WO2013026729A1 - Process for preparing an inhibitory composition comprising a compound based on at least two polymerization-inhibiting solids - Google Patents

Process for preparing an inhibitory composition comprising a compound based on at least two polymerization-inhibiting solids Download PDF

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Publication number
WO2013026729A1
WO2013026729A1 PCT/EP2012/065784 EP2012065784W WO2013026729A1 WO 2013026729 A1 WO2013026729 A1 WO 2013026729A1 EP 2012065784 W EP2012065784 W EP 2012065784W WO 2013026729 A1 WO2013026729 A1 WO 2013026729A1
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WIPO (PCT)
Prior art keywords
solids
temperature
polymerization
mixer
pmp
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PCT/EP2012/065784
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French (fr)
Inventor
Jacques Cavezzan
Jean-Claude Masson
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Rhodia Operations
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Application filed by Rhodia Operations filed Critical Rhodia Operations
Priority to KR1020147007646A priority Critical patent/KR20140065424A/en
Priority to CN201280052333.8A priority patent/CN103889939B/en
Priority to EP12747922.8A priority patent/EP2748133A1/en
Publication of WO2013026729A1 publication Critical patent/WO2013026729A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
    • C08F2/40—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation using retarding agents
    • 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 present invention relates to the field of the preparation of powder compositions, that is to say in powder form, having inhibitory properties on the polymerization of monomers. More specifically, it relates to a process for the preparation of a pulverulent composition essentially comprising a compound based on at least two solids each acting as a polymerization inhibitor.
  • the composition prepared according to the process of the invention is advantageously usable as an inhibitor of the radical polymerization of ethylenically unsaturated monomers.
  • the polymerization inhibitors are intended to prevent the polymerization of monomers, for example the radical polymerization of ethylenically unsaturated monomers, during their industrial preparation.
  • Ethylenically 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 a fouling of facilities often making it necessary to temporarily stop production for maintenance reasons, resulting in an additional cost of production.
  • Polymerization inhibitors are generally specific for the stabilization of particular families of monomers.
  • tert-butylcatechol is specific for preventing the radical polymerization of styrene and butadiene
  • hydroquinone is specific for preventing the radical polymerization of monomers comprising a (meth) acrylic unit, especially vinyl chloride, ethyl acetate or vinyl, of acrolein, methacrolein, acrylic acid, methacrylic acid and esters of said acids such as methyl methacrylate.
  • the present invention proposes to provide a new process for the preparation of a pulverulent composition at ambient temperature exhibiting inhibitory properties on the polymerization of monomers.
  • One of the objectives sought by the present invention is the provision of a method based on a simple procedure to be implemented on an industrial scale, with the special aim of avoiding a very delicate control of the temperature for the production of a product.
  • powdery composition and having inhibiting properties on the polymerization of monomers The present invention relates to a process for the preparation of a pulverulent composition having inhibiting properties on the polymerization of monomers and having a melting temperature Tf comprising:
  • Said step i) of the preparation process according to the invention implements at least two elementary solids powder, that is to say in the form of powder.
  • Said solids are monomer polymerization inhibitors. They are chosen so that the composition prepared according to the process of the invention is in pulverulent form at room temperature.
  • the ambient temperature is defined by a temperature range generally ranging from 10 to 30 ° C, preferably from 15 to 30 ° C and more preferably from 15 to 25 ° C.
  • said pulverulent elementary solids used as polymerization inhibitor advantageously have a melting point greater than or equal to 40 ° C, very advantageously greater than or equal to 50 ° C and even more advantageously greater than or equal to 100 ° C.
  • Said elemental solids used as a polymerization inhibitor generally have a melting point of less than 220 ° C.
  • said solids each having inhibiting properties on the polymerization of monomers consist of a molecule having at least one benzene ring and advantageously at least one heteroatom chosen from nitrogen, oxygen and sulfur. More preferably, said solids consist of a molecule having at least one benzene ring carrying at least one hydroxyl radical -OH.
  • said solids are involved in mechanisms for inhibiting the polymerization of monomers, for example in the radical polymerization inhibition mechanisms of ethylenically unsaturated monomers. According to the invention, said solids are devoid of organoleptic properties.
  • At least one of said powdery elemental solids is crystallized and even more preferably, said two powdery elemental solids are crystallized.
  • said solids are selected from hydroquinone (para-dihydroxy-1,4-benzene, denoted HQ in the following description), catechol or pyrocatechol (ortho-dihydroxy-1,2-benzene, noted PC in the following description), resorcinol or resorcinol (meta-dihydroxy-1,3-benzene, noted R in the following description), pyrogallol (1,2,3-trihydroxybenzene, noted PYRO in the following of the description), para-methoxyphenol (or methylhydroquinone, noted PMP in the following description), 4-tert-butylcatechol (or 4-tert-butylpyrocatechol, noted TBC in the following description) and phenothiazine (PTZ noted in the following the description).
  • hydroquinone para-dihydroxy-1,4-benzene, denoted HQ in the following description
  • catechol or pyrocatechol ortho-dihydroxy-1,2-benzene, noted PC
  • said elementary solids used as a polymerization inhibitor are preferably chosen from the following binary combinations: HQ-PC, HQ-R, HQ-PYRO, HQ- PMP, HQ-TBC, PC-R, PC-PYRO, PC-PMP, PC-TBC, R-PYRO, R-PMP, R-TBC, PMP-PYRO, PMP-TBC, TBC-PYRO, and PMP-PTZ . More advantageously, said solids are chosen from the binary combinations: HQ-PC, HQ-R, HQ-PYRO, PC-TBC, and PC-PMP.
  • said process is carried out in the presence of at least three pulverulent elementary solids each having a role of polymerization inhibitor.
  • each of said three solids are selected from hydroquinone, catechol, resorcinol, pyrogallol, para-methoxyphenol, 4-tert-butylcatechol and phenothiazine.
  • said elementary solids used as a polymerization inhibitor are preferably chosen from the following ternary combinations: HQ-PC-R, HQ-PC-PYRO, HQ-PC-PMP, HQ-PC-TBC, HQ R-PYRO, HQ-R-PMP, HQ-R-TBC, HQ-PYRO-PMP, HQ-PYRO-TBC, HQ-PMP-TBC, PC-R-PYRO, PC-R-PMP, PC-R -TBC, R-PYRO-PMP, R-PYRO-TBC, R-PMP-TBC, HQ-PMP-PTZ and PYRO-PMP-TBC.
  • said elementary solids are introduced into the mixer at any molar ratio suitable for the preparation of said pulverulent inhibitor composition obtained according to the method of the invention.
  • hydroquinone and catechol are introduced into said mixer in the following proportions: from 15 to 25%, preferably 18 to 22%, more preferably 20 to 22%, by weight of hydroquinone and 75 to 85%, preferably 78 to 82%, more preferably 78 to 80%, by weight of catechol.
  • hydroquinone and resorcinol are introduced into said mixer in the following proportions: from 17 to 27%, preferably from 20 to 25%, more preferably from 21 to 23%, by weight of hydroquinone and from 73 to 83%, preferably from 75 to 80%, more preferably preferred from 77 to 79%, by weight of resorcinol.
  • hydroquinone and pyrogallol are introduced into said mixer in the following proportions: from 20 to 30%, preferably from 22 to 27%, more preferably from 23 to 26%, by weight of hydroquinone and from 70 to 80%, preferably from 73 to 78%, more preferably from 74 to 77%, by weight. of pyrogallol.
  • the catechol and para-methoxyphenol are introduced into said mixer in the following proportions: from 23 to 33 %, preferably 25 to 30%, more preferably 27 to 29%, by weight of catechol and 67 to 77%, preferably 70 to 75%, more preferably 71 to 73%, weight of para-methoxyphenol.
  • said powdery elementary solids are introduced separately, that is to say each in the pure state, into said mixer.
  • Said solids can be introduced simultaneously or one after the other in any order.
  • Each of said solids can be introduced gradually or not.
  • the enclosure of said mixer Prior to the introduction of said solids, the enclosure of said mixer is heated to a temperature T less than the melting temperature of the elemental solid having the lowest melting temperature, said solid being chosen from said elemental solids used in the process according to the invention.
  • Said temperature T is below the melting start temperature of the composition prepared according to the method of the invention.
  • the enclosure of said mixer is heated to a temperature T advantageously between 78 and 85 ° C. very advantageously between 80 and 85 ° C.
  • HQ-R hydroquinone and resorcinol
  • a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and pyrogallol (HQ-PYRO)
  • the enclosure of said mixer is heated to a temperature T advantageously between 100 and 108 ° C, very advantageously between 102 and 107 ° C.
  • HQ-PYRO hydroquinone and pyrogallol
  • the enclosure of said mixer is heated to a temperature T advantageously between 26 and 33 ° C, very advantageously between 28 and 32 ° C.
  • Said steps i) and ii) of the process according to the invention are carried out in a mixer. It is advantageously a mixer with plowshares, a vane mixer or a ribbon mixer (s), these mixers being well known to those skilled in the field of powder mixing. .
  • Said mixer is advantageously provided with a double jacket to ensure the various heat transfers by circulating a coolant, preferably water or a silicone oil, in the jacket.
  • the heat transfer fluid is maintained at a temperature greater than or equal to the temperature T inside the enclosure of said mixer.
  • the coolant is maintained at a temperature greater than 1 to 5 ° C at said temperature T.
  • Said two elementary solids polymerization inhibitors in pulverulent form are introduced separately into said mixer and then mixed therein according to said step ii) of the process according to the invention.
  • Said solids are for example in the form of crystals, granules or flakes. In particular, it is possible to mix a solid in the form of flakes and a solid in the form of crystals or else to mix two solids in the form of flakes.
  • At least one of said elementary solids polymerization inhibitors is preheated to a temperature Ti before being introduced into said mixer, said temperature Ti being close to said temperature T at which mixing is carried out according to said step ii).
  • said elementary polymerization inhibiting solids are introduced at a temperature Ti; said solids may be preheated and introduced into said mixer at the same temperature Ti or at a slightly different temperature Ti. More precisely, said temperature Ti is advantageously chosen such that T - 20 ° C ⁇ Ti ⁇ T + 20 ° C.
  • the mixture of said polymerization inhibiting elemental solids, in pulverulent form is produced under isothermal conditions, that is to say at a constant temperature, equal to the temperature T at which the enclosure of the mixer was heated, as soon as said solids were introduced into said mixer.
  • Preheating at least one of said two polymerization inhibiting elemental solids to a temperature T 1 as defined above, preferably both of said elementary polymerization inhibiting solids allows isothermal temperature mixing in said mixer.
  • the mixture is naturally operated in the solid phase.
  • Said mixer is advantageously subjected to agitation.
  • the stirring conditions are chosen so that there are no significant shears. Thus, a slow stirring speed is preferred.
  • the mixer is advantageously placed under an inert atmosphere throughout the duration of implementation of the method according to the invention.
  • steps i) and ii) of the process according to the invention are advantageously carried out under an inert atmosphere, preferably under nitrogen. More preferably, said steps i) and ii) are carried out under a wet nitrogen or dry nitrogen atmosphere.
  • the humidification of the nitrogen stream is advantageously ensured by bubbling nitrogen into the water.
  • the flow of inert gas, preferably nitrogen is advantageously heated to a temperature equal to T ⁇ 10 ° C, the temperature T being that at which the chamber of the mixer is heated.
  • the amount of water present in the nitrogen represents, for example, from 1 to 5% by weight of the weight of the nitrogen, preferably from 2 to 3% by weight of the weight of the nitrogen.
  • Dry nitrogen means a stream of nitrogen comprising less than 0.5 g, preferably less than 0.3 g of water per kg of nitrogen.
  • a preferred embodiment of implementing said step ii) of the method according to the invention consists in producing said mixture of said solids in a humid atmosphere.
  • the humidity is for example ensured by a flow of dry steam, a flow of wet nitrogen.
  • step ii) of the process according to the invention leads to the transformation of said solids into said composition with inhibiting properties. which is recovered according to said step Ni) of the method according to the invention.
  • Said step ii) is carried out for a sufficient time in order to obtain the transformation, preferably the complete transformation, of solids into said composition. This duration is variable and is in particular a function of the elementary solids used and the agitation.
  • Said composition is recovered before or after cooling. Operated inside or outside said mixer, the cooling of said composition obtained is carried out at a temperature below 40 ° C, preferably below 35 ° C.
  • the lower limit of the cooling temperature is advantageously ambient temperature.
  • Said composition is advantageously allowed to cool inside or outside said mixer.
  • a cooling system outside the mixer is used in which the composition prepared according to the method of the invention is introduced.
  • composition prepared according to the process of the invention results from the conversion of the elementary polymerization inhibiting solids used in said process into a defined compound.
  • the composition prepared according to the process of the invention is a composition exhibiting inhibiting properties on the polymerization of monomers, preferably on the radical polymerization of ethylenically unsaturated monomers.
  • composition prepared according to the process of the invention is a powdery composition, that is to say that it is in powder form.
  • the composition is in the form of flakes, crystals, granules.
  • composition prepared according to the process of the invention is further characterized by its melting temperature denoted Tf, which is different from each of the melting temperatures of each of said elementary solids used in the process according to the invention and lower than the most low melting temperatures of the solids used in the process according to the invention.
  • said composition has a melting temperature Tf greater than or equal to 30 ° C, preferably greater than or equal to 40 ° C.
  • a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and catechol (HQ-PC) has a melting temperature equal to 90 ⁇ 2 ° C.
  • a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and pyrogallol (HQ-PYRO) has a melting temperature of 11 ⁇ 2 ° C.
  • a pulverulent composition with inhibiting properties comprising a compound based on catechol and para-methoxyphenol (PC-PMP) has a melting point of 36 ⁇ 2 ° C.
  • said composition prepared according to the process of the invention is a crystallized composition. It is advantageously characterized by an X-ray diffraction spectrum of its own having lines for angles 2 ⁇ different from those presented by the lines appearing on each of the X-ray diffraction spectra of the elementary solids from which said composition prepared according to the process of the invention.
  • the composition prepared according to the process of the invention has a bulk density (not packed) higher than that presented by each of the elementary solids used in the process according to the invention.
  • the bulk density (unpacked) is conventionally measured in a compaction volumenometer, for example in a Delta Labo type STAV apparatus.
  • the solid phase transformation implemented according to the process of the invention preferentially leads to a densification of the mixture operated according to said step ii) of the process according to the invention.
  • the composition obtained according to the method of the invention comprises at least 80% by weight, preferably at least 90% by weight of a defined compound derived from at least two elementary solids polymerization inhibitors. More preferably, said composition obtained according to the process of the invention consists entirely of such a compound.
  • the process according to the invention is an advantageous and simple process to implement.
  • the mixing of the polymerization inhibitor elementary solids, in powder form, under isothermal conditions, ie at a constant temperature, in accordance with said step ii) of the process according to the invention makes it possible to have 'a simplified process in wherein the preheating of at least one of said elementary solids, preferably said elemental solids, avoids the setting up of temperature sensitive programming.
  • the elementary solids are introduced at the desired temperature as soon as they are mixed.
  • the process according to the invention leads to the preparation of a composition generally having directly the desired particle size.
  • composition prepared according to the process of the invention is advantageously used as an inhibiting composition for the immediate termination of polymerizations of monomers, preferably radical polymerizations of monomers having at least one ethylenic unsaturation.
  • it is very advantageously used for the stabilization of said monomers during manufacture and purification. It is still very advantageously used to instantly terminate the undesired polymerization of monomers during transport and / or storage of mixture containing said monomers.
  • composition prepared according to the process of the invention for immediately stopping the polymerization of one or more monomer (s), preferably the radical polymerization of one or more monomers (s) having at least one ethylenic unsaturation is implemented by the addition to said said monomer (s) of an effective amount of a composition obtained according to the method of the invention.
  • the amount of said composition to be added to achieve effective inhibition of polymerization varies to a large extent. It is a function of the monomer (s) to be stabilized and the operating conditions to which the said monomer (s) are (are) subjected. It goes without saying that at high temperatures, the amount of said inhibiting composition will be greater. Thus the quantity of said composition will be evaluated on a case by case basis.
  • the monomers exhibiting at least one ethylenic unsaturation are advantageously chosen from aromatic monomers with ethylenic unsaturation and aliphatic monomers with ethylenic unsaturation.
  • aromatic ethylenically unsaturated monomers styrene, ⁇ -methylstyrene, vinyltoluene, divinylbenzene, vinylnaphthalene and styrenesulfonic acids are preferred.
  • ethylenically unsaturated aliphatic monomers olefinic monomers comprising one or two unsaturations, halogenated unsaturated monomers, unsaturated acids, unsaturated esters, unsaturated resins, unsaturated amides, unsaturated nitriles, unsaturated ethers are preferred.
  • said ethylenically unsaturated aliphatic monomers are preferably chosen from isoprene, butadiene, vinyl chloride, chloroprene, vinylidene chloride, vinylidene fluoride, vinyl fluoride, acrylic acid, and the like.
  • methacrylic acid crotonic acid
  • unsaturated esters of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylate, 2-hydroxyethyl, hydroxypropyl acrylate
  • unsaturated esters of methacrylic acid such as methyl methacrylate, butyl methacrylate, lauryl methacrylate, dimethylaminoethyl methacrylate, stearyl methacrylate, vinyl, acrylated epoxy resins and polyethylene glycol diacrylate, acrylamide, ⁇ , ⁇ -dimethylacrylamide, methylenebisacrylamide and N-vinylpyrrolidone, acrylonitrile, methyl vinyl ether, vinylpyridines, diethyl vinylphosphonate.
  • the inhibitory properties of the composition obtained according to the method of the invention on the polymerization of the monomers are evaluated with regard to a test which determines the induction time.
  • the composition prevents polymerization for a period of time beyond which the polymerization reaction normally starts. This time is called induction time. The longer it is, the more effective the inhibition.
  • MMA methyl methacrylate
  • the effectiveness of the composition prepared according to the process of the invention for methyl methacrylate is determined by measuring the induction time which represents the time at which the monomer begins to polymerize when heated in a hot water bath. regulated temperature and presence of an initiator. This induction time corresponds to the time at the end of which appears a visible exotherm which indicates the beginning of polymerization.
  • the protocol for determining the induction time is as follows:
  • a solution is prepared based on pure methyl methacrylate (MMA) containing 2000 ppm of an inhibiting solid.
  • MMA methyl methacrylate
  • a solution B is prepared based on pure methyl methacrylate (MMA) containing 200 ppm of an initiator.
  • the temperature in the tube is raised continuously until it begins to increase (increase of the order of 0.3 ° C).
  • the induction time corresponds to the visible exotherm which indicates the beginning of the MMA polymerization.
  • the temperature variation curve ⁇ as a function of time is recorded continuously. The greater the induction time, the more effective the inhibitory composition tested is at constant weight concentration. The induction time thus determined is compared with that obtained by testing a mixture which contains an initiator but which does not contain an inhibiting composition.
  • the melting point or melting temperature of the composition prepared according to the method of the invention is measured by differential scanning calorimetry.
  • the measurement is carried out using a Mettler differential analyzer DSC822e under the following conditions:
  • the temperature programming is started and the fusion profile is obtained on a thermogram.
  • the melting temperature is defined from a thermogram produced under the preceding operating conditions.
  • the onset temperature is selected: temperature corresponding to the maximum slope of the melting peak. 2. X-ray diffraction spectrum.
  • the X-ray diffraction spectrum of the composition prepared according to the process of the invention is determined using the X'Pert Pro MPD PANalytical device equipped with an X 'Celerator detector, under the following conditions:
  • Example 1 An example is given below illustrating the present invention without limitation.
  • Example 1 An example is given below illustrating the present invention without limitation.
  • PC-PMP catechol and para-methoxyphenol
  • the inlet / outlet coolant temperatures, as well as the internal temperature of the mixer are measured by Pt probe (100 ⁇ at 0 ° C) regulated and recorded throughout the process.
  • the mixer is preheated for one hour at a temperature of 32 ° C +/- 1 ° C, maintaining the jacket at a temperature of 34 ° C +/- 1 ° C to compensate for heat losses.
  • the mixer is swept by a nitrogen flow dry of 240 liters per hour.
  • the granulator operates at atmospheric pressure. Lift granulator is equipped with a bag filter.
  • the catechol and para-methoxyphenol crystals are preheated independently in an oven to obtain a homogeneous temperature for each of the solids: 2,271 kg of para-methoxyphenol (PMP) are preheated to a temperature of 35 ° C +/- 1 ° C in an oven and 0.883 kg of catechol (PC) are preheated to a temperature of 46.3 ° C +/- 1 ° C in another oven.
  • PMP para-methoxyphenol
  • PC catechol
  • the pre-heated para-methoxyphenol (PMP) is introduced into the mixer and then introduced the preheated catechol.
  • the mixture is endothermic (of the order of 2 kcal / kg of mixture).
  • the agitation of the mixer is put into operation at a speed of 100 rpm for 5 minutes.
  • stirring is reduced at a speed of 40 rpm and is maintained for 45 minutes.
  • the temperature in the mixer is around 32 ° C throughout the stirring period during the transformation.
  • a cooling step is then carried out by bringing the coolant to 15 ° C in the jacket.
  • the cooling time is of the order of 30 minutes and the compound is thus cooled to a temperature of 22 ° C +/- 1 ° C.
  • the agitation in the mixer and the nitrogen circulation are stopped.
  • the mixer is then emptied and the defined compound resulting from the mixture of PC and PMP is recovered.
  • the compound obtained is a powdery compound. It has a bulk density (unpacked) of 0.82 +/- 0.01 and a melting point of 36.7 ° C +/- 1 ° C.

Abstract

Described herein is a process for preparing a pulverulent composition which has inhibitory properties on monomer polymerization and which has a melting temperature Mp, said process comprising: i) the introduction into a mixer, the chamber of which has been preheated to a temperature T below Mp, of at least two polymerization-inhibiting elementary solids, said solids being introduced separately into said mixer in pulverulent form, ii) the mixing in said mixer, in the absence of any external liquid phase, of said solids at a temperature T below the temperature Mp, at least one of said polymerization-inhibiting elementary solids being introduced into said mixer at a temperature Ti such that the mixing is carried out under isothermal conditions at a temperature fixed at said temperature T, and iii) the recovery of said pulverulent composition.

Description

PROCEDE DE PREPARATION D'UNE COMPOSITION INHIBITRICE COMPRENANT UN COMPOSE A BASE D'AU MOINS DEUX SOLIDES  PROCESS FOR PREPARING AN INHIBITORY COMPOSITION COMPRISING A COMPOUND BASED ON AT LEAST TWO SOLIDS
INHIBITEURS DE POLYMERISATION  POLYMERIZATION INHIBITORS
La présente invention se rapporte au domaine de la préparation de compositions pulvérulentes, c'est-à-dire sous forme de poudre, présentant des propriétés inhibitrices sur la polymérisation de monomères. Plus précisément, elle se rapporte à un procédé de préparation d'une composition pulvérulente comprenant essentiellement un composé à base d'au moins deux solides jouant chacun le rôle d'inhibiteur de polymérisation. La composition préparée selon le procédé de l'invention est avantageusement utilisable comme inhibiteur de la polymérisation radicalaire de monomères à insaturation éthylénique. The present invention relates to the field of the preparation of powder compositions, that is to say in powder form, having inhibitory properties on the polymerization of monomers. More specifically, it relates to a process for the preparation of a pulverulent composition essentially comprising a compound based on at least two solids each acting as a polymerization inhibitor. The composition prepared according to the process of the invention is advantageously usable as an inhibitor of the radical polymerization of ethylenically unsaturated monomers.
Les inhibiteurs de polymérisation sont destinés à empêcher la polymérisation de monomères, par exemple la polymérisation radicalaire de monomères à insaturation éthylénique, pendant leur préparation industrielle. The polymerization inhibitors are intended to prevent the polymerization of monomers, for example the radical polymerization of ethylenically unsaturated monomers, during their industrial preparation.
Les monomères à insaturation éthylénique sont enclin à polymériser spontanément sous l'action de la chaleur. Or, une polymérisation prématurée doit être évitée lors de la fabrication, de la purification et du stockage desdits monomères. En cours de fabrication ou de purification, une polymérisation précoce est préjudiciable puisqu'elle provoque une chute des rendements de production et un encrassement des installations rendant souvent nécessaire l'arrêt momentané de la production pour des raisons de maintenance d'où un surcoût de la production. Ethylenically unsaturated monomers are prone to spontaneously polymerize under the action of heat. However, premature polymerization must be avoided during the manufacture, purification and storage of said monomers. During manufacture or purification, early polymerization is detrimental since it causes a drop in production yields and a fouling of facilities often making it necessary to temporarily stop production for maintenance reasons, resulting in an additional cost of production.
De façon à empêcher la polymérisation des monomères à insaturation éthylénique, il est connu d'ajouter un ou plusieurs inhibiteurs soit de façon préventive en cours de fabrication soit encore directement auxdits monomères avant leur utilisation (US 6.518.374). Il est également connu des composés eutectiques issus de deux inhibiteurs de polymérisation (Ming-Jer Lee et al, J. Chem. Eng. Data 1997, 42, 349-352, M. S. Dhillon, Z. phys. Chemie, Leipzig 259, (1978), 2, 243-248).  In order to prevent the polymerization of ethylenically unsaturated monomers, it is known to add one or more inhibitors either pre-emptively during manufacture or directly to said monomers prior to their use (US 6,518,374). Eutectic compounds from two polymerization inhibitors are also known (Ming-Jer Lee et al., J. Chem Eng., Data 1997, 42, 349-352, MS Dhillon, Z. Phys Chemie, Leipzig 259, (1978). ), 2, 243-248).
Les inhibiteurs de polymérisation sont généralement spécifiques à la stabilisation de familles particulières de monomères. Par exemple, le tertiobutylcatéchol est spécifique pour empêcher la polymérisation radicalaire du styrène et du butadiène alors que l'hydroquinone est spécifique pour empêcher la polymérisation radicalaire de monomères comportant un motif (méth)acrylique, notamment du chlorure de vinyle, de l'acétate de vinyle, de l'acroléine, de la méthacroléine, de l'acide acrylique, de l'acide méthacrylique et des esters desdits acides tel que le méthacrylate de méthyle. Polymerization inhibitors are generally specific for the stabilization of particular families of monomers. For example, tert-butylcatechol is specific for preventing the radical polymerization of styrene and butadiene, whereas hydroquinone is specific for preventing the radical polymerization of monomers comprising a (meth) acrylic unit, especially vinyl chloride, ethyl acetate or vinyl, of acrolein, methacrolein, acrylic acid, methacrylic acid and esters of said acids such as methyl methacrylate.
Aussi, en vue d'exploiter la spécificité des inhibiteurs connus et d'éviter de recourir à autant d'inhibiteurs que de familles de monomères, le besoin de disposer de compositions inhibitrices à base de composés issus de plusieurs inhibiteurs est grand de manière à pouvoir utiliser lesdites compositions dans des applications plus larges. Par ailleurs, il est recherché la mise à disposition de compositions inhibitrices présentant des propriétés stabilisatrices, physiques et de mise en œuvre (granulométrie) améliorées. Therefore, in order to exploit the specificity of the known inhibitors and to avoid using as many inhibitors as families of monomers, the need to have inhibitory compositions based on compounds derived from several inhibitors is large so as to be able to use said compositions in broader applications. Furthermore, it is sought the provision of inhibiting compositions having improved stabilizing, physical and processing properties (granulometry).
La présente invention se propose de fournir un nouveau procédé de préparation d'une composition pulvérulente à température ambiante présentant des propriétés inhibitrices sur la polymérisation de monomères. Un des objectifs recherchés par la présente invention est la mise à disposition d'un procédé reposant sur un mode opératoire simple à mettre en oeuvre à l'échelle industrielle en visant spécialement à éviter un contrôle très délicat de la température pour la fabrication d'une composition pulvérulente et présentant des propriétés inhibitrices sur la polymérisation de monomères. La présente invention a pour objet un procédé de préparation d'une composition pulvérulente présentant des propriétés inhibitrices sur la polymérisation de monomères et ayant une température de fusion Tf comprenant : The present invention proposes to provide a new process for the preparation of a pulverulent composition at ambient temperature exhibiting inhibitory properties on the polymerization of monomers. One of the objectives sought by the present invention is the provision of a method based on a simple procedure to be implemented on an industrial scale, with the special aim of avoiding a very delicate control of the temperature for the production of a product. powdery composition and having inhibiting properties on the polymerization of monomers. The present invention relates to a process for the preparation of a pulverulent composition having inhibiting properties on the polymerization of monomers and having a melting temperature Tf comprising:
i) l'introduction dans un mélangeur dont l'enceinte a été préalablement chauffée à une température T inférieure à Tf d'au moins deux solides élémentaires inhibiteurs de polymérisation, lesdits solides étant introduits séparément dans ledit mélangeur sous forme pulvérulente,  i) introducing into a mixer whose chamber has been heated beforehand to a temperature T less than Tf of at least two elementary polymerization inhibiting solids, said solids being introduced separately into said mixer in pulverulent form,
ii) le mélange dans ledit mélangeur, en l'absence de toute phase liquide extérieure, desdits solides à une température T inférieure à la température Tf, au moins l'un desdits solides élémentaires inhibiteurs de polymérisation étant introduit dans ledit mélangeur à une température Ti telle que le mélange se réalise en conditions isothermes à une température fixée à ladite température T, et  ii) mixing in said mixer, in the absence of any external liquid phase, said solids at a temperature T below the temperature Tf, at least one of said elementary polymerization-inhibiting solids being introduced into said mixer at a temperature Ti such that the mixing is carried out under isothermal conditions at a temperature set at said temperature T, and
iii) la récupération de ladite composition pulvérulente.  iii) recovering said powdery composition.
Ladite étape i) du procédé de préparation selon l'invention met en œuvre au moins deux solides élémentaires pulvérulents, c'est-à-dire sous forme de poudre. Lesdits solides sont des inhibiteurs de polymérisation de monomères. Ils sont choisis de sorte que la composition préparée selon le procédé de l'invention se trouve sous forme pulvérulente à température ambiante. Selon l'invention, la température ambiante est définie par une plage de température allant généralement de 10 à 30°C, préférentiellement de 15 à 30°C et plus préférentiellement de 15 à 25°C. Plus particulièrement, lesdits solides élémentaires pulvérulents utilisés comme inhibiteur de polymérisation présentent avantageusement une température de fusion supérieure ou égale à 40°C, très avantageusement supérieure ou égale à 50°C et de manière encore plus avantageuse supérieure ou égale à 100°C. Lesdits solides élémentaires utilisés comme inhibiteur de polymérisation présentent généralement un température de fusion inférieure à 220°C. Said step i) of the preparation process according to the invention implements at least two elementary solids powder, that is to say in the form of powder. Said solids are monomer polymerization inhibitors. They are chosen so that the composition prepared according to the process of the invention is in pulverulent form at room temperature. According to the invention, the ambient temperature is defined by a temperature range generally ranging from 10 to 30 ° C, preferably from 15 to 30 ° C and more preferably from 15 to 25 ° C. More particularly, said pulverulent elementary solids used as polymerization inhibitor advantageously have a melting point greater than or equal to 40 ° C, very advantageously greater than or equal to 50 ° C and even more advantageously greater than or equal to 100 ° C. Said elemental solids used as a polymerization inhibitor generally have a melting point of less than 220 ° C.
De manière préférée, lesdits solides présentant chacun des propriétés inhibitrices sur la polymérisation de monomères sont constitués d'une molécule présentant au moins un noyau benzénique et avantageusement au moins un hétéroatome choisi parmi l'azote, l'oxygène et le soufre. De manière plus préférée, lesdits solides sont constitués d'une molécule présentant au moins un noyau benzénique portant au moins un radical hydroxyle -OH. Ces solides interviennent dans les mécanismes d'inhibition de polymérisation de monomères, par exemple dans les mécanismes d'inhibition de polymérisation radicalaire de monomères à insaturation éthylénique. Selon l'invention, lesdits solides sont dépourvus de propriétés organoleptiques. Preferably, said solids each having inhibiting properties on the polymerization of monomers consist of a molecule having at least one benzene ring and advantageously at least one heteroatom chosen from nitrogen, oxygen and sulfur. More preferably, said solids consist of a molecule having at least one benzene ring carrying at least one hydroxyl radical -OH. These solids are involved in mechanisms for inhibiting the polymerization of monomers, for example in the radical polymerization inhibition mechanisms of ethylenically unsaturated monomers. According to the invention, said solids are devoid of organoleptic properties.
De manière préférée, au moins l'un desdits solides élémentaires pulvérulents est cristallisé et de manière encore plus préférée, lesdits deux solides élémentaires pulvérulents sont cristallisés. Preferably, at least one of said powdery elemental solids is crystallized and even more preferably, said two powdery elemental solids are crystallized.
De manière plus préférée, lesdits solides sont choisis parmi l'hydroquinone (para-dihydroxy-1 ,4-benzène, noté HQ dans la suite de la description), le catéchol ou pyrocatéchine (ortho-dihydroxy-1 ,2-benzène, noté PC dans la suite de la description), le résorcinol ou résorcine (méta-dihydroxy-1 ,3- benzène, noté R dans la suite de la description), le pyrogallol (1 ,2,3- trihydroxybenzène, noté PYRO dans la suite de la description), le para- méthoxyphénol (ou méthylhydroquinone, noté PMP dans la suite de la description), le 4-tertiobutylcatéchol (ou 4-tertiobutylpyrocatéchol, noté TBC dans la suite de la description) et la phénothiazine (notée PTZ dans la suite de la description). Selon un premier mode particulier de mise en œuvre du procédé selon l'invention, lesdits solides élémentaires utilisés en tant qu'inhibiteur de polymérisation sont préférentiellement choisis parmi les combinaisons binaires suivantes : HQ-PC, HQ-R, HQ-PYRO, HQ-PMP, HQ-TBC, PC-R, PC-PYRO, PC-PMP, PC-TBC, R-PYRO, R-PMP, R-TBC, PMP-PYRO, PMP-TBC, TBC- PYRO, et PMP-PTZ. De manière plus avantageuse, lesdits solides sont choisis parmi les combinaisons binaires : HQ-PC, HQ-R, HQ-PYRO, PC-TBC, et PC- PMP. Selon un second mode particulier de mise en œuvre du procédé selon l'invention, ledit procédé est mis en œuvre en présence d'au moins trois solides élémentaires pulvérulents présentant chacun un rôle d'inhibiteur de polymérisation. De manière préférée, chacun desdits trois solides sont choisis parmi l'hydroquinone, le catéchol, le résorcinol, le pyrogallol, le para- méthoxyphénol, le 4-tertiobutylcatéchol et la phénothiazine. Conformément audit second mode, lesdits solides élémentaires utilisés en tant qu'inhibiteur de polymérisation sont préférentiellement choisis parmi les combinaisons ternaires suivantes : HQ-PC-R, HQ-PC-PYRO, HQ-PC-PMP, HQ-PC-TBC, HQ-R-PYRO, HQ-R-PMP, HQ-R-TBC, HQ-PYRO-PMP, HQ-PYRO-TBC, HQ- PMP-TBC, PC-R-PYRO, PC-R-PMP, PC-R-TBC, R-PYRO-PMP, R-PYRO- TBC, R-PMP-TBC, HQ-PMP-PTZ et PYRO-PMP-TBC. More preferably, said solids are selected from hydroquinone (para-dihydroxy-1,4-benzene, denoted HQ in the following description), catechol or pyrocatechol (ortho-dihydroxy-1,2-benzene, noted PC in the following description), resorcinol or resorcinol (meta-dihydroxy-1,3-benzene, noted R in the following description), pyrogallol (1,2,3-trihydroxybenzene, noted PYRO in the following of the description), para-methoxyphenol (or methylhydroquinone, noted PMP in the following description), 4-tert-butylcatechol (or 4-tert-butylpyrocatechol, noted TBC in the following description) and phenothiazine (PTZ noted in the following the description). According to a first particular embodiment of the process according to the invention, said elementary solids used as a polymerization inhibitor are preferably chosen from the following binary combinations: HQ-PC, HQ-R, HQ-PYRO, HQ- PMP, HQ-TBC, PC-R, PC-PYRO, PC-PMP, PC-TBC, R-PYRO, R-PMP, R-TBC, PMP-PYRO, PMP-TBC, TBC-PYRO, and PMP-PTZ . More advantageously, said solids are chosen from the binary combinations: HQ-PC, HQ-R, HQ-PYRO, PC-TBC, and PC-PMP. According to a second particular embodiment of the process according to the invention, said process is carried out in the presence of at least three pulverulent elementary solids each having a role of polymerization inhibitor. Preferably, each of said three solids are selected from hydroquinone, catechol, resorcinol, pyrogallol, para-methoxyphenol, 4-tert-butylcatechol and phenothiazine. According to said second mode, said elementary solids used as a polymerization inhibitor are preferably chosen from the following ternary combinations: HQ-PC-R, HQ-PC-PYRO, HQ-PC-PMP, HQ-PC-TBC, HQ R-PYRO, HQ-R-PMP, HQ-R-TBC, HQ-PYRO-PMP, HQ-PYRO-TBC, HQ-PMP-TBC, PC-R-PYRO, PC-R-PMP, PC-R -TBC, R-PYRO-PMP, R-PYRO-TBC, R-PMP-TBC, HQ-PMP-PTZ and PYRO-PMP-TBC.
Conformément à l'invention, lesdits solides élémentaires sont introduits dans le mélangeur selon tout ratio molaire convenant pour la préparation de ladite composition inhibitrice pulvérulente obtenue selon le procédé de l'invention. According to the invention, said elementary solids are introduced into the mixer at any molar ratio suitable for the preparation of said pulverulent inhibitor composition obtained according to the method of the invention.
En particulier, pour la préparation d'une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de catéchol (HQ-PC), l'hydroquinone et le catéchol sont introduits dans ledit mélangeur dans les proportions suivantes : de 15 à 25 %, de préférence de 18 à 22 %, de manière plus préférée 20 à 22 %, en poids d'hydroquinone et de 75 à 85 %, de préférence de 78 à 82 %, de manière plus préférée de 78 à 80%, en poids de catéchol. Pour la préparation d'une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de résorcinol (HQ-R), l'hydroquinone et le résorcinol sont introduits dans ledit mélangeur dans les proportions suivantes : de 17 à 27 %, de préférence de 20 à 25 %, de manière plus préférée de 21 à 23 %, en poids d'hydroquinone et de 73 à 83 %, de préférence de 75 à 80 %, de manière plus préférée de 77 à 79%, en poids de résorcinol. Pour la préparation d'une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de pyrogallol (HQ-PYRO), l'hydroquinone et le pyrogallol sont introduits dans ledit mélangeur dans les proportions suivantes : de 20 à 30 %, de préférence de 22 à 27 %, de manière plus préférée de 23 à 26 %, en poids d'hydroquinone et de 70 à 80 %, de préférence de 73 à 78 %, de manière plus préférée de 74 à 77 %, en poids de pyrogallol. Pour la préparation d'une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base de catéchol et de para-méthoxyphénol (PC- PMP), le catéchol et le para-méthoxyphénol sont introduits dans ledit mélangeur dans les proportions suivantes : de 23 à 33 %, de préférence de 25 à 30 %, de manière plus préférée de 27 à 29 %, en poids de catéchol et de 67 à 77 %, de préférence de 70 à 75 %, de manière plus préférée de 71 à 73 %, en poids de para-méthoxyphénol. In particular, for the preparation of a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and catechol (HQ-PC), hydroquinone and catechol are introduced into said mixer in the following proportions: from 15 to 25%, preferably 18 to 22%, more preferably 20 to 22%, by weight of hydroquinone and 75 to 85%, preferably 78 to 82%, more preferably 78 to 80%, by weight of catechol. For the preparation of a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and resorcinol (HQ-R), hydroquinone and resorcinol are introduced into said mixer in the following proportions: from 17 to 27%, preferably from 20 to 25%, more preferably from 21 to 23%, by weight of hydroquinone and from 73 to 83%, preferably from 75 to 80%, more preferably preferred from 77 to 79%, by weight of resorcinol. For the preparation of a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and pyrogallol (HQ-PYRO), hydroquinone and pyrogallol are introduced into said mixer in the following proportions: from 20 to 30%, preferably from 22 to 27%, more preferably from 23 to 26%, by weight of hydroquinone and from 70 to 80%, preferably from 73 to 78%, more preferably from 74 to 77%, by weight. of pyrogallol. For the preparation of a pulverulent composition with inhibiting properties comprising a compound based on catechol and para-methoxyphenol (PC-PMP), the catechol and para-methoxyphenol are introduced into said mixer in the following proportions: from 23 to 33 %, preferably 25 to 30%, more preferably 27 to 29%, by weight of catechol and 67 to 77%, preferably 70 to 75%, more preferably 71 to 73%, weight of para-methoxyphenol.
Conformément à ladite étape i) du procédé selon l'invention, lesdits solides élémentaires pulvérulents sont introduits de manière séparée, c'est-à-dire chacun à l'état de corps pur, dans ledit mélangeur. Lesdits solides peuvent être introduits simultanément ou l'un après l'autre dans n'importe quel ordre. Chacun desdits solides peut être introduit progressivement ou non. Préalablement à l'introduction desdits solides, l'enceinte dudit mélangeur est chauffée à une température T inférieure à la température de fusion du solide élémentaire présentant la plus basse température de fusion, ledit solide étant choisi parmi lesdits solides élémentaires mis en œuvre dans le procédé selon l'invention. Ladite température T est inférieure à la température de début de fusion de la composition préparée selon le procédé de l'invention. According to said step i) of the process according to the invention, said powdery elementary solids are introduced separately, that is to say each in the pure state, into said mixer. Said solids can be introduced simultaneously or one after the other in any order. Each of said solids can be introduced gradually or not. Prior to the introduction of said solids, the enclosure of said mixer is heated to a temperature T less than the melting temperature of the elemental solid having the lowest melting temperature, said solid being chosen from said elemental solids used in the process according to the invention. Said temperature T is below the melting start temperature of the composition prepared according to the method of the invention.
En particulier, pour la préparation d'une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de catéchol (HQ-PC), l'enceinte dudit mélangeur est chauffée à une température T avantageusement comprise entre 78 et 85°C, très avantageusement comprise entre 80 et 85°C. Pour la préparation d'une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de résorcinol (HQ-R), l'enceinte dudit mélangeur est chauffée à une température T avantageusement comprise entre 80 et 87°C, très avantageusement comprise entre 82 et 86°C. Pour la préparation d'une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de pyrogallol (HQ-PYRO), l'enceinte dudit mélangeur est chauffée à une température T avantageusement comprise entre 100 et 108°C, très avantageusement comprise entre 102 et 107°C. Pour la préparation d'une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base de catéchol et de para-méthoxyphénol (PC- PMP), l'enceinte dudit mélangeur est chauffée à une température T avantageusement comprise entre 26 et 33°C, très avantageusement comprise entre 28 et 32°C. In particular, for the preparation of a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and catechol (HQ-PC), the enclosure of said mixer is heated to a temperature T advantageously between 78 and 85 ° C. very advantageously between 80 and 85 ° C. For the preparation of a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and resorcinol (HQ-R), the enclosure of said mixer is heated to a temperature T advantageously between 80 and 87 ° C, very advantageously between 82 and 86 ° C. For the preparation of a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and pyrogallol (HQ-PYRO), the enclosure of said mixer is heated to a temperature T advantageously between 100 and 108 ° C, very advantageously between 102 and 107 ° C. For the preparation of a pulverulent composition with inhibiting properties comprising a compound based on catechol and para-methoxyphenol (PC-PMP), the enclosure of said mixer is heated to a temperature T advantageously between 26 and 33 ° C, very advantageously between 28 and 32 ° C.
Lesdites étapes i) et ii) du procédé selon l'invention sont conduites dans un mélangeur. Il s'agit avantageusement d'un mélangeur à socs de charrue, d'un mélangeur à palettes ou d'un mélangeur à ruban(s), ces mélangeurs étant bien connus de l'Homme du métier versé dans le domaine du mélange de poudres. Ledit mélangeur est avantageusement pourvu d'une double enveloppe afin d'assurer les différents transferts thermiques par circulation d'un fluide caloporteur, avantageusement de l'eau ou une huile silicone, dans la double enveloppe. Le fluide caloporteur est maintenu à une température supérieure ou égale à la température T à l'intérieur de l'enceinte dudit mélangeur. Par exemple, le fluide caloporteur est maintenu à une température supérieure de 1 à 5°C à ladite température T. Said steps i) and ii) of the process according to the invention are carried out in a mixer. It is advantageously a mixer with plowshares, a vane mixer or a ribbon mixer (s), these mixers being well known to those skilled in the field of powder mixing. . Said mixer is advantageously provided with a double jacket to ensure the various heat transfers by circulating a coolant, preferably water or a silicone oil, in the jacket. The heat transfer fluid is maintained at a temperature greater than or equal to the temperature T inside the enclosure of said mixer. For example, the coolant is maintained at a temperature greater than 1 to 5 ° C at said temperature T.
Lesdits deux solides élémentaires inhibiteurs de polymérisation sous forme pulvérulente sont introduits de façon séparée dans ledit mélangeur puis y sont mélangés selon ladite étape ii) du procédé selon l'invention. Lesdits solides se présentent par exemple sous forme de cristaux, de granulés ou d'écaillés. On peut en particulier procéder au mélange d'un solide sous forme d'écaillés et d'un solide sous forme de cristaux ou encore au mélange de deux solides sous forme d'écaillés. Said two elementary solids polymerization inhibitors in pulverulent form are introduced separately into said mixer and then mixed therein according to said step ii) of the process according to the invention. Said solids are for example in the form of crystals, granules or flakes. In particular, it is possible to mix a solid in the form of flakes and a solid in the form of crystals or else to mix two solids in the form of flakes.
Conformément au procédé selon l'invention, au moins l'un desdits solides élémentaires inhibiteurs de polymérisation est préalablement chauffé à une température Ti avant d'être introduit dans ledit mélangeur, ladite température Ti étant voisine de ladite température T à laquelle est effectué le mélange selon ladite étape ii). De manière préférée, lesdits solides élémentaires inhibiteurs de polymérisation sont introduits à une température Ti ; lesdits solides peuvent être préalablement chauffés et introduits dans ledit mélangeur à la même température Ti ou à une température Ti légèrement différente. De manière plus précise, ladite température Ti est avantageusement choisie telle que T - 20°C < Ti < T + 20°C. Conformément à ladite étape ii) du procédé selon l'invention, le mélange desdits solides élémentaires inhibiteurs de polymérisation, sous forme pulvérulente, est réalisé en conditions isothermes, c'est-à-dire à température constante, égale à la température T à laquelle l'enceinte du mélangeur a été chauffée, dès l'introduction desdits solides dans ledit mélangeur. Le préchauffage d'au moins l'un des deux desdits solides élémentaires inhibiteurs de polymérisation à une température Ti telle que définie ci-dessus, préférentiellement des deux desdits solides élémentaires inhibiteurs de polymérisation, permet le mélange à température isotherme dans ledit mélangeur. Le mélange est naturellement opéré en phase solide. Ledit mélangeur est avantageusement soumis à une agitation. D'une manière préférée, on choisit les conditions d'agitation de telle sorte qu'il n'y ait pas de cisaillements importants. Ainsi, on préfère une vitesse d'agitation lente. According to the method according to the invention, at least one of said elementary solids polymerization inhibitors is preheated to a temperature Ti before being introduced into said mixer, said temperature Ti being close to said temperature T at which mixing is carried out according to said step ii). In a preferred manner, said elementary polymerization inhibiting solids are introduced at a temperature Ti; said solids may be preheated and introduced into said mixer at the same temperature Ti or at a slightly different temperature Ti. More precisely, said temperature Ti is advantageously chosen such that T - 20 ° C <Ti <T + 20 ° C. According to said step ii) of the process according to the invention, the mixture of said polymerization inhibiting elemental solids, in pulverulent form, is produced under isothermal conditions, that is to say at a constant temperature, equal to the temperature T at which the enclosure of the mixer was heated, as soon as said solids were introduced into said mixer. Preheating at least one of said two polymerization inhibiting elemental solids to a temperature T 1 as defined above, preferably both of said elementary polymerization inhibiting solids, allows isothermal temperature mixing in said mixer. The mixture is naturally operated in the solid phase. Said mixer is advantageously subjected to agitation. In a preferred manner, the stirring conditions are chosen so that there are no significant shears. Thus, a slow stirring speed is preferred.
Le mélangeur est avantageusement placé sous atmosphère inerte durant toute la durée de mise en œuvre du procédé selon l'invention. En particulier, les étapes i) et ii) du procédé selon l'invention sont avantageusement mises en œuvre sous atmosphère inerte, préférentiellement sous azote. Plus avantageusement, lesdites étapes i) et ii) sont mises en œuvre sous atmosphère d'azote humide ou d'azote sec. L'humidification du flux d'azote est avantageusement assurée par barbotage d'azote dans l'eau. Le flux de gaz inerte, préférentiellement d'azote, est avantageusement chauffé à une température égale à T ± 10°C, la température T étant celle à laquelle l'enceinte du mélangeur est chauffée. La quantité d'eau présente dans l'azote représente par exemple de 1 à 5 % poids du poids de l'azote, de préférence de 2 à 3 % poids du poids de l'azote. Par azote sec, on entend un courant d'azote comprenant moins de 0,5 g, de préférence moins de 0,3 g d'eau par kg d'azote. The mixer is advantageously placed under an inert atmosphere throughout the duration of implementation of the method according to the invention. In particular, steps i) and ii) of the process according to the invention are advantageously carried out under an inert atmosphere, preferably under nitrogen. More preferably, said steps i) and ii) are carried out under a wet nitrogen or dry nitrogen atmosphere. The humidification of the nitrogen stream is advantageously ensured by bubbling nitrogen into the water. The flow of inert gas, preferably nitrogen, is advantageously heated to a temperature equal to T ± 10 ° C, the temperature T being that at which the chamber of the mixer is heated. The amount of water present in the nitrogen represents, for example, from 1 to 5% by weight of the weight of the nitrogen, preferably from 2 to 3% by weight of the weight of the nitrogen. Dry nitrogen means a stream of nitrogen comprising less than 0.5 g, preferably less than 0.3 g of water per kg of nitrogen.
Un mode de réalisation préférée de mise en œuvre de ladite étape ii) du procédé selon l'invention consiste à réaliser ledit mélange desdits solides sous atmosphère humide. L'humidité est par exemple assurée par un flux de vapeur sèche, un flux d'azote humide. A preferred embodiment of implementing said step ii) of the method according to the invention consists in producing said mixture of said solids in a humid atmosphere. The humidity is for example ensured by a flow of dry steam, a flow of wet nitrogen.
Le mélange desdits solides élémentaires inhibiteurs de polymérisation conformément à ladite étape ii) du procédé selon l'invention conduit à la transformation desdits solides en ladite composition aux propriétés inhibitrices laquelle est récupérée conformément à ladite étape Ni) du procédé selon l'invention. Ladite étape ii) est réalisée pendant une durée suffisante afin d'obtenir la transformation, préférentiellement la transformation complète, des solides en ladite composition. Cette durée est variable et est notamment fonction des solides élémentaires mis en œuvre et de l'agitation. Mixing said elementary polymerization inhibiting solids according to said step ii) of the process according to the invention leads to the transformation of said solids into said composition with inhibiting properties. which is recovered according to said step Ni) of the method according to the invention. Said step ii) is carried out for a sufficient time in order to obtain the transformation, preferably the complete transformation, of solids into said composition. This duration is variable and is in particular a function of the elementary solids used and the agitation.
Ladite composition est récupérée avant ou après refroidissement. Opéré à l'intérieur ou à l'extérieur dudit mélangeur, le refroidissement de ladite composition obtenue est effectué à une température inférieure à 40°C, de préférence inférieure à 35°C. La borne inférieure de la température de refroidissement est avantageusement la température ambiante. Ladite composition est avantageusement laissée à refroidir à l'intérieur ou à l'extérieur dudit mélangeur. Selon un mode de réalisation particulier, on utilise un système de refroidissement extérieur au mélangeur dans lequel on introduit la composition préparée selon le procédé de l'invention. Said composition is recovered before or after cooling. Operated inside or outside said mixer, the cooling of said composition obtained is carried out at a temperature below 40 ° C, preferably below 35 ° C. The lower limit of the cooling temperature is advantageously ambient temperature. Said composition is advantageously allowed to cool inside or outside said mixer. According to a particular embodiment, a cooling system outside the mixer is used in which the composition prepared according to the method of the invention is introduced.
La composition préparée selon le procédé de l'invention résulte de la transformation des solides élémentaires inhibiteurs de polymérisation mis en œuvre dans ledit procédé en un composé défini. La composition préparée selon le procédé de l'invention est une composition présentant des propriétés inhibitrices sur la polymérisation de monomères, préférentiellement sur la polymérisation radicalaire de monomères à insaturation éthylénique. The composition prepared according to the process of the invention results from the conversion of the elementary polymerization inhibiting solids used in said process into a defined compound. The composition prepared according to the process of the invention is a composition exhibiting inhibiting properties on the polymerization of monomers, preferably on the radical polymerization of ethylenically unsaturated monomers.
La composition préparée selon le procédé de l'invention est une composition pulvérulente, c'est-à-dire qu'elle se présente sous forme de poudre. Par exemple, la composition se présente sous forme d'écaillés, de cristaux, de granulés. The composition prepared according to the process of the invention is a powdery composition, that is to say that it is in powder form. For example, the composition is in the form of flakes, crystals, granules.
La composition préparée selon le procédé de l'invention est encore caractérisée par sa température de fusion notée Tf, laquelle est différente de chacune des températures de fusion de chacun desdits solides élémentaires mis en œuvre dans le procédé selon l'invention et inférieure à la plus basse des températures de fusion des solides mis en œuvre dans le procédé selon l'invention.  The composition prepared according to the process of the invention is further characterized by its melting temperature denoted Tf, which is different from each of the melting temperatures of each of said elementary solids used in the process according to the invention and lower than the most low melting temperatures of the solids used in the process according to the invention.
De manière préférée, ladite composition présente une température de fusion Tf supérieure ou égale à 30°C, de préférence supérieure ou égale à 40°C.  Preferably, said composition has a melting temperature Tf greater than or equal to 30 ° C, preferably greater than or equal to 40 ° C.
En particulier, une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de catéchol (HQ-PC) présente une température de fusion égale à 90±2°C. Une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de résorcinol (HQ-R) présente une température de fusion égale à 91 ±2°C. Une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base d'hydroquinone et de pyrogallol (HQ-PYRO) présente une température de fusion égale à 1 1 1 ±2°C. Une composition pulvérulente aux propriétés inhibitrices comprenant un composé à base de catéchol et de para-méthoxyphénol (PC-PMP) présente une température de fusion égale à 36±2°C. De manière préférée, ladite composition préparée selon le procédé de l'invention est une composition cristallisée. Elle est avantageusement caractérisée par un spectre de diffraction de rayons X qui lui est propre présentant des raies pour des angles 2Θ différents de ceux présentés par les raies figurant sur chacun des spectres de diffraction des rayons X des solides élémentaires dont est issue ladite composition préparée selon le procédé de l'invention. In particular, a pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and catechol (HQ-PC) has a melting temperature equal to 90 ± 2 ° C. A composition powder with inhibiting properties comprising a hydroquinone and resorcinol-based compound (HQ-R) has a melting temperature of 91 ± 2 ° C. A pulverulent composition with inhibiting properties comprising a compound based on hydroquinone and pyrogallol (HQ-PYRO) has a melting temperature of 11 ± 2 ° C. A pulverulent composition with inhibiting properties comprising a compound based on catechol and para-methoxyphenol (PC-PMP) has a melting point of 36 ± 2 ° C. Preferably, said composition prepared according to the process of the invention is a crystallized composition. It is advantageously characterized by an X-ray diffraction spectrum of its own having lines for angles 2Θ different from those presented by the lines appearing on each of the X-ray diffraction spectra of the elementary solids from which said composition prepared according to the process of the invention.
De manière préférée, la composition préparée selon le procédé de l'invention présente une densité apparente (non tassée) plus élevée que celle présentée par chacun des solides élémentaires mis en œuvre dans le procédé selon l'invention. La densité apparente (non tassée) est classiquement mesurée dans un voluménomètre de tassement, par exemple dans un appareil type STAV de Delta Labo. La transformation en phase solide mise en œuvre selon le procédé de l'invention conduit préférentiellement à une densification du mélange opéré selon ladite étape ii) du procédé selon l'invention. Preferably, the composition prepared according to the process of the invention has a bulk density (not packed) higher than that presented by each of the elementary solids used in the process according to the invention. The bulk density (unpacked) is conventionally measured in a compaction volumenometer, for example in a Delta Labo type STAV apparatus. The solid phase transformation implemented according to the process of the invention preferentially leads to a densification of the mixture operated according to said step ii) of the process according to the invention.
De manière très préférée, la composition obtenue selon le procédé de l'invention comprend au moins 80 % en poids, de préférence au moins 90 % en poids d'un composé défini issu d'au moins deux solides élémentaires inhibiteurs de polymérisation. De manière plus préférée, ladite composition obtenue selon le procédé de l'invention est constituée intégralement d'un tel composé. Very preferably, the composition obtained according to the method of the invention comprises at least 80% by weight, preferably at least 90% by weight of a defined compound derived from at least two elementary solids polymerization inhibitors. More preferably, said composition obtained according to the process of the invention consists entirely of such a compound.
Le procédé selon l'invention est un procédé avantageux et simple à mettre en œuvre. En particulier, la conduite du mélange des solides élémentaires inhibiteurs de polymérisation, sous forme de poudre, sous conditions isothermes, c'est-à-dire à température constante, conformément à ladite étape ii) du procédé selon l'invention permet de disposer d'un procédé simplifié dans lequel le préchauffage d'au moins l'un desdits solides élémentaires, de préférence desdits solides élémentaires, évite la mise en place d'une programmation délicate en température. Il en résulte de nombreux avantages et en particulier une régulation en température facilitée pour maintenir constante la température du fluide caloporteur, l'absence de tout risque de fusion du mélange au cours de la mise en oeuvre de ladite étape ii), une productivité améliorée dès lors que les solides élémentaires sont introduits à la température désirée dès qu'ils sont mélangés. De plus, le procédé selon l'invention conduit à la préparation d'une composition présentant généralement directement la granulométrie désirée. The process according to the invention is an advantageous and simple process to implement. In particular, the mixing of the polymerization inhibitor elementary solids, in powder form, under isothermal conditions, ie at a constant temperature, in accordance with said step ii) of the process according to the invention makes it possible to have 'a simplified process in wherein the preheating of at least one of said elementary solids, preferably said elemental solids, avoids the setting up of temperature sensitive programming. This results in numerous advantages and in particular a temperature regulation facilitated to maintain constant the temperature of the heat transfer fluid, the absence of any risk of melting of the mixture during the implementation of said step ii), an improved productivity as soon as possible. when the elementary solids are introduced at the desired temperature as soon as they are mixed. In addition, the process according to the invention leads to the preparation of a composition generally having directly the desired particle size.
La composition préparée selon le procédé de l'invention est avantageusement utilisée en tant que composition inhibitrice pour l'arrêt immédiat de polymérisations de monomères, préférentiellement de polymérisations radicalaires de monomères présentant au moins une insaturation éthylénique. En particulier, elle est très avantageusement utilisée pour la stabilisation desdits monomères en cours de fabrication et de purification. Elle est encore très avantageusement utilisée pour terminer instantanément la polymérisation non-désirée de monomères lors du transport et/ou du stockage de mélange contenant lesdits monomères. L'utilisation de ladite composition préparée selon le procédé de l'invention pour l'arrêt immédiat de la polymérisation d'un ou plusieurs monomère(s), préférentiellement de la polymérisation radicalaire d'un ou plusieurs monomère(s) présentant au moins une insaturation éthylénique, est mise en œuvre par l'addition au(x)dit(s) monomère(s) d'une quantité efficace d'une composition obtenue selon le procédé de l'invention. La quantité de ladite composition à ajouter pour obtenir une inhibition efficace de la polymérisation varie dans une large mesure. Elle est fonction du(es) monomère(s) à stabiliser et des conditions opératoires auxquelles est(sont) soumis le(s)dit(s) monomère(s). Il va de soi qu'à des températures élevées, la quantité de ladite composition inhibitrice sera plus importante. Ainsi la quantité de ladite composition sera à évaluer au cas par cas. A titre indicatif, une quantité totale de ladite composition préparée selon le procédé de l'invention comprise entre 1 et 2000 ppm, de préférence entre 10 et 2000 ppm suffit généralement, cette quantité étant exprimée par rapport au poids total du(es) monomère(s) à stabiliser. The composition prepared according to the process of the invention is advantageously used as an inhibiting composition for the immediate termination of polymerizations of monomers, preferably radical polymerizations of monomers having at least one ethylenic unsaturation. In particular, it is very advantageously used for the stabilization of said monomers during manufacture and purification. It is still very advantageously used to instantly terminate the undesired polymerization of monomers during transport and / or storage of mixture containing said monomers. The use of said composition prepared according to the process of the invention for immediately stopping the polymerization of one or more monomer (s), preferably the radical polymerization of one or more monomers (s) having at least one ethylenic unsaturation is implemented by the addition to said said monomer (s) of an effective amount of a composition obtained according to the method of the invention. The amount of said composition to be added to achieve effective inhibition of polymerization varies to a large extent. It is a function of the monomer (s) to be stabilized and the operating conditions to which the said monomer (s) are (are) subjected. It goes without saying that at high temperatures, the amount of said inhibiting composition will be greater. Thus the quantity of said composition will be evaluated on a case by case basis. As a guide, a total amount of said composition prepared according to the process of the invention of between 1 and 2000 ppm, preferably between 10 and 2000 ppm, is generally sufficient, this amount being expressed relative to the total weight of the (es) monomer ( s) to stabilize.
Les monomères présentant au moins une insaturation éthylénique, dont la polymérisation est immédiatement arrêtée en présence de la composition obtenue selon le procédé de l'invention, sont avantageusement choisis parmi les monomères aromatiques à insaturation éthylénique et les monomères aliphatiques à insaturation éthylénique. The monomers exhibiting at least one ethylenic unsaturation, the polymerization of which is stopped immediately in the presence of the composition obtained according to the process of the invention, are advantageously chosen from aromatic monomers with ethylenic unsaturation and aliphatic monomers with ethylenic unsaturation.
Parmi les monomères aromatiques à insaturation éthylénique, le styrène, α- méthylstyrène, le vinyltoluène, le divinylbenzène, le vinylnaphtalène et les acides styrènesulfoniques sont préférés.  Of the aromatic ethylenically unsaturated monomers, styrene, α-methylstyrene, vinyltoluene, divinylbenzene, vinylnaphthalene and styrenesulfonic acids are preferred.
Parmi les monomères aliphatiques à insaturation éthylénique, les monomères oléfiniques comprenant une ou deux insaturations, les monomères insaturés halogénés, les acides insaturés, les esters insaturés, les résines insaturées, les amides insaturés, les nitriles insaturés, les éthers insaturés sont préférés. En particulier, lesdits monomères aliphatiques à insaturation éthylénique sont préférentiellement choisis parmi l'isoprène, le butadiène, le chlorure de vinyle, le chloroprène, le chlorure de vinylidène, le fluorure de vinylidène, le fluorure de vinyle, l'acide acrylique, l'acide méthacrylique, l'acide crotonique, les esters insaturés de l'acide acrylique, tels que l'acrylate de méthyle, l'acrylate d'éthyle, l'acrylate de butyle, l'acrylate de 2-éthylhexyle, l'acrylate de 2-hydroxyéthyle, l'acrylate d'hydroxypropyle, les esters insaturés de l'acide méthacrylique tel que le méthacrylate de méthyle, le méthacrylate de butyle, le méthacrylate de lauryle, le méthacrylate de diméthylaminoéthyle, le méthacrylate de stéaryle, l'acétate de vinyle, les résines époxy acrylées et le diacrylate de polyéthylèneglycol, l'acrylamide, le Ν,Ν-diméthylacrylamide, le méthylènebisacrylamide et la N-vinylpyrrolidone, l'acrylonitrile, l'éther de vinyle et de méthyle, les vinylpyridines, le vinylphosphonate de diéthyle.  Among the ethylenically unsaturated aliphatic monomers, olefinic monomers comprising one or two unsaturations, halogenated unsaturated monomers, unsaturated acids, unsaturated esters, unsaturated resins, unsaturated amides, unsaturated nitriles, unsaturated ethers are preferred. In particular, said ethylenically unsaturated aliphatic monomers are preferably chosen from isoprene, butadiene, vinyl chloride, chloroprene, vinylidene chloride, vinylidene fluoride, vinyl fluoride, acrylic acid, and the like. methacrylic acid, crotonic acid, unsaturated esters of acrylic acid, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylate, 2-hydroxyethyl, hydroxypropyl acrylate, unsaturated esters of methacrylic acid such as methyl methacrylate, butyl methacrylate, lauryl methacrylate, dimethylaminoethyl methacrylate, stearyl methacrylate, vinyl, acrylated epoxy resins and polyethylene glycol diacrylate, acrylamide, Ν, Ν-dimethylacrylamide, methylenebisacrylamide and N-vinylpyrrolidone, acrylonitrile, methyl vinyl ether, vinylpyridines, diethyl vinylphosphonate.
Les propriétés inhibitrices de la composition obtenue selon le procédé de l'invention sur la polymérisation des monomères sont appréciées au regard d'un test qui détermine le temps d'induction. Ladite composition empêche la polymérisation jusqu'à un certain temps au-delà duquel la réaction de polymérisation démarre normalement. Ce temps est appelé temps d'induction. Plus il est long, plus l'inhibition est efficace. The inhibitory properties of the composition obtained according to the method of the invention on the polymerization of the monomers are evaluated with regard to a test which determines the induction time. The composition prevents polymerization for a period of time beyond which the polymerization reaction normally starts. This time is called induction time. The longer it is, the more effective the inhibition.
Afin d'évaluer les propriétés d'inhibition de la composition préparée selon le procédé de l'invention, vis-à-vis de la polymérisation radicalaire de monomères à insaturation éthylénique, des tests d'inhibition avec le méthacrylate de méthyle (MMA) sont mis en ouvre avec le protocole suivant. L'efficacité de la composition préparée selon le procédé de l'invention pour le méthacrylate de méthyle est déterminée par la mesure du temps d'induction qui représente le temps au bout duquel le monomère commence à polymériser lorsqu'il est chauffé dans un bain à température régulée et en présence d'un initiateur. Ce temps d'induction correspond au temps au bout duquel apparaît une exothermie visible qui indique le début de polymérisation. Le protocole pour déterminer le temps d'induction est le suivant : In order to evaluate the inhibition properties of the composition prepared according to the process of the invention, with respect to the radical polymerization of ethylenically unsaturated monomers, inhibition tests with methyl methacrylate (MMA) are implemented with the following protocol. The effectiveness of the composition prepared according to the process of the invention for methyl methacrylate is determined by measuring the induction time which represents the time at which the monomer begins to polymerize when heated in a hot water bath. regulated temperature and presence of an initiator. This induction time corresponds to the time at the end of which appears a visible exotherm which indicates the beginning of polymerization. The protocol for determining the induction time is as follows:
1 - on prépare une solution A à base de méthacrylate de méthyle pur (MMA) contenant 2000 ppm d'un solide inhibiteur.  1 - A solution is prepared based on pure methyl methacrylate (MMA) containing 2000 ppm of an inhibiting solid.
2- on prépare une solution B à base de méthacrylate de méthyle pur (MMA) contenant 200 ppm d'un initiateur.  2- a solution B is prepared based on pure methyl methacrylate (MMA) containing 200 ppm of an initiator.
3- on dilue 0,2 g de la solution A dans 19,8 g de la solution B de manière à obtenir une solution C ayant une teneur en inhibiteur égale à 20 ppm.  3- dilute 0.2 g of solution A in 19.8 g of solution B so as to obtain a solution C having an inhibitor content equal to 20 ppm.
4- 3 g de la solution C sont placés dans un tube équipé d'un thermomètre. Le tube est placé dans un bain d'huile thermostaté à 80°C ± 0,01 °C. 4-3 g of solution C are placed in a tube equipped with a thermometer. The tube is placed in an oil bath thermostated at 80 ° C ± 0.01 ° C.
5- la température dans le tube est relevée en continu jusqu'à ce qu'elle commence à augmenter (augmentation de l'ordre de 0,3°C). 5- the temperature in the tube is raised continuously until it begins to increase (increase of the order of 0.3 ° C).
6. le moment où l'exothermie est observée correspond au temps d'induction. 6. the moment the exotherm is observed corresponds to the induction time.
Le temps d'induction correspond à l'exothermie visible qui indique le début de la polymérisation du MMA. La courbe de variation de température ΔΤ en fonction du temps est enregistrée en continu. Plus le temps d'induction est grand, plus la composition inhibitrice testée est efficace à concentration pondérale constante. Le temps d'induction ainsi déterminé est comparé à celui obtenu en testant un mélange qui contient un initiateur mais qui ne contient pas de composition inhibitrice. The induction time corresponds to the visible exotherm which indicates the beginning of the MMA polymerization. The temperature variation curve ΔΤ as a function of time is recorded continuously. The greater the induction time, the more effective the inhibitory composition tested is at constant weight concentration. The induction time thus determined is compared with that obtained by testing a mixture which contains an initiator but which does not contain an inhibiting composition.
Les caractéristiques physico-chimiques des compositions préparées selon le procédé de l'invention sont déterminées selon les méthodes suivantes : The physico-chemical characteristics of the compositions prepared according to the method of the invention are determined according to the following methods:
1 . Point de fusion ou température de fusion. 1. Melting point or melting temperature.
Le point de fusion ou température de fusion de la composition préparée selon le procédé de l'invention est mesuré par analyse calorimétrique différentielle. La mesure est effectuée à l'aide d'un analyseur différentiel Mettler DSC822e dans les conditions suivantes :  The melting point or melting temperature of the composition prepared according to the method of the invention is measured by differential scanning calorimetry. The measurement is carried out using a Mettler differential analyzer DSC822e under the following conditions:
- préparation de l'échantillon à température ambiante, préférentiellement sous atmosphère inerte : pesée et introduction dans un porte échantillon,  - Preparation of the sample at room temperature, preferably under an inert atmosphere: weighing and introduction into a sample holder,
- porte échantillon : capsule en aluminium sertie,  - sample holder: crimped aluminum capsule,
- prise d'essai : 5 à 10 mg,  - test portion: 5 to 10 mg,
- vitesse de montée en température : 2-10°C/min,  - temperature rise rate: 2-10 ° C / min,
- plage d'étude : 10 - 220°C. On pèse l'échantillon de la composition qui est introduite dans la capsule qui est sertie puis placée dans l'appareil. - study range: 10 - 220 ° C. We weigh the sample of the composition which is introduced into the capsule which is crimped and placed in the apparatus.
On lance la programmation de température et l'on obtient le profil de fusion sur un thermogramme.  The temperature programming is started and the fusion profile is obtained on a thermogram.
La température de fusion est définie à partir d'un thermogramme réalisé dans les conditions opératoires précédentes. The melting temperature is defined from a thermogram produced under the preceding operating conditions.
On retient la température onset : température correspondant à la pente maximale du pic de fusion. 2. Spectre de diffraction des rayons X.  The onset temperature is selected: temperature corresponding to the maximum slope of the melting peak. 2. X-ray diffraction spectrum.
Le spectre de diffraction des rayons X de la composition préparée selon le procédé de l'invention est déterminé à l'aide de l'appareil X'Pert Pro MPD PANalytical équipé d'un détecteur X' Celerator, dans les conditions suivantes :  The X-ray diffraction spectrum of the composition prepared according to the process of the invention is determined using the X'Pert Pro MPD PANalytical device equipped with an X 'Celerator detector, under the following conditions:
- Start Position [°2Th.] : 1 ,5124  - Start Position [° 2Th.]: 1, 5124
- End Position [°2Th.] : 49,9794  - End Position [° 2Th.]: 49.9794
- Step Size [°2Th.] : 0,0170  - Step Size [° 2Th.]: 0.0170
- Scan Step Time [s] : 41 ,0051  - Scan Step Time [s]: 41, 0051
- Anode Material : Cu  - Anode Material: Cu
- K-Alpha1 [Â] : 1 ,54060  K-Alpha1 [?]: 1, 54060
- Generator Settings : 30 mA, 40 kV  - Generator Settings: 30 mA, 40 kV
On donne ci-après un exemple illustrant la présente invention sans caractère limitatif. Exemple 1 : An example is given below illustrating the present invention without limitation. Example 1
On réalise la préparation d'un composé défini à base de catéchol et de para- méthoxyphénol (PC-PMP) dans un mélangeur horizontal à cuve cylindrique d'un volume total utile de 6 litres, équipé d'un arbre d'agitation type à socs de charrue et à vitesse variable. La cuve du mélangeur est munie d'une double-enveloppe dans laquelle circule un fluide caloporteur constitué d'eau assurant la régulation de température du mélangeur.  The preparation of a defined compound based on catechol and para-methoxyphenol (PC-PMP) is carried out in a horizontal mixer with a cylindrical tank with a total useful volume of 6 liters, equipped with a stirring shaft type with plowshares and variable speed. The mixer tank is provided with a double jacket in which circulates a coolant consisting of water ensuring the temperature control of the mixer.
Les températures caloporteur entrée/sortie, ainsi que la température interne du mélangeur sont mesurées par sonde Pt (100 Ω à 0°C) régulées et enregistrées durant tout le procédé.  The inlet / outlet coolant temperatures, as well as the internal temperature of the mixer are measured by Pt probe (100 Ω at 0 ° C) regulated and recorded throughout the process.
Le mélangeur est préchauffé pendant une heure à une température de 32°C +/- 1 °C, en maintenant la double-enveloppe à une température de 34°C +/-1 °C pour compenser les pertes thermiques. Le mélangeur est balayé par un débit d'azote sec de 240 litres par heure. Le granulateur fonctionne à pression atmosphérique. Lèvent du granulateur est équipé d'un filtre à poche. The mixer is preheated for one hour at a temperature of 32 ° C +/- 1 ° C, maintaining the jacket at a temperature of 34 ° C +/- 1 ° C to compensate for heat losses. The mixer is swept by a nitrogen flow dry of 240 liters per hour. The granulator operates at atmospheric pressure. Lift granulator is equipped with a bag filter.
Les cristaux de catéchol et de para-méthoxyphénol sont préchauffés indépendamment dans une étuve permettant d'obtenir une température homogène pour chacun des solides : 2,271 kg de para-méthoxyphénol (PMP) sont préchauffés à une température de 35°C +/-1 °C dans une étuve et 0,883 kg de catéchol (PC) sont préchauffés à une température de 46,3°C +/-1 °C dans une autre étuve.  The catechol and para-methoxyphenol crystals are preheated independently in an oven to obtain a homogeneous temperature for each of the solids: 2,271 kg of para-methoxyphenol (PMP) are preheated to a temperature of 35 ° C +/- 1 ° C in an oven and 0.883 kg of catechol (PC) are preheated to a temperature of 46.3 ° C +/- 1 ° C in another oven.
Après préchauffage du mélangeur à 32°C +/- 1 °C, le para-méthoxyphénol (PMP) préchauffé est introduit dans le mélangeur puis on y introduit ensuite le catéchol préchauffé. Le mélange est endothermique (de l'ordre de 2 kcal/kg de mélange). L'agitation du mélangeur est mise en service à la vitesse de 100 tours/min durant 5 minutes. Puis l'agitation est réduite à une vitesse de 40 tours/min et est maintenue pendant 45 minutes. La température au sein du mélangeur est voisinde de 32°C durant toute la durée d'agitation au crours de la transformation. On réalise ensuite une étape de refroidissement en portant le fluide caloporteur à 15°C dans la double enveloppe. La durée de refroidissement est de l'ordre de 30 minutes et le composé est ainsi refroidi jusqu'à une température de 22°C +/- 1 °C. L'agitation dans le mélangeur et la circulation d'azote sont stoppées.  After preheating the mixer at 32 ° C +/- 1 ° C, the pre-heated para-methoxyphenol (PMP) is introduced into the mixer and then introduced the preheated catechol. The mixture is endothermic (of the order of 2 kcal / kg of mixture). The agitation of the mixer is put into operation at a speed of 100 rpm for 5 minutes. Then stirring is reduced at a speed of 40 rpm and is maintained for 45 minutes. The temperature in the mixer is around 32 ° C throughout the stirring period during the transformation. A cooling step is then carried out by bringing the coolant to 15 ° C in the jacket. The cooling time is of the order of 30 minutes and the compound is thus cooled to a temperature of 22 ° C +/- 1 ° C. The agitation in the mixer and the nitrogen circulation are stopped.
On vidange alors le mélangeur et on récupère le composé défini résultant du mélange de PC et PMP. Le composé obtenu est un composé pulvérulent. Il présente une densité apparente (non tassée) égale à 0,82 +/- 0,01 et un point de fusion de 36,7°C +/-1 °C. The mixer is then emptied and the defined compound resulting from the mixture of PC and PMP is recovered. The compound obtained is a powdery compound. It has a bulk density (unpacked) of 0.82 +/- 0.01 and a melting point of 36.7 ° C +/- 1 ° C.

Claims

REVENDICATIONS
1 . Procédé de préparation d'une composition pulvérulente présentant des propriétés inhibitrices sur la polymérisation de monomères et ayant une température de fusion Tf comprenant : 1. A process for preparing a powdery composition having inhibiting properties on the polymerization of monomers and having a melting temperature Tf comprising:
i) l'introduction dans un mélangeur dont l'enceinte a été préalablement chauffée à une température T inférieure à Tf d'au moins deux solides élémentaires inhibiteurs de polymérisation, lesdits solides étant introduits séparément dans ledit mélangeur sous forme pulvérulente,  i) introducing into a mixer whose chamber has been heated beforehand to a temperature T less than Tf of at least two elementary polymerization inhibiting solids, said solids being introduced separately into said mixer in pulverulent form,
ii) le mélange dans ledit mélangeur, en l'absence de toute phase liquide extérieure, desdits solides à une température T inférieure à la température Tf, au moins l'un desdits solides élémentaires inhibiteurs de polymérisation étant introduit dans ledit mélangeur à une température Ti telle que le mélange se réalise en conditions isothermes à une température fixée à ladite température T, et  ii) mixing in said mixer, in the absence of any external liquid phase, said solids at a temperature T below the temperature Tf, at least one of said elementary polymerization-inhibiting solids being introduced into said mixer at a temperature Ti such that the mixing is carried out under isothermal conditions at a temperature set at said temperature T, and
iii) la récupération de ladite composition pulvérulente.  iii) recovering said powdery composition.
2. Procédé de préparation selon la revendication 1 dans lequel lesdits solides élémentaires présentent une température de fusion supérieure ou égale à 50°C. 2. Preparation process according to claim 1 wherein said elementary solids have a melting temperature greater than or equal to 50 ° C.
3. Procédé de préparation selon la revendication 1 ou la revendication 2 dans lequel lesdits solides élémentaires présentent une température de fusion supérieure ou égale à 100°C. 3. Preparation process according to claim 1 or claim 2 wherein said elementary solids have a melting temperature greater than or equal to 100 ° C.
4. Procédé de préparation selon l'une des revendications 1 à 3 dans lequel lesdits solides sont constitués d'une molécule présentant au moins un noyau benzénique et au moins un hétéroatome choisi parmi l'azote, l'oxygène et le soufre. 4. Preparation process according to one of claims 1 to 3 wherein said solids consist of a molecule having at least one benzene ring and at least one heteroatom selected from nitrogen, oxygen and sulfur.
5. Procédé de préparation selon la revendication 4 dans lequel lesdits solides sont constitués d'une molécule présentant au moins un noyau benzénique portant au moins un radical hydroxyle -OH. 5. Preparation process according to claim 4 wherein said solids consist of a molecule having at least one benzene ring bearing at least one hydroxyl radical -OH.
6. Procédé de préparation selon l'une des revendications 1 à 4 dans lequel lesdits solides sont choisis parmi l'hydroquinone (HQ), le catéchol (PC), le résorcinol (R), le pyrogallol (PYRO), le para-méthoxyphénol (PMP), le 4- tertiobutylcatéchol (TBC) et la phénothiazine (PTZ). 6. Preparation process according to one of claims 1 to 4 wherein said solids are selected from hydroquinone (HQ), catechol (PC), resorcinol (R), pyrogallol (PYRO), para-methoxyphenol (PMP), 4-tert-butylcatechol (TBC) and phenothiazine (PTZ).
7. Procédé de préparation selon la revendication 6 dans lequel lesdits solides élémentaires sont choisis parmi les combinaisons binaires suivantes : HQ-PC, HQ-R, HQ-PYRO, HQ-PMP, HQ-TBC, PC-R, PC-PYRO, PC-PMP, PC-TBC, R-PYRO, R-PMP, R-TBC, PMP-PYRO, PMP-TBC, TBC-PYRO et PMP-PTZ. 7. Preparation process according to claim 6 wherein said elementary solids are selected from the following bit combinations: HQ-PC, HQ-R, HQ-PYRO, HQ-PMP, HQ-TBC, PC-R, PC-PYRO, PC-PMP, PC-TBC, R-PYRO, R-PMP, R-TBC, PMP-PYRO, PMP-TBC, TBC-PYRO and PMP-PTZ.
8. Procédé de préparation selon l'une des revendications 1 à 6 tel qu'il est mis en œuvre en présence d'au moins trois solides élémentaires pulvérulents présentant chacun un rôle d'inhibiteur de polymérisation. 8. Preparation process according to one of claims 1 to 6 as it is implemented in the presence of at least three powdery elementary solids each having a role of polymerization inhibitor.
9. Procédé de préparation selon l'une des revendications 1 à 8 dans lequel lesdits solides élémentaires pulvérulents sont introduits à une température Ti, ladite température Ti étant choisie telle que T - 20°C < Ti < T + 20°C. 9. Preparation process according to one of claims 1 to 8 wherein said powdery elementary solids are introduced at a temperature Ti, said temperature Ti being chosen such that T - 20 ° C <Ti <T + 20 ° C.
10. Procédé de préparation selon l'une des revendications 1 à 9 tel que ladite composition pulvérulente présentant des propriétés inhibitrices présente une température de fusion Tf supérieure ou égale à 30°C. 10. Preparation process according to one of claims 1 to 9 such that said powdery composition having inhibiting properties has a melting temperature Tf greater than or equal to 30 ° C.
1 1 . Utilisation de ladite composition préparée selon le procédé selon l'une des revendications 1 à 10 en tant que composition inhibitrice pour l'arrêt immédiat de polymérisations radicalaires de monomères présentant au moins une insaturation éthylénique. 1 1. Use of said composition prepared according to the method according to one of claims 1 to 10 as inhibiting composition for the immediate termination of radical polymerizations of monomers having at least one ethylenic unsaturation.
12. Utilisation selon la revendication 1 1 telle que lesdits monomères présentant au moins une insaturation éthylénique sont choisis parmi les monomères aromatiques à insaturation éthylénique et les monomères aliphatiques à insaturation éthylénique. 12. Use according to claim 1 1 such that said monomers exhibiting at least one ethylenic unsaturation are chosen from aromatic monomers containing ethylenic unsaturation and aliphatic monomers containing ethylenic unsaturation.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017041204A1 (en) 2015-09-07 2017-03-16 Rhodia Operations Use of polymerization inhibitor compositions
US9687020B2 (en) 2011-08-25 2017-06-27 Rhodia Operations Method for preparing an aromatic composition including a compound containing two solids having organoleptic properties

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021022550A1 (en) * 2019-08-08 2021-02-11 Rhodia Operations Polymerization inhibitor compositions and uses thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2478710A (en) * 1945-12-21 1949-08-09 Standard Oil Dev Co Method of stabilizing hydrocarbons
EP0403672A1 (en) * 1987-12-22 1990-12-27 Mitsubishi Petrochemical Co., Ltd. Method of inhibiting polymerization of styrenes
US6339177B1 (en) * 2000-05-24 2002-01-15 Sea Lion Technology, Inc. Dinitroalkyl aromatics polymerization retarders or inhibitors and methods for making and for using same
US6518374B1 (en) 1999-04-27 2003-02-11 Basf Aktiengesellschaft Method of immediately terminating free-radical polymerisation processes

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6960279B2 (en) * 2002-05-06 2005-11-01 Fina Technology, Inc. Method for stabilizing vinyl aromatic monomers using selected polymerization inhibitors and polymers prepared therewith
KR20060053284A (en) * 2004-10-13 2006-05-19 로레알 Use for the cosmetic treatment of keratin materials of a film-forming composition comprising an electrophilic monomer and a non-silicone polymer, which gives a rigid coat
US7553896B2 (en) * 2005-06-17 2009-06-30 Chemtura Corporation Ortho-nitrosophenols as polymerization inhibitors

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2478710A (en) * 1945-12-21 1949-08-09 Standard Oil Dev Co Method of stabilizing hydrocarbons
EP0403672A1 (en) * 1987-12-22 1990-12-27 Mitsubishi Petrochemical Co., Ltd. Method of inhibiting polymerization of styrenes
US6518374B1 (en) 1999-04-27 2003-02-11 Basf Aktiengesellschaft Method of immediately terminating free-radical polymerisation processes
US6339177B1 (en) * 2000-05-24 2002-01-15 Sea Lion Technology, Inc. Dinitroalkyl aromatics polymerization retarders or inhibitors and methods for making and for using same

Non-Patent Citations (8)

* Cited by examiner, † Cited by third party
Title
DHILLON M S: "Solid + liquid phase diagrams of mixtures containing phenol, cresols and dihydroxyphenols", ZEITSCHRIFT FUER PHYSIKALISCHE CHEMIE, GEEST & PORTIG, LEIPZIG, DE, vol. 259, no. 2, 1 January 1978 (1978-01-01), pages 243 - 248, XP009155185, ISSN: 0323-4479 *
M. S. DHILLON, Z. PHYS. CHEMIE, vol. 259, no. 2, 1978, pages 243 - 248
MING-JER LEE ET AL., J. CHEM. ENG. DATA, vol. 42, 1997, pages 349 - 352
MING-JER LEE ET AL: "Solid-Liquid Equilibria for 4-Methoxyphenol with Catechol, Ethylenediamine, or Piperazine", JOURNAL OF CHEMICAL & ENGINEERING DATA, vol. 42, no. 2, 1 March 1997 (1997-03-01), pages 349 - 352, XP055023863, ISSN: 0021-9568, DOI: 10.1021/je960201b *
PIERRE SENDEN: "Recherche du point eutectique ternaire des trois systèmes : Résorcine, Nitronaphtaline alpha, Pyrocatéchine, Hydroquinone, Résorcine, Pyrocatéchine, Hydroquinone, Nitronaphtaline alpha, Pyrocatéchine", BULLETIN DE LA SOCIÉTÉ CHIMIQUE DE BELGIQUE, SOCIÉTÉ CHIMIQUE DE BELGIQUE, BELGIQUE, vol. 32, 1 January 1923 (1923-01-01), pages 281 - 285, XP009155229, ISSN: 0374-6585 *
RAI U S ET AL: "Chemistry of organic eutectics and 1:1 addition compound: p-phenylenediamine-catechol system", THERMOCHIMICA ACTA, ELSEVIER SCIENCE PUBLISHERS, AMSTERDAM, NL, vol. 138, no. 2, 15 February 1989 (1989-02-15), pages 219 - 231, XP026537146, ISSN: 0040-6031, [retrieved on 19890215], DOI: 10.1016/0040-6031(89)87258-2 *
SHARMA B L ET AL: "Microstructures of binary organic eutectics", JOURNAL OF CRYSTAL GROWTH, ELSEVIER, AMSTERDAM, NL, vol. 67, no. 3, 1 August 1984 (1984-08-01), pages 633 - 638, XP024421083, ISSN: 0022-0248, [retrieved on 19840801], DOI: 10.1016/0022-0248(84)90059-9 *
U. S. RAI ET AL: "Solidification behaviour of organic eutectics and 1:1 addition compound: p-Phenylenediamine-resorcinol system", CRYSTAL RESEARCH AND TECHNOLOGY, vol. 23, no. 7, 1 July 1988 (1988-07-01), pages 871 - 880, XP055024739, ISSN: 0232-1300, DOI: 10.1002/crat.2170230706 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9687020B2 (en) 2011-08-25 2017-06-27 Rhodia Operations Method for preparing an aromatic composition including a compound containing two solids having organoleptic properties
WO2017041204A1 (en) 2015-09-07 2017-03-16 Rhodia Operations Use of polymerization inhibitor compositions
JP2018527359A (en) * 2015-09-07 2018-09-20 ローディア オペレーションズ Use of polymerization inhibitor composition
EP3347333A4 (en) * 2015-09-07 2019-04-10 Rhodia Operations Use of polymerization inhibitor compositions
US10766848B2 (en) 2015-09-07 2020-09-08 Rhodia Operations Use of polymerization inhibitor compositions

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