摘要:
Procédé de production de produits en PVP-H2O2 sous forme de poudres coulantes ou d'un solide ou une mousse poreux et libre. Pour préparer des poudres coulantes, on maintient un lit fluidisé à une température réactionnelle comprise entre à peu près la température ambiante et 60 °C, puis on le met en contact avec des gouttelettes finement divisées d'une solution aqueuse de H2O2 de 30 à 85 % en poids. De préférence, la température du lit fluidisé est comprise entre environ 35 et 45 °C, on utilise une solution de H2O2 de 5 à 70 %, et l'on introduit la solution de H2O2 à une vitesse d'environ 5 à 50 grammes par minute par kilogramme de PVP. De préférence, le produit en PVP-H2O2 contient environ de 15 à 24 %, et de préférence de 18 à 22 %, de H2O2 (rapport molaire 1:1) et une quantité d'eau inférieure à environ 5 %.
摘要:
A composition for preventing or retarding the formation of gas hydrates or for reducing the tendency of gas hydrates to agglomerate, during the transport of a fluid comprising water and a hydrocarbon, through a conduit, comprising, (a) a polymer or copolymer selected from a terpolymer of vinyl pyrrolidone, vinyl caprolactam and an ammonium derivative monomer having from 6 to 12 carbon atoms, selected from the group consisting of dialkyl aminoalkyl methacrylamide, dialkyl dialkenyl ammonium halide and a dialkylamino alkyl acrylate or methacrylate, a copolymer of vinyl pyrrolidone and vinyl caprolactam, and a homopolymer of vinyl caprolactam, and (b) an alcohol containing three to five carbon atoms and one hydroxy group, or a low molecular weight glycol ether containing an alkoxy group having at least 3 carbon atoms.
摘要:
What is described herein is a process for making a copolymer of high specific viscosity by polymerisation of maleic anhydride and a C1-C4 alkyl vinyl ether monomer. The invention involves polymerizing said monomers to form a slurry of said copolymer in excess alkyl vinyl ether as solvent and toluene or an aliphatic organic compound as cosolvent, and is characterized by the steps of: (a) precharging a reactor with C1-C4 alkyl vinyl ether as solvent at a reaction temperature, (b) feeding a mixture of maleic anhydride and a C1-C4 alkyl vinyl ether in substantially stoichiometric amounts, preferably with a slight excess of the alkyl vinyl ether, and at a selected rate, into said precharged reactor, and (c) simultaneously feeding a predetermined mixture of toluene or an aliphatic organic compound and a polymerization initiator continuously over substantially the entire period of polymerization.
摘要:
Procédé de production d'un polymère d'éther vinylique d'alkyle inférieur/d'anhydride maléique dépourvu de benzène et présentant une viscosité spécifique comprise entre 1,0 et 5,5 environ, et qui consiste à prémélanger l'anhydride maléique et l'éther vinylique d'alkyle en un rapport molaire compris entre environ 1:1,1 et environ 1:2, dans un mélange de co-solvants constitué de benzène substitué par alkyle inférieur, d'un alcane C6-8, d'un éther d'alkyle inférieur saturé, avec un éther vinylique d'alkyle inférieur comme co-solvant, et à mettre en réaction le mélange monomère transformé en complexe à une température et une pression élevées et en contact continu avec une amorce peroxyde. La viscosité spécifique est régulée lorsqu'on ajuste la quantité d'éther vinylique d'alkyle inférieur dans le mélange de co-solvants. Le produit polymère est récupéré de la bouillie obtenue par séchage sous vide.
摘要:
A composition for preventing or retarding the formation of gas hydrates or for reducing the tendency of gas hydrates to agglomerate, during the transport of a fluid comprising water and a hydrocarbon, through a conduit, comprising, (a) a polymer or copolymer selected from a terpolymer of vinyl pyrrolidone, vinyl caprolactam and an ammonium derivative monomer having from 6 to 12 carbon atoms, selected from the group consisting of dialkyl aminoalkyl methacrylamide, dialkyl dialkenyl ammonium halide and a dialkylamino alkyl acrylate or methacrylate, a copolymer of vinyl pyrrolidone and vinyl caprolactam, and a homopolymer of vinyl caprolactam, and (b) an alcohol containing three to five carbon atoms and one hydroxy group, or a low molecular weight glycol ether containing an alkoxy group having at least 3 carbon atoms.
摘要:
On décrit un procédé de fabrication d'un copolymère présentant une viscosité spécifique élevée, par polymérisation d'anhydride maléique et d'un monomère d'éther vinyl-alkyle C1-C4. L'invention consiste à polymériser lesdits monomères pour former une pâte dudit copolymère dans un excédent d'éther vinyl-alkyle comme solvant et du toluène ou un composé organique aliphatique comme co-solvant et se caractérise par les étapes suivantes: a) précharger un réacteur avec de l'éther vinyl-alkyle C1-C4 comme solvant à une température de réaction, b) alimenter ledit réacteur préchargé en un mélange d'anhydride maléique et d'un éther vinyl-alkyle C1-C4 en quantités pratiquement stoechiométriques, de préférence avec un léger excédent d'éther vinyl-alkyle, et à une vitesse choisie, et c) alimenter le réacteur simultanément et continuellement en un mélange prédéterminé de toluène ou d'un composé organique aliphatique et d'une substance amorçant la polymérisation pendant pratiquement toute la durée de la polymérisation.
摘要:
This invention relates to a process for the purification of a crude liquid N-vinylpyrrolidone product which comprises (I) product rectification by (a) subjecting said crude product containing at least 0.3 weight % of impurities to a temperature of between about 1° and 5° below the freezing point of said crude liquid to form a vinyl pyrrolidone crystalline phase and a liquid residue phase in a first crystallization step; (b) separating said liquid phase from said crystalline phase; (c) allowing said separated crystalline phase to warm gradually so as to liquify said crystals and (d) subjecting the liquified crystals of vinyl pyrrolidone to between 1 and 3 additional crystallization steps, each carried out by gradually cooling the liquified vinyl pyrrolidone to a temperature above that of the preceding crystallization step up to a temperature of 14.4 °C so as to form additional vinyl pyrrolidone crystalline and liquid residue phases with separation of vinyl pyrrolidone crystals and liquid residue phases and liquification of vinyl pyrrolidone crystals between each additional recrystallization step, recovery of N-vinyl-pyrrolidone product from the final crystallization step and (II) collecting said separated liquid residues from each crystallization step and subjecting them, sequentially, individually or collectively, to fractional crystallization in order to recover additional amounts of purified vinyl pyrrolidone product. The present process is capable of achieving up to 99.999 % purity of vinyl pyrrolidone in about 98 % recovery.
摘要:
A process for the production of PVP-H2O2 products in the form of free-flowing powders, or a free-standing, porous solid or foam, is described. To prepare free-flowing powders, a fluidized bed is maintained at a reaction temperature of about room temperature to 60 °C and is contacted with finely divided droplets of a 30 to 85 % by weigth aqueous H2O2 solution. Preferably the fluidized bed temperature is about 35°-45 °C, a 5-70 % H2O2 solution is used, and the feed rate of introduction of the H2O2 solution is about 5-50 g/minute/kg PVP present. The PVP-H2O2 product preferably contains about 15-24 %, preferably 18-22 %, H2O2 (1:1 molar ratio) and less than about 5 % water.
摘要:
This invention relates to a process for the purification of a crude liquid N-vinylpyrrolidone product which comprises (I) product rectification by (a) subjecting said crude product containing at least 0.3 weight % of impurities to a temperature of between about 1° and 5° below the freezing point of said crude liquid to form a vinyl pyrrolidone crystalline phase and a liquid residue phase in a first crystallization step; (b) separating said liquid phase from said crystalline phase; (c) allowing said separated crystalline phase to warm gradually so as to liquify said crystals and (d) subjecting the liquified crystals of vinyl pyrrolidone to between 1 and 3 additional crystallization steps, each carried out by gradually cooling the liquified vinyl pyrrolidone to a temperature above that of the preceding crystallization step up to a temperature of 14.4 °C so as to form additional vinyl pyrrolidone crystalline and liquid residue phases with separation of vinyl pyrrolidone crystals and liquid residue phases and liquification of vinyl pyrrolidone crystals between each additional recrystallization step, recovery of N-vinyl-pyrrolidone product from the final crystallization step and (II) collecting said separated liquid residues from each crystallization step and subjecting them, sequentially, individually or collectively, to fractional crystallization in order to recover additional amounts of purified vinyl pyrrolidone product. The present process is capable of achieving up to 99.999 % purity of vinyl pyrrolidone in about 98 % recovery.