone (II).

In a further preferred form of the process, the catalyst is used in the form of a complex of the boron compound and the chlorination catalyst. This can be produced, for example, by joining the two components before or in the reactor. Suitable complexes are, for example, the BF-β-picoline complex.

In principle, the apparatuses for gas / liquid and liquid / liquid reactions described in the relevant specialist literature can be used as reactors for the chlorination. In order to achieve a high space / time yield, intensive mixing between the solution containing lactone, chlorination catalyst and boron compound and the chlorinating agent added is important. Non-restrictive examples include stirred tanks, stirred tank cascades, countercurrent reaction columns, flow tubes (preferably with internals), bubble columns and loop reactors.

The process is preferably carried out without a solvent. However, it is possible to add a solvent which is inert to the chlorinating agent used. Inert solvents are, for example, aromatic hydrocarbons, such as toluene, chlorobenzene, o-, m- or p-dichlorobenzene, o-, m- or p-xylene, cyclic carbonates, such as ethylene carbonate or propylene carbonate, the corresponding chlorocarboxylic acid chloride target product or mixtures thereof , If solvents are used, this is preferred Chlorocarboxylic acid chloride target product used. The addition of a solvent can be advantageous, for example, when using high molecular weight, viscous or solid lactones (II) under reaction conditions.

The process according to the invention can be carried out at a temperature of 50 to 200 ° C., preferably 80 to 200 ° C., particularly preferably 110 to 160 ° C. It generally takes place at a pressure of 0.01 to 5 MPa abs, preferably 0.5 to 2 MPa abs, ms - especially at atmospheric pressure.

The total amount of phosgene added in the process according to the invention is generally 0.8 to 1.5 mol, preferably 0.9 to 1.2 mol, per mol of lactone (II).

The starting materials (lactone (II) and chlorinating agent) and the catalysts (chlorination catalyst and boron compound) can generally be added in any order. The lactone (II), the chlorination catalyst, the boron compound and, if appropriate, a solvent are preferably introduced to one variant and the chlorinating agent is subsequently introduced or, in another variant, all the components are supplied simultaneously. Embodiments which lie between the two variants are of course also possible and, if appropriate, advantageous.

When the starting materials and catalysts are available, it is also possible to bring various components in front of or in contact with the reactor. For example, an upstream formation of a complex from the boron compound and the chlorination catalyst is possible (e.g. BF -ß-Pιcolm complex). Furthermore, an upstream reaction between the chlorination catalyst and the chlorinating agent is also possible (e.g. Vilsmeier salt made from N, N-dialkylformamide and phosgene or thionyl chloride).

The method according to the invention can be carried out batchwise or continuously.

a) discontinuously

In the batchwise preparation, the reaction mixture containing the lactone (II), the chlorination catalyst, the boron compound and, if appropriate, a solvent in general is initially introduced into a reaction apparatus, for example a Ruhr kettle, and mixed intensively. Now the desired amount of liquid or gaseous chlorination is at the desired temperature and pressure medium added. After the addition of chlorinating agent has ended, the reaction solution is allowed to react for a few minutes to a few hours. The after-reaction can take place in the reaction apparatus or in a downstream vessel.

In a special variant of the batch process, the liquid chlorinating agent (e.g. thionyl chloride), optionally with the chlorination catalyst and / or the boron compound and / or a solvent, can also be introduced. The lactone (II) is then, optionally with the

Chlorination catalyst and / or the boron compound and / or a solvent, added at the desired temperature and pressure over a certain period of time.

b) continuously

Reaction apparatuses suitable for the continuous process, for example Ruhr kettles, Ruhr kettle cascades or reaction columns operated in countercurrent. At the start of the continuous process, a solvent (e.g. the corresponding chlorocarboxylic acid target product), the chlorination catalyst and the boron compound are generally introduced, the system is brought to the desired temperature and liquid or gaseous chlorinating agent is added. Subsequently, parallel to the continuous supply of the chlorinating agent, the continuous introduction of lactone (II), which generally contains further chlorination catalyst and further boron compound and can optionally be dissolved in a solvent, is started. After the reactor contents have reacted to form chlorocarboxylic acid chloride, the amounts of lactone (II) and chlorinating agent are adjusted in such a way that both are supplied essentially with water. A quantity of the reaction volume corresponding to the quantity fed in is withdrawn from the reaction apparatus, for example via maintenance or through an overflow. The reaction solution is preferably fed to a further vessel for the after-reaction.

It is generally advantageous to subsequently expel unreacted chlorinating agent, for example by passing a gas which is chemically inert to the reaction solution, such as nitrogen, from the reaction solution (“stripping”). Unreacted chlorinating agent which, for example, already escapes from the reactor during the synthesis stage and / or which is expelled by subsequent "stripping", can advantageously be collected and used again. Suitable collecting devices, for example cooling traps, to which the chlorinating agent condenses.

The reaction solution resulting from the reaction between the lactone (II) and the chlorinating agent can be worked up using the public methods. Preference is given to working up by distillation, in which case the optional “stripping” can take place before or in the distillation column.

It is possible and possibly advantageous to recycle all or part of the bottom product obtained in the work-up by distillation, which contains, inter alia, the chlorination catalyst and the boron compound. Of course, a further work-up of the surf discharge, for example a distillative removal of the chlorination catalyst and / or the boron compound, can also take place before the recycling. If the process is carried out with recycling of the chlorination catalyst and / or the boron compound, it is advantageous to recycle only a part of the possible by-products and to replace the other part with fresh catalysts.

In a general embodiment for the batchwise production of chlorocarboxylic acid chlorides (I), the entire amount of the corresponding lactone (II), the preferably liquid chlorination catalyst, the boron compound and, if appropriate, a solvent (for example the corresponding chlorocarboxylic acid chloride product) are placed in a Ruhr kettle. The reaction system is now brought to the desired temperature and liquid and / or gaseous phosgene or liquid thionyl chloride is fed continuously at atmospheric pressure with further vigorous stirring. The gaseous co-products formed, carbon dioxide or sulfur dioxide, and hydrogen chloride are removed. After the desired amount of chlorinating agent has been added, the reaction solution is left for a while at the set temperature with continued stirring for post-reaction. In the after-reaction, chlorinating agent still present in the reaction solution is reacted with residual lactone (II). In order to remove or remove the excess chlorinating agent and its reaction products carbon dioxide or sulfur dioxide as well as hydrogen chloride from the reaction solution, it is possible to pass inert gas through with intensive mixing (“stripping”). The reaction solution obtained is then fed to the workup. In general, the processing by distillation, if necessary under vacuum. In the case of high molecular weight chlorocarboxylic acid chlorides, other cleaning processes, such as crystallization, are also possible

In a general embodiment for the continuous production of chlorocaroonic acid chlorides (I), the reactor, e.g. a Ruhr kettle, a solvent (e.g. the corresponding chlorocarboxylic acid chlor_d cell product), the chlorination catalyst and the boron compound, brings the system to the desired temperature and adds f_jssιges or gaseous chlorinating agent. Then, parallel to the continuous supply of the chlorinating agent, the mixture is degassed with the continuous introduction of lactone (II), which generally contains further chlorinating catalyst and / or other boron compound and, if appropriate, can be dissolved in a solvent. After the contents of the reactor have converted to chlorocarboxylic acid chloride, the amounts of lactone (II) and chlorinating agent are adjusted in such a way that both are fed essentially in an equimolar amount. A quantity of the reaction volume corresponding to the quantity fed in is removed from the reaction apparatus, for example via a maintenance or an overflow. The reaction solution withdrawn is collected in a downstream container, for example a Ruhr kettle, for the subsequent reaction. After the downstream container has also been filled by the reaction discharge, the overflow is possibly from the by-products carbon dioxide and

Hydrogen chloride as exempt described Oden and Aufarbei ^¬ tung fed. The workup can be carried out, for example, by distillation.

The process according to the invention enables chlorocarboxylic acid chlorides to be prepared by reacting the corresponding lactones with a chlorinating agent which makes the chlorocarboxylic acid chlorides accessible in high yield and high purity and no longer has the disadvantages of additionally introducing hydrogen chloride gas. The chlorocarboxylic acid chlorides can be easily separated from the boron compounds added according to the invention during workup.

Examples

experimental arrangement

The experimental set-up comprised a 1 1 double-walled glass vessel with a stirrer, thermostatting, an conduit for the gaseous or liquid chlorinating agent and a two-part cooler cascade. The two-part cooler cascade comprises an intensive cooler, which was heated to -10 ° C, and one Carbonic acid cooler, which was tempered to -78 ° C. The tests were carried out at atmospheric pressure.

Example 1 (according to the invention)

200 g of δ-valerolactone (2.0 mol), 9.3 g of β-picolm (3-methylpyπdm, 0.1 mol) and 3.1 g of boric acid (0.05 mol) were placed in a double-walled glass vessel. With vigorous stirring, a total of 229 g of gaseous phosgene (2.32 mol) were introduced at 144 to 148 ° C. in the course of 5 hours. The system was then left for a further hour without the addition of phosgene for the after-reaction. After stripping out the remaining, unreacted phosgene with nitrogen, a crude output of 310 g was obtained. The raw discharge was fractionally distilled at 0.7 kPa abs (7 mbar abs) and 70 to 75 ° C. 255 g of 5-chlorovaleric acid chloride with a purity of> 98 GC area% were isolated. This corresponds to a yield of 82%.

Example 2 (according to the invention)

172 g of γ-butyrolactone (2.0 mol), 9.3 g of β-picolm (3-methylpyrιdm, 0.1 mol) and 3.1 g of boric acid (0.05 mol) were placed in a double-jacketed glass vessel and made up to 140 ° C warmed. With vigorous stirring, a total of 242 g of gaseous phosgene (2.45 mol) were introduced at 140 to 147 ° C within 4 hours and 15 minutes. The system was then left for a further hour without phosgene for the subsequent reaction. After stripping out the remaining, unreacted phosgene with nitrogen at 100 ° C., a crude discharge of 289 g was obtained. The raw discharge contained 93.6 GC area% 4-chlorobutyric acid chloride.

Example 3 (according to the invention)

172 g of γ-butyrolactone (2 mol), 34.8 g Cyanex 923 ^® (. Commercial product of Cytec Industries, a mixture of various Trialkylphosphi - noxide mol with an average molecular weight of 348 g / mol, 0.1) and 3.1 g Boric acid (0.05 mol) was placed in a double-jacketed glass vessel. With vigorous stirring, a total of 251 g of gaseous phosgene (2.54 mol) were introduced at 144 to 148 ° C. in the course of 5 hours and 20 minutes. The system was then left for a further hour without phosgene for the subsequent reaction. After stripping out the remaining, unreacted phosgene with nitrogen at 100 ° C. within 7 hours, a crude discharge of 314 g was obtained. The raw output was fractionally distilled at 5.1 kPa abs (51 mbar abs) and 87 ° C. There were 242 g of 4-chlorobutyric acid chloride with a purity of 15

> 99 GC area% isolated. D it corresponds to a yield of

86%.

Example 4 (According to the Invention)

200 g of δ-valerolactone (2.0 mol), 9.3 g of β-picolm (3-methylpyrιdm, 0.1 mol) and 5.2 g of trimethyl borate (0.05 mol) were placed in a double-walled glass vessel and made up to 140 ° C warmed. Under stirring 242 g tensivem in ^¬ gasformi ges phosgene (2.45 mol) were introduced at 140 to 146 ° C as a whole. The system was then left for a further hour without any phosgene feed. After stripping out the remaining, unreacted phosgene with nitrogen at 100 ° C., a crude discharge of 318 g was obtained. The raw output was fractionally distilled at 0.9 kPa abs (9 mbar abs) and 75 to 77 ° C. After a preliminary run of 10 g, which already contained 96.6 GC area% 5-chlorovaleric acid chloride, a pure fraction of 256 g was obtained. It contained 98.2 GC area% 5-chloro-valerine acid chloride. The overall yield after distillation was 85%.

Example 5 (according to the invention)

10 g of δ-valerolactone (0.1 mol), 1.14 g of benzyltrimethylammonium chloride πd (0.006 mol) and 0.31 g of boric acid (0.005 mol) were placed in a double-jacketed glass vessel. With vigorous stirring, a total of 15.5 g of liquid thionyl chloride (0.13 mol) were introduced at 120 to 125 ° C. within 7 hours. The system was then left for a further hour without the addition of thionyl chloride. The reaction discharge contained 70 GC area% 5-chlorovaleric acid chloride and 7 GC area% unreacted δ-valerolactone.

Example 6 (comparative example)

192 g of γ-butyrolactone (2.23 mol) and 2 g of pyride (0.025 mol) were placed in a double-jacketed glass vessel and heated to 120 ° C. With vigorous stirring, a total of 60 g of gaseous phosgene (0.61 mol) were introduced at 120 to 124 ° C within 8 hours. After stripping out the remaining, unreacted phosgene with nitrogen, the crude product was fractionally distilled. The first fraction with 76 g contained 21.6 GC area% 4-chlorine butter - acid chloride, the second fraction with 110 g 2.6 GC area% 4-chlorobutane acid chloride. This corresponds to an overall yield of 6%. Comparative Example 6 shows that in the absence of boron compounds and without the introduction of hydrogen chloride only a Unzu ^¬ reaching yield can be achieved.

Claims

claims

1. Process for the preparation of chlorocarboxylic acid chlorides of the formula (I)

Rl .0

// cci — Y — c (i:

R2 Cl

in the

R ¹ and R ^{2 are} independent of each other

th is a hydrogen atom, a carbon-containing organic radical, a halogen, a nitro or a cyano group signified ^¬,

and Y

an alkylene chain with 1 to 10 carbon atoms in the chain, which is unsubstituted or substituted by carbon-containing organic radicals, halogen, nitro and / or cyano groups, the alkylene chain being substituted by an ether,

Thioether, tertiary amino or keto group can be interrupted,

means

wherein the carbon-containing organic radicals of Y and / or R ¹ and / or R ² can be linked to one another to form a non-aromatic system, by reacting a lactone of the formula (II)

in which R ¹ , R ² and Y have the meaning given above, with a chlorinating agent in the presence of a chlorination catalyst, characterized in that the reaction is carried out in the presence of a boron compound.

2. The method according to claim 1, characterized in that the boron compound used is boron trifluoro, boron chloride or their complexes, boron oxide, boric acid, a boric acid C 1 -C ₄ alkyl ester or mixtures of at least two of these boron compounds.

3. Process according to claims 1 to 2, characterized in that the boron compound is used in a concentration of 0.1 to 20 mol% based on the lactone (II).

4. Process according to claims 1 to 3, characterized in that phosgene, diphosgene, Tπ- phosgene and / or thionyl chloride are used as chlorinating agents.

5. Process according to claims 1 to 4, characterized in that a urea compound, e phosphine oxide, a pyride compound or mixtures thereof is used as the chlorination catalyst.

6. The method according to claim 5, characterized in that 3-methylpyπdm, Tπphenyl-phosph oxide and / or Tπalkylphosphmoxid is used as the chlorination catalyst.

7. Process according to claims 1 to 6, characterized in that the chlorination catalyst is used in a concentration of 0.1 to 20 mol% based on the lactone (II).

8. The method according to claims 1 to 7, characterized in that one. Chlorination catalyst and the boron compound in the form of a complex of both components.

9. The method according to claims 1 to 8, characterized in that the reaction at a temperature of 50 to

200 ° C and a pressure of 0.01 to 5 MPa abs.

10. The method according to claims 1 to 9, characterized in that the lactone (II) used is γ-butyrolactone, δ-valerolactone or ε-caprolactone.