Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C245/00—Compounds containing chains of at least two nitrogen atoms with at least one nitrogen-to-nitrogen multiple bond
  • C07C245/12—Diazo compounds, i.e. compounds having the free valencies of >N2 groups attached to the same carbon atom
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C245/00—Compounds containing chains of at least two nitrogen atoms with at least one nitrogen-to-nitrogen multiple bond
  • C07C245/02—Azo compounds, i.e. compounds having the free valencies of —N=N— groups attached to different atoms, e.g. diazohydroxides
  • C07C245/04—Azo compounds, i.e. compounds having the free valencies of —N=N— groups attached to different atoms, e.g. diazohydroxides with nitrogen atoms of azo groups bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C257/00—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines
  • C07C257/04—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines without replacement of the other oxygen atom of the carboxyl group, e.g. imino-ethers
  • C07C257/06—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines without replacement of the other oxygen atom of the carboxyl group, e.g. imino-ethers having carbon atoms of imino-carboxyl groups bound to hydrogen atoms, to acyclic carbon atoms, or to carbon atoms of rings other than six-membered aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C257/00—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines
  • C07C257/10—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines with replacement of the other oxygen atom of the carboxyl group by nitrogen atoms, e.g. amidines
  • C07C257/14—Compounds containing carboxyl groups, the doubly-bound oxygen atom of a carboxyl group being replaced by a doubly-bound nitrogen atom, this nitrogen atom not being further bound to an oxygen atom, e.g. imino-ethers, amidines with replacement of the other oxygen atom of the carboxyl group by nitrogen atoms, e.g. amidines having carbon atoms of amidino groups bound to acyclic carbon atoms

Definitions

• the subject of the present invention is a process for the preparation of azoiminoethers (in the form of hydrochloride) and their hydrolysis into esters of azocarboxylic acids, these esters thus prepared being useful as a free radical initiator in polymerization reactions.
• the present invention also relates to the mixed azoiminoethers thus prepared as well as the mixed esters of azocarboxylic acids derived therefrom.
• the preparation of the azocarboxylic acid esters is conventionally carried out by a two-stage process comprising a first stage of conversion of the azonitrile, by reaction with an alcohol, in the presence of HCl, according to the Pinner reaction, leading to the hydrochloride of corresponding azoiminoether and a second hydrolysis step in the presence of water of the hydrochloride thus obtained.
• EP80275 discloses that the 2, 2 '-azobis (2-methyl-prop ⁇ o nit ⁇ le) as well as the related compounds can be converted with excellent yield using the Pinner reaction with only the stoichiometric amount of alcohol, if the reaction is carried out in the presence of a compound containing an ether group. It is described that faster conversion (and not higher yield and / or selectivity) can be achieved by increasing the concentration of HCl in the reaction mixture. The presence of ether, however, poses problems, particularly in terms of separation and further processing.
• EP230586 has demonstrated that the preparation of azoiminoethers can be carried out in a single step in a single container according to a very easily controllable reaction during which the halo-oxidation of the hydrazonitnle and the immoetherification of the azonitrile take place .
• the preparation process according to EP230586 therefore comprises the reaction of a hydrazonitrile with chlorine in the presence of an alcohol capable of converting the cyano group into an immoether group in the presence of HCl
• the Applicant has surprisingly demonstrated a new process for preparing the azoiminoether salts and the corresponding azocarboxylic acid esters which achieves the above aims.
• the present invention therefore relates to a process for the preparation of azoiminoether salts by conversion of azonitrile according to the Pinner reaction in which the reaction is carried out in an aromatic solvent and in the presence of a large excess of HCl.
• the azonitrile is formed in si tu by reaction of the corresponding hydrazonitrile with chlorine.
• the solvent is selected from the group consisting of toluene, chlorobenzene, xylene, benzene; chlorobenzene being preferably used when azonitrile is formed in si tu.
• the alcohol is ethanol.
• the alcohol used consists of a mixture of alcohols, in particular a mixture comprising methanol, or methanol and ethanol.
• the azoiminoether hydrochloride corresponds to formula (II)
• RI, R2, R3 and R4, identical or different are independently selected from the group consisting of: linear or branched C1-C9 (preferably C1-C4) alkyl unsubstituted, or substituted by one or more substituents selected from the substituents hydroxyl, C1-C6 alkoxy, halogen; C3-C6 cycloalkyls, unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; C7-C12 aralkyls, unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; C7-C12 aryls unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; at least one of the combinations R1
• R and R ' are independently selected from the group consisting of linear or branched C1-C10, preferably C1-C4, aliphatic radicals.
• R and R ′ are different from each other and are selected from linear C1-C4 aliphatic radicals.
• RI, R2, R3 and R4 are C1-C4 alkyl groups.
• the invention also relates to a process for the preparation of an azocarboxylic acid ester comprising the synthesis of an azoiminoether hydrochloride by the process as defined above and the hydrolysis of the hydrochloride d azoiminoether thus obtained.
• the hydrolysis is carried out by successive addition of water to the reaction mixture or by pouring the reaction mixture into water, at a temperature between 15 ° C and 50 ° C, preferably d '' about 30 ° C
• the azoiminoether hydrochloride is filtered, washed with an organic solvent and then the hydrolysis is carried out by progressive addition filter cake in water at a temperature between 15 ° C and 50 ° C, preferably between 25 ° C and 35 ° C.
• the invention further relates to a process for the preparation of a liquid composition of azocarboxylic acid esters comprising the synthesis of the azoiminoether hydrochloride by the process as described above, the hydrolysis of the salts thus obtained in presence of water and isolation of the organic phase containing the esters.
• the heaviest alcohol is reacted first and then the least heavy alcohol in a second step.
• the invention also covers a liquid composition of azocarboxylic esters which can be obtained by the process described above and in particular a composition which is liquid at a temperature between -20 ° C and 20 ° C.
• the liquid composition comprises a first symmetrical ester of a first alcohol, a second symmetrical ester of a second alcohol, and a mixed ester of these first and second alcohols.
• said first symmetrical ester is the symmetrical methyl ester
• said second symmetrical ester is the symmetrical ethyl ester
• said mixed ester is the methyl-ethyl ester.
• the invention also relates to a process for the preparation of polymerization initiators comprising the synthesis of an ester of azocarboxylic acid by the process of preparation of esters of azocarboxylic acids as described above and, where appropriate, the transformation of this ester as an initiator by known methods.
• the subject of the present invention is the salts of mixed azoiminoethers corresponding to formula (II ')
• RI, R2, R3 and R4, identical or different are independently selected from the group consisting of: linear or branched C1-C9 alkyls (preferably C1-C4) unsubstituted, or substituted by one or more substituents selected from the substituents hydroxyl, C1-C6 alkoxy, halogen; C3-C6 cycloalkyls, unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; C7-C12 aralkyls, unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; C7-C12 aryls unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; at least one of the combinations R
• R and R ' are different from each other and are independently selected from the group consisting of linear or branched C1-C10, preferably C1-C4, aliphatic radicals. It preferably relates to the azoiminoether salts, in which R represents methyl and R ′ represents ethyl and in which RI, R2, R3 and R4 preferably represent C1-C4 alkyl groups.
• the present invention also relates to the esters of azocarboxylic acids obtained from the salts of mixed azoiminoethers as defined above.
• the present invention also relates to a process for the preparation of azoguanyl derivative comprising the synthesis of the corresponding azoiminoether hydrochloride by the process as described above and the reaction of the latter with ammonia or an acid in the presence of alcohol by any known process suitable for this purpose.
• the starting azonitrile used in the Pinner conversion reaction can be symmetrical or asymmetric.
• azonitrile mention may be made of the azonitriles corresponding to formula (I)
• RI, R2, R3 and R4, identical or different are independently selected from the group consisting of: linear or branched C1-C9 alkyls (preferably C1-C4) unsubstituted, or substituted by one or more substituents selected from hydroxyl, C1-C6 alkoxy, halogen; C3-C6 cycloalkyls, unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; C7-C12 aralkyls, unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; C7-C12 aryls unsubstituted or substituted by one or more substituents selected from C1-C6 alkyl, C1-C6 alkoxy, hydroxy, halogen; at least one of the combinations R1
• alcohol used in the Pinner conversion reaction linear or branched aliphatic alcohols, C1-C10, preferably linear and preferably C1-C4, are used. Ethanol and / or methanol are particularly preferred.
• the alcohol is used in an amount equal to the required stoichiometric amount or in a slight excess over the latter, ie up to 1.5 times the theoretical value.
• the term “alcohol” in the context of the present invention also means mixtures of alcohols as defined above, preferably mixtures containing at least methanol.
• mixtures of esters are obtained.
• a methanol / ethanol mixture is used as the reactant, a methyl ester, an ethyl ester and a mixed ethyl methyl ester are obtained.
• Alcohol mixtures also include mixtures of more than 2 alcohols, such as for example a methanol / ethanol / propanol mixture.
• Hydrochloric acid is used in large excess over the required stoichiometric amount.
• the Applicant has surprisingly highlighted on the one hand that the excess of HCl must be very large (up to, for example, 3 times the stoichiometry) and on the other hand that the amount of HCl to be added also depends on the nature of the alcohol used in the step of Pinner conversion.
• the molar ratio R HCl / azonitrile is> 2 when it is methanol and this ratio is> 3 when it is ethanol or a higher alcohol.
• the value of R is the weighted average of the R values present for each alcohol individually.
• R is between 2 and 6 for methanol and between 3 and 6, generally between 4 and 6 for higher alcohols.
• aromatic solvent it is possible to use any aromatic solvent, halogenated or non-halogenated, which is sufficiently volatile to be eliminated at the end of the reaction by evaporation at a relatively low temperature under reduced pressure.
• aromatic solvents include chlorobenzene, toluene, xylene, benzene.
• the Pinner conversion reaction is carried out at a temperature generally from 10 to 40 ° C, preferably from 15 to 25 ° C for a time which varies according to the nature of the azonitrile and the reaction temperature and which is around 8 to 24 hours.
• the conversion reaction according to the invention is generally carried out in the following manner: the solvent and the alcohol are mixed, and the azonitrile is added to the mixture thus obtained.
• the required quantity of anhydrous hydrochloric acid is then introduced into the reaction mixture in a known manner, while maintaining the temperature between 10 and 40 ° C, preferably between 15 and 25 ° C.
• the process can be carried out both without pressure.
• the azonitrile is prepared in situ from the corresponding hydrazonitrile by reaction with chlorine and an alcohol capable to convert the cyano group to an iminoether group in the presence of HCl, as described in EP230586.
• the reaction must be carried out in the presence of a large excess of HCl as defined above in relation to the Pinner conversion.
• the ratio R represents (HCl formed in if you + HCl added) / hydrazonitrile.
• the reaction of the invention can be carried out for dry hydrazonitrile, but the Applicant has demonstrated that it is possible to carry out it from wet hydrazonitrile.
• the water is removed by dissolving the wet hydrazonitrile in the reaction solvent and decanting the aqueous phase.
• the traces of water dissolved in the solvent can be removed by azeotropic entrainment before adding the alcohol and the other reagents.
• the Applicant has also demonstrated more than the reaction in si tu, when it is carried out in the presence of a halogenated solvent, particularly chlorinated, preferably chlorobenzene does not lead to toxic chlorinated derivatives during the preparation of the azoiminoether salts.
• a halogenated solvent particularly chlorinated, preferably chlorobenzene does not lead to toxic chlorinated derivatives during the preparation of the azoiminoether salts.
• RI, R2, R3 and R4 are as defined above and R and R ', identical or different, are independently selected from the group consisting of linear or branched C1-C10 aliphatic radicals, of preferably C1-C4; R and R 'preferably being different.
• azoiminoether salts in which R1, R2, R3 and R4 and R and R 'represent C1 to C4 alkyls are more particularly preferred.
• the azoiminoether hydrochloride thus obtained can be used for the preparation of compounds of the azoguanyl type by reaction with ammonia gas or a primary or secondary amine in the presence of alcohol by any known process suitable for this purpose.
• the azoiminoether hydrochloride thus obtained can also be used for the preparation of an azocarboxylic acid ester of formula (III)
• RI, R2, R3, R4, R and R ' are as defined above in relation to the salts of azoiminoethers.
• a subject of the invention is also the esters of azocarboxylic acids of formula (III ′)
• RI, R2, R3, R4, R and R ' are as defined above in relation to the salts of mixed azoiminoethers (i.e. R and R' are different from each other).
• azonitrile end of reaction which can be determined in known manner by infrared analysis of the CN band
• hydrolysis is carried out after isolation or not of the salt of azoiminoether by filtration.
• two clear phases are obtained. It is left to settle until complete separation of the phases.
• the aqueous phase is removed and the remaining organic phase comprising the azocarboxylic acid ester is concentrated under reduced pressure to remove the solvent.
• a variant of the isolation of the final product consists, after hydrolysis, in removing the reaction solvent by azeotropic entrainment with water under reduced pressure and then decanting the upper organic phase.
• the applicant has perfected the hydrolysis by progressive addition of water to the suspension of azoiminoether hydrochloride in the solvent. reaction or by casting this suspension in water while controlling the temperature, for example at a value between 15 and 50 ° C, preferably between 25 and 35 ° C.
• the present invention also relates to a process for the preparation of a liquid composition of esters (mixed and / or symmetrical) of azocarboxylic acids.
• This process comprises a first stage of synthesis of azoiminoether salts, either by reaction of azonitrile, or by in synthesis of azonitrile from 1 corresponding hydrazonitrile, in the presence of a mixture of alcohols like this is described above, then the hydrolysis of the salts obtained and the separation of the organic phase containing the esters by any suitable conventional technique.
• the liquid compositions thus obtained have the advantage of being liquid at temperatures close to ambient, and in certain cases down to -20 ° C., easy to handle, do not give off dust, are non-toxic and not cyanated .
• the present invention also relates to a process for the preparation of polymerization initiators comprising the synthesis of an azocarboxylic acid ester by the process as described above and, where appropriate, the transformation of this ester into an initiator by processes known.
• the invention also applies to the preparation of all the compounds which can be derived from esters of azocarboxylic acids, such as: alcohols and the corresponding acetates, alkanes, acids and corresponding amides.
• the more particularly preferred mixed azoiminoether salts are those derived from a mixture of alcohols selected from: methanol, ethanol, n-propanol and n-butanol, preferably from a mixture containing at least methanol.
• esters of azocarboxylic acids obtained from these mixed ethers also form part of the present invention.
• Example 3 In 600g of toluene is added 200g of 2, 2 '-hydrazobisisobutyronitrile wet (1 mole) while heating to approximately 35 ° C to obtain the dissolution of 1 hydrazobisisobutyromt ⁇ le. The lower aqueous phase is decanted, ie 31 g. The water dissolved in toluene is removed by azeotropic entrainment under vacuum. 110.4 g of ethanol (2.4 moles) and 0.2 g of sodium bromide, used as a chlorination catalyst, are added.
• A being the methyl ester of 2, 2 '-azobisiso- butyric acid
• the molar ratio is calculated by dividing the total number of groups -C00CH3 by the total number of groups -C00C2H5 present in the final mixture. For comparison of mixtures of products A
• a product prepared by mixing A and C in a molar ratio of 1.5 gives a solid / liquid mixture from approximately 15 ° C. and in a molar ratio 3.6 freezes at approximately 15 ° C.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Polymerization Catalysts (AREA)
• Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)

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• 1999
  • 1999-01-15 FR FR9900391A patent/FR2788517B1/fr not_active Expired - Lifetime
• 2000
  • 2000-01-07 DE DE60039582T patent/DE60039582D1/de not_active Expired - Fee Related
  • 2000-01-07 US US09/889,147 patent/US6407219B1/en not_active Expired - Lifetime
  • 2000-01-07 KR KR1020017008907A patent/KR100776703B1/ko not_active Expired - Fee Related
  • 2000-01-07 CN CNB008027595A patent/CN1211356C/zh not_active Expired - Lifetime
  • 2000-01-07 CA CA002359459A patent/CA2359459A1/en not_active Abandoned
  • 2000-01-07 EP EP00900534A patent/EP1147077B1/fr not_active Expired - Lifetime
  • 2000-01-07 JP JP2000593568A patent/JP2002534495A/ja active Pending
  • 2000-01-07 WO PCT/FR2000/000022 patent/WO2000042000A1/fr not_active Ceased
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• 2001
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