Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
  • C07C45/42—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by hydrolysis
  • C07C45/43—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by hydrolysis of >CX2 groups, X being halogen
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/58—Preparation of carboxylic acid halides
  • C07C51/60—Preparation of carboxylic acid halides by conversion of carboxylic acids or their anhydrides or esters, lactones, salts into halides with the same carboxylic acid part

Definitions

• the invention relates to a process for preparing chlorides of benzene acids and aldehydes.
• Acid chlorides are important synthesis intermediates in the chemical industry. They are widely used for the synthesis of various pharmaceutical products (antiviral, anti-inflammatory agents) or phytosanitary products (herbicides, insecticides). They are also used for the synthesis of peroxides which are in particular used as initiators for radical polymerizations.
• the main routes of access to acid chlorides include processes which react conventional reagents such as phosgene, sulfonyl chloride, phosphorus tri- or pentachlorides and thionyl chloride.
• the POCI 3 and the pivaloyl chloride obtained have temperatures so close (1 04-1 06 ° C) that it is almost impossible to separate them.
• reaction is carried out in the presence of a molar excess of 20% to 50% of SOCI 2 .
• molar yields of distilled acid chlorides are obtained, for example around 90%.
• catalysts such as DMF, pyridine or N-methylacetamide makes it possible to increase the reaction kinetics and improve the selectivity (lowering the percentage of secondary products such as anhydride).
• SOCI 2 has the disadvantage of leading to acid chlorides which may contain sulfur.
• a catalyst in the event that a catalyst is used, its recycling is difficult.
• the acid chlorides can also be obtained from phosgene according to the reaction:
• the chlorides of aliphatic and aromatic acids can be obtained simultaneously by reaction of an aromatic compound containing at least one residue -CCI 3 linked to an aromatic carbon with an aliphatic carboxylic acid in the presence of catalysts such as H 2 SO 4 (US 4 , 1 63,753) H 3 PO 4 , HCIO 4 (US 1, 965,556) FeCI 3 or ZnCI 2 (FR 2,686,601).
• catalysts such as H 2 SO 4 (US 4 , 1 63,753) H 3 PO 4 , HCIO 4 (US 1, 965,556) FeCI 3 or ZnCI 2 (FR 2,686,601).
• Benzene aldehydes and in particular benzaldehyde are used in perfumery and as intermediates for the synthesis of various chemicals (dyes, antibiotics).
• the access routes to benzene aldehydes, in particular benzaldehyde include processes which constitute the hydrolysis of the corresponding dichloromethylated benzene compounds.
• benzaldehyde is obtained industrially by hydrolysis, acid or alkaline, of benzylidene chloride according to the reaction:
• the acids used are in particular H 3 PO 4 , mentioned in the patent application (FR 21 6 374), HCI (DE 2 756 61 2) and HCO 2 H (EP 41 672).
• Sulfuric acid has also been used, but has the drawback of leading to discharges which consist of dilute solutions of H 2 SO 4 .
• H 2 SO 4 has been used for the hydrolysis of certain substituted benzylidene chlorides such as 2,4- and 2,6-dichloro-1 - (dichloromethyl) benzenes.
• Benzaldehyde can also be obtained by partial oxidation of toluene.
• a process is described which consists in partially oxidizing toluene in the liquid phase at temperatures between 10 ° C. and 200 ° C. under pressures ranging from 2 to 50 bars in the presence of catalysts based on Co and Mn.
• C 6 H 5 CHCI 2 can react with one mole of acetic acid in the presence of
• Example 1 6 the preparation of benzaldehyde and propionyl chloride by reacting, with stirring, at 100 ° C for 1 h 30, 0.5 mole of chloride benzylidene and 0.5 mole of propionic acid in the presence of 0.005 mole of SnCI 4 .
• the Applicant has carried out batch tests to reproduce the methods of the prior art described above. It obtained conversions and low yields and found the presence of significant quantities of secondary products, which in particular contain cinnamic acid derivatives in the case of the reaction with acetic acid (or its anhydride) and, in a manner general, along with the other 15 acids, aromatic diesters such as benzylidene dicarboxylates
• R represents an alkyl radical, linear or branched, having a number of carbon atoms ranging from 1 to 1 2 and, preferably, ranging from 1 to 8, optionally substituted by 1 or more halogen atoms such as Cl, Br, F; an alkenyl radical having a number of carbon atoms ranging from 2 to 8, optionally substituted by 1 or more halogen atoms such as Cl, F; a phenyl radical optionally substituted by one or more atoms of Cl, Br or F, by a linear or branched alkyl residue, having a number of carbon atoms ranging from 1 to 4, said residue possibly containing 1 or more halogen atoms such as Cl, Br, F; (R 1 ) TM denotes that the benzene nucleus may have one or more substituents, identical or different, chosen from the group consisting of a Cl atom, a Br atom, an F atom, an alkyl radical, linear or branched, having a number of carbon
• the total or partial fractional distillation of the reaction medium can be carried out separately in a fractional distillation installation.
• the contents of the reactor where the reaction was carried out is transferred, in whole or in part, to said distillation installation.
• the non-transferred part serves as the base for a subsequent operation.
• the base stock mainly comprises dichloromethylated benzene compound (2) as well as a defined proportion of catalyst. It can also comprise, in small amounts, acid chloride and / or benzene aldehyde originating from a previous operation, in particular intermediate sections of fractional distillation of the reaction medium.
• the base stock represents at most 30% by volume of the reactor used for the implementation of the process.
• dichloromethylated benzene compound (2) and the carboxylic acid (1) or its anhydride (1 a) in a molar ratio (2) / (1) or (2) / (1 a) ranging from 1 / n to 1.2 / n and preferably ranging from 1 / n to 1.05 / n.
• the term “Friedel and Crafts type catalyst” is used to denote a Lewis acid or a Bronsted acid.
• Lewis acid which can be used according to the invention
• FeCl 3 ZnCI 2 , SbCI 5 , CoCI 2 , BiCl 3 , ZrCI 4
• ZnCI 2 or FeCI 3 will be used
• Brônsted acid which can be used according to the present invention
• sulfuric acid phosphoric acid.
• Friedel and Crafts type catalysts can be introduced into the reaction zone as such or in the form of aqueous solutions or in solution in one of the reactants.
• a molar amount of pure Lewis acid of between 0.01% and 2% and, preferably, between 0.05% and 0.5% relative to the amount of the dichloromethylated compound will be used ( 2) implementation.
• a molar amount of pure Brnsted acid of between 0.1% and 5% and preferably between 0.5% and 2%, relative to the amount of the dichloromethylated compound (2 ) implemented.
• the present invention applies very particularly well to carboxylic acids (1) or to their anhydrides (1 a) having the carbon in ⁇ of CO (carbonyl) as substituted as possible.
• carboxylic acids (1) or to their anhydrides (1 a) having the carbon in ⁇ of CO (carbonyl) as substituted as possible By way of illustration of such acids, mention will be made of isobutyric, pivalic, 2-chloropropionic, trifluoroacetic, trichloroacetic acids.
• the invention also applies well to benzoic acid or its substituted derivatives.
• the process of the invention is particularly applicable to the preparation of acid chlorides having the most substituted CO carbon at ⁇ and benzaldehyde from benzylidene chloride and the preferred carboxylic acids (or their anhydrides) mentioned above.
• the hydrogen chloride formed in the case where a carboxylic acid (1) is used, can be washed against the current with the dichloromethylated benzene compound (2) in order to recover any acid chlorides entrained .
• the HCI recovered is advantageously absorbed in water in a slaughter column to lead to aqueous solutions of very pure commercial HCI.
• the organic washing solution can be reused for synthesis.
• the process has the advantage of leading to acid chlorides and to benzenic aldehydes of high purity and of constant quality with high yields and selectivities.
• This process also has the advantage of generating little or no secondary products, no gaseous effluents in the case where an acid anhydride is used as reagent or else generates HCI which can be recovered in the form of commercial solutions. when using a carboxylic acid.
• this process also has the advantage of not using volatile catalysts which would be entrained practically continuously during the extraction of the products, which would generate pollution of the products and loss of activity during the reaction stage.
• the reaction is carried out in batch in a glass reactor of
• the mixture, with stirring, is gradually heated to 105 ° C. over 30 min and then kept at this temperature for 2 h 30 (until the evolution of HCl is stopped).
• the poor selectivity for pivaloyl chloride corresponds to the formation of benzylidene pivalate C 6 H 5 CH [OC (O) C (CH 3 ) 2 ] 2 identified by CPG / S coupling.
• the reaction is carried out semi-continuously in a 500 ml glass flask surmounted by an Oldershaw type distillation column with 10 theoretical plates.
• the column head equipped with a reflux timer is connected to two dual circulation refrigerants to condense and recover the organics in a first recipe.
• the refrigerant outlet is connected to a line of vents including a dry ice trap (second recipe) followed by a water washer to absorb the HCl.
• the reagents have been previously mixed to obtain a stock solution (maintained at a temperature below 25 ° C.) which can then be introduced into the reactor using a single metering pump at a flow rate of 80 ml / h.
• the start of the release of HCI is observed from the start of the introduction of the reagents and this release continues at a flow rate of between 0.3 and 0.4 mol / h.
• the pivaloyl chloride begins to condense at the head of the column after approximately 1 hour 30 minutes of introduction, it is then withdrawn continuously with an average flow rate of the order of 25 g / h. At the end of the introduction of the reagents, the total quantity of HCI absorbed corresponds to 102.5% of the theoretical quantity.
• the mass of pivaloyl chloride extracted is 1 34.6 g (of which 1 1 8, 1 g in the first recipe and 1 6.5 g in the second recipe) with a purity of 97.6%, which represents a yield of 43.6%.
• the reaction crude remaining in the flask is then distilled under reduced pressure (from 500 to 50 mbar) and one thus obtains:
• the reaction is carried out in an assembly similar to that of Example 2 but the synthesis step is carried out under reduced pressure and with a molar excess of benzylidene chloride of 5.6% relative to pivalic acid.
• the vacuum is ensured by a membrane pump (all Teflon) connected to the line of vents at the outlet of the dry ice trap and the outlet of which is connected to the water washer to absorb the HCl.
• a membrane pump all Teflon
• This base stock is brought to a temperature of 120 ° C., with stirring and under pressure of 180 mbar. While maintaining the temperature at 120 ° C., 206 g (2 mol) of pivalic acid, 236.4 g (1, 432 mol) of benzylidene chloride and 391 mg (2.9) are then introduced continuously by gravity. mmol) of ZnCI 2 in 5 h, the rate of introduction of the mixture, adjusted using a micrometric valve, is 80 ml / hour. The start of the release of HCI is observed from the start of the introduction of the reagents and this release continues at an average flow rate of 0.4 mol / h.
• the pivaloyl chloride begins to condense at the head of the column after approximately 30 min of introduction, it is then withdrawn continuously with an average flow rate of the order of 45 g / h.
• the total amount of HCI absorbed corresponds to 97.5% of the theoretical amount.
• the mass of pivaloyl chloride extracted is 224.7 g (of which 1 61.8 g in the first recipe and
• reaction crude remaining in the flask is then distilled under reduced pressure (at 150 mbar) and one thus obtains:
• the reaction is carried out according to a process analogous to that of Example 3 but by reaction of benzylidene chloride with isobutyric acid (example 4), isobutyric anhydride (examples 5 and 6) and 2-chloropropionic acid (example 7).
• the purity of the benzylidene chloride used is between 97% and 99%.
• the catalyst used is ZnCl 2 with a molar ratio of 0.2% relative to the benzylidene chloride, except in Example 4 where the molar ratio is only 0.1%.
• Table 2 indicates the respective conversions of the reagents, the yields of acid chloride extracted simultaneously with the supply of said reagents, the overall molar yields of acid chloride and the yields of benzaldehyde obtained after distillation under reduced pressure at the bottom. reaction.

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• Organic Chemistry (AREA)
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• Oil, Petroleum & Natural Gas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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Citations (4)

• 1999
  • 1999-09-10 FR FR9911354A patent/FR2798380B1/fr not_active Expired - Fee Related
• 2000
  • 2000-09-07 WO PCT/FR2000/002467 patent/WO2001019766A1/fr not_active Application Discontinuation
  • 2000-09-07 EP EP00960819A patent/EP1210310A1/de not_active Withdrawn
  • 2000-09-07 BR BR0013925-4A patent/BR0013925A/pt not_active Application Discontinuation
  • 2000-09-07 JP JP2001523347A patent/JP2003509391A/ja not_active Withdrawn
  • 2000-09-07 KR KR1020027003121A patent/KR20020041428A/ko not_active Application Discontinuation
  • 2000-09-07 AU AU72997/00A patent/AU7299700A/en not_active Abandoned

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