Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K15/00—Anti-oxidant compositions; Compositions inhibiting chemical change
  • C09K15/04—Anti-oxidant compositions; Compositions inhibiting chemical change containing organic compounds
  • C09K15/16—Anti-oxidant compositions; Compositions inhibiting chemical change containing organic compounds containing nitrogen
  • C09K15/18—Anti-oxidant compositions; Compositions inhibiting chemical change containing organic compounds containing nitrogen containing an amine or imine moiety
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B63/00—Purification; Separation; Stabilisation; Use of additives
  • C07B63/04—Use of additives
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/20—Use of additives, e.g. for stabilisation

Definitions

• the subject of the present invention is a composition which can be used as an inhibitor of the radical polymerization of ethylenically unsaturated monomers and a process intended to prevent the radical polymerization of such unsaturated monomers during their industrial preparation. It relates more particularly to vinyl aromatic monomers.
• Ethylene unsaturated monomers are prone to spontaneously polymerize under the action of heat.
• premature polymerization must be avoided during the manufacture, purification and storage of said monomers.
• early polymerization is detrimental since it causes a drop in production yields and fouling of the installations often making temporary cessation of production for maintenance reasons hence an additional cost of the production.
• Due to the exothermicity of the polymerization reaction explosions and fires are also to be feared.
• the distillation of certain ethylenically unsaturated monomers is particularly problematic when it requires the use of high temperatures: this is particularly the case for the distillation of vinyl aromatic derivatives such as styrene, methylstyrene and other vinylbenzenes.
• the object of the invention is to provide a composition intended to prevent premature polymerization of ethylenically unsaturated monomers during the production of said monomers.
• the subject of the present invention is therefore a composition intended to prevent the radical polymerization of ethylenically unsaturated monomers, characterized in that it comprises at least one benzenetriamine derivative corresponding to the general formula (I):
• a variant of the invention consists in associating the benzenetriamine derivative of the invention with one or more vehicles compatible with said monomer and with each of the constituents of the composition.
• Another variant of the invention is to combine it with another polymerization inhibitor.
• composition of the invention involves a compound corresponding to formula (I) in which the radical (s) R-i represent an electron donor group.
• electro-donor group is understood to mean a group as defined by H.C. BROWN in the work of Jerry MARCH - Advanced Organic Chemistry, chapter 9, pages 243 and 244 (1985).
• an alkyl radical linear or branched, having from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, .
• a linear or branched alkenyl radical having from 2 to 6 carbon atoms * , preferably from 2 to 4 carbon atoms, such as vinyl, allyl,.
• a linear or branched alkoxy or thioether radical having from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms such as the methoxy, ethoxy, propoxy, isopropoxy, butoxy radicals, an alkenyloxy radical, preferably an allyloxy radical or a phenoxy radical,.
• R 2 represents a valence bond or a divalent hydrocarbon radical, linear or branched, saturated or unsaturated, having from 1 to 6 carbon atoms such as, for example, methylene, ethylene, propylene, isopropylene, isopropylidene; the radicals R 3 , which are identical or different, represent a hydrogen atom or a linear or branched alkyl radical having from 1 to 6 carbon atoms,
• n is a number preferably less than or equal to 4, preferably equal to 1 or 2.
• the invention does not exclude that the three benzene rings carry radicals R-
• radicals R 4 which are identical or different, represent a hydroxyl group, or a linear or branched alkyl or alkoxy radical having from 1 to 4 carbon atoms.
• N, N ', N "-tri (p-methoxyphenyl) -1, 3,5-benzenetriamine and N, N', N" -tri (p-methylphenyl) -1, 3,5-benzenetriamine are preferably chosen.
• compositions of the invention comprising at least one benzenetriamine derivative of formula (la) constitute a particularly preferred embodiment of the invention.
• Certain benzenetriamine derivatives of formula (I) are commercial. The others are easily prepared by a person skilled in the art from commercial products.
• compositions of the invention are suitable for the stabilization of any monomer having at least one ethylenic unsaturation.
• the ethylenically unsaturated monomers more specifically include the aromatic ethylenically unsaturated monomers such as styrene, ⁇ -methylstyrene, divinylbenzene, vinyltoluene, vinylnaphthalene, styrenesulfonic acids, etc.
• Ethylene unsaturated monomers also include olefinic monomers comprising one or two unsaturations such as isoprene and butadiene; halogenated unsaturated monomers of the type of vinyl chloride, chloroprene, vinylidene chloride, vinylidene fluoride and vinyl fluoride; unsaturated acids such as acrylic acid, methacrylic acid and crotonic acid; unsaturated esters in particular the unsaturated esters of acrylic acid of the methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate; unsaturated esters of methacrylic acid such as methyl methacrylate, butyl methacrylate, lauryl methacrylate, dimethylaminoethyl methacrylate, stearyl methacrylate; vinyl acetate; unsaturated resins such as, for example, acrylated epoxy
• compositions of the invention are particularly effective in the case of the stabilization of aromatic ethylenically unsaturated monomers, in particular vinyl aromatic monomers such as styrene, ⁇ -methylstyrene, divinylbenzene, vinyltoluene, styrenesulfonic acids.
• vinyl aromatic monomers such as styrene, ⁇ -methylstyrene, divinylbenzene, vinyltoluene, styrenesulfonic acids.
• the invention preferably applies to styrene.
• compositions of the invention form either true solutions, that is to say that they consist of perfectly miscible ingredients, or emulsions, or else suspensions. According to a preferred embodiment, however, the compositions are in the form of true solutions.
• compositions of one or more vehicles are optional. It may prove to be necessary, however, when the solubility of the benzenetriamine derivatives of the composition in the monomer to be stabilized is low, or even insufficient. In this case, in fact, it is preferable to incorporate into the composition one or more vehicles compatible on the one hand with the monomer to be stabilized, and on the other hand with each of the other constituents of the composition.
• compatible is meant according to the invention a vehicle which is chemically inert with respect to the various ingredients of the composition and of the monomer. The nature of the vehicle therefore depends on the various constituents present as well as on the very nature of the monomer.
• the monomer is a vinyl aromatic derivative
• particularly suitable vehicles are benzene, toluene, xylene, ethylbenzene, styrene, acetophenone, methylphenylcarbinol or mixtures of these solvents.
• benzene toluene, xylene, ethylbenzene, styrene, acetophenone, methylphenylcarbinol or mixtures of these solvents.
• ethylbenzene it is preferred to use ethylbenzene.
• the benzenetriamine derivative with other conventionally used components such as polymerization retarders or other polymerization inhibitors.
• polymerization retarders or other polymerization inhibitors are easily determined by the skilled person. It depends on the nature of the polymer. Examples are given below, but they are in no way limiting.
• compositions of the invention advantageously contain one or more nitroaromatic derivatives.
• nitroaromatic derivatives Such compounds are known in the art as a polymerization retarder. It is also known to combine them with polymerization inhibitors. Note that the polymerization inhibitor prevents polymerization until a certain time beyond which the polymerization reaction starts normally. This time is the induction time. The longer the induction time, the more effective the inhibition. The role of the self-timer is different. It does not prevent polymerization but slows down the kinetics of polymerization. A more or less significant synergy is observed by association of an inhibitor and a retarder. Thus, the compositions of the invention containing at least one polymerization retarder and at least one polymerization inhibitor form a preferred subject of the invention.
• the nitroaromatic derivative is advantageously chosen from 1, 3-dinitrobenzene, 1, 4-dinitrobenzene, 2,6-dinitro-4-methylphenol, 2-nitro-4-methylphenol, 2,4-dinitro-1-naphthol, 2, 4,6-trinitrophenol (picric acid), 2,4-dinitro-6-methylphenol, 2,4-dinitrochlorobenzene, 2,4-dinitrophenol, 2,4-dinitro-6- sec-butylphenol, 4-cyano-2- nitrophenol, and 3-iodo-4-cyano-5-nitrophenol.
• the nitroaromatic derivatives are added to the composition so that the ratio of the total mass of the benzenetriamine type constituents of formula (I) to the total mass of the nitroaromatic type constituents is between 90/10 and 10/90, preferably between 80/20 and 20/80, better still between 60/40 and 40/60.
• This weight ratio is calculated by making the ratio of the total amount (by weight) of the benzenetriamine derivatives of formula (I) present in the composition to the total amount (by weight) of the nitroaromatic derivatives of the composition.
• the compositions of the invention may contain other polymerization inhibitors such as alkylated phenols such as tert-butyl-catechol, 2,5-di-tert-octylhydroquinone, 3,5 -di-tert- octylcatechol; nitroxide compounds such as 2,2,6,6-tetramethylpiperidine-N-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-oxo-2,2,6 , 6-tetramethylpiperidine-N-oxyl; 4-amino-2,2,6,6- 7 tetramethylpiperidine-N-oxyl; imidazolidines / imidazolines-N-oxyl as described in FR 97/04230, preferably 2,2,3,4,5,5-hexamethylimidazolidine-1-oxyl or any other inhibitor known in the art provided that these- these are compatible with the other ingredients of the composition under the operating conditions to which
• compositions of the invention are easily prepared by mixing the various constituents in the vehicle chosen.
• the subject of the invention is also a process for preventing the radical polymerization of an ethylenically unsaturated monomer, preferably a vinyl aromatic monomer.
• This method comprises, for example, adding to said monomer, an effective amount of a composition of the invention as defined above.
• the amount of benzenetriamine derivative to be added to achieve effective polymerization inhibition varies widely. It is a function of the monomer to be stabilized and of the operating conditions to which this monomer is subjected. It is clear that at high temperatures, the amount of inhibitor will be greater.
• the process of the invention is in fact applicable for the stabilization of the monomer, during manufacture and purification. However, it is not uncommon for the purification to be carried out by distillation of the monomer, the temperature at the reboiler being able to exceed 120 ° C.
• the ideal amount of inhibitor should be assessed on a case-by-case basis.
• a total quantity of benzenetriamine derivative of between 1 and 2000 ppm, preferably between 5 and 1000 ppm is generally sufficient, this quantity being expressed relative to the total weight of the monomer to be stabilized.
• nitroaromatic derivatives As indicated above, it is desirable to add to the ethylenically unsaturated aromatic monomer an effective amount of one or more nitroaromatic derivatives as a polymerization retarder.
• a polymerization retarder mention may again be made of 2,6-dinitro-4-methylphenol, 2,4-dinitro-6-methylphenol, and 2,4-dinitrophenol, but above all 2,4-dinitro-6-sec- butylphenol.
• the proportion of the nitroaromatic type retarder (s) is preferably such that the ratio of the total mass of benzenetriamine type constituents of formula (I) to the total mass of the nitroaromatic type constituents is between 90/10 and 10/90, better still between 80/20 and 20/80.
• This weight ratio is calculated by making the ratio of the total amount (by weight) of the benzenetriamine derivatives of formula (I) present in the composition to the total amount (by weight) of the nitroaromatic derivatives of the composition.
• the proportion of the polymerization inhibitor (s) is preferably such that the ratio of the total mass of constituents of the benzenetriamine derivative type of formula (I) to the total mass of the other inhibitors is between 90/10 and 10/90, better still between 80/20 and 20/80.
• the benzenetriamine derivative according to the invention optionally combined with a nitroaromatic derivative or other conventional polymerization inhibitors can be added to the monomer in a completely conventional manner.
• the point of introduction in the case of a distillation, is very variable: we can consider adding each of these compounds at the heat exchanger, pipes, pumps, reboilers, compressors or more usually containers. It should be understood that the addition can be carried out continuously or else repeated over time at one or different particular sites.
• the process of the invention is particularly advantageous in terms of the effectiveness of inhibiting radical polymerization of vinyl aromatic monomers.
• the resulting styrene (10 ml) is placed in a test tube and the appropriate amount of inhibitor is then added.
• Argon is introduced into the liquid phase of the reactor by bubbling (5 min) as well as into the sky of the reactor by bubbling (5 min).
• the tube set closed and placed in an oil bath thermostatically controlled at 100 ° C for 2 hours.
• the level of polymer formed after 2 hours is determined by the methanol precipitation method.
• a cooled sample of 10 ml of styrene is transferred to a glass flask containing approximately 50 ml of methanol, in order to precipitate the polystyrene formed which is insoluble in methanol.
• the precipitate is then filtered on a miiiipore filter and then the residue is dried in an oven at 40 ° C, before being weighed.
• the effectiveness of an inhibitor according to the invention is determined by measuring the induction time which represents the time to end of which the monomer begins to polymerize when it is heated in a temperature-controlled bath and in the presence of an initiator. This time is determined by a slight exothermicity of the sample studied.
• the measurements are carried out in a laboratory calorimeter, the time and temperature parameters are recorded and converted on a microcomputer.
• MMA methyl methacrylate
• AIBN azobisisobutyronitrile initiator
• Inhibitors Induction time Ti (min) phenothiazine (PTZ) 26 hydroquinone (HQ) 55
• the induction time values are better or equivalent to hydroquinone which is currently one of the best industrial inhibitors for the (meth) acrylates industry.
• Example 4 In this example, the association of N, N ', N "-tri (p-methoxyphenyl) - is described.

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• 1998
  • 1998-04-28 FR FR9805317A patent/FR2777884B1/fr not_active Expired - Fee Related
• 1999
  • 1999-04-26 JP JP2000545949A patent/JP2002513034A/ja not_active Withdrawn
  • 1999-04-26 WO PCT/FR1999/000982 patent/WO1999055797A1/fr not_active Application Discontinuation
  • 1999-04-26 EP EP99915835A patent/EP1080163A1/fr not_active Withdrawn
  • 1999-04-26 AU AU34275/99A patent/AU3427599A/en not_active Abandoned

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