Abstract: An improved process for the polymerization of olefin monomer selected from (a) ethylene, (b) propylene, (c) mixtures of ethylene and propylene and (d) mixtures of (a), (b) or (c) with one or more alpha-olefins in a fluidized bed gas phase reactor, said process comprising passing a gaseous mixture of said olefin monomers(s) through the fluidized bed under effective polymerization conditions to provide a polymer product containing unreacted monomer(s) and a gaseous effluent stream comprising unreacted monomer(s), removing the polymer product to a degassing vessel, recycling a first portion of the gaseous effluent stream to the fluidized bed and passing a second portion of the gaseous effluent stream to counter currently contact the polymer product in said degassing vessel to produce a polymer product having a reduced amount of unreacted monomer(s), characterized in that the improvements to the process comprise: (i) removing heavy hydrocarbons from the second portion of the effluent stream and returning said hyd

Abstract: A process and apparatus for separating polymer solids, hydrocarbon fluids, and purge gas in an intermediate pressure zone and a purge zone. The purge gas in the purge zone is used to remove hydrocarbon fluids from the polymer solids, and a stream containing the purge gas and hydrocarbons is passed to a hydrocarbon/purge gas recovery zone. High-purity purge gas from the recovery zone is efficiently used by passing a portion back to the purge zone and another portion to an extruder feed zone. Hydrocarbon fluids separated from polymer solids in the intermediate pressure zone and in the hydrocarbon/purge gas recovery zone are liquefied and passed to a recycle zone, and the hydrocarbons (typically liquid diluent and/or unreacted monomer) are recycled to the reactor without fractionation.

Abstract: A process for the polymerisation of olefins is disclosed wherein at least part of a stream, preferably a catalytically active stream, withdrawn from a polymerisation reactor is passed through a fractionator so as to remove hydrogen and active fines.

Abstract: A continuous process for the olefin polymerization in a fluidized bed reactor, said process comprising continuously passing a gaseous stream comprising one or more ?-olefin monomers through the fluidized bed in the presence of a polymerization catalyst under reactive conditions, withdrawing polymeric product and unreacted fluids from the reactor, cooling part of said unreacted fluids below the dew point to form a two-phase mixture of gas and condensed liquid and reintroducing said two-phase mixture into the reactor, the process being characterized in that said two-phase mixture is reintroduced under the distribution plate of the reactor so that a part of condensed liquid is separated from the gas and is successively fed above the fluidized bed through an external pipe connecting the bottom of the reactor to a point situated above the upper limit of the fluidized bed of polymer particles.

Abstract: Method of producing vinyllactam copolymers by free-radical polymerization of at least one water-soluble N-vinyllactam and at least one hydrophobic comonomer in an organic solvent in the presence of an initiator under reflux conditions, where the condensate formed in the reflux is returned to the polymerization mixture from below.

Abstract: A process for the polymerisation of ethylene and optionally at least one C3-20 alpha olefin comonomer in the slurry or solution phase in a reactor having a polymer outlet stream, a procatalyst or catalyst feed stream and a hydrogen feed stream, said polymerisation being effected in the presence of a metallocene catalyst, a diluent and hydrogen, wherein said diluent is recycled from said outlet stream to said hydrogen feed stream, said procatalyst or catalyst feed stream is free of hydrogen, said hydrogen feed stream is free of procatalyst or catalyst and said procatalyst or catalyst feed stream does not comprise recycled diluent.

Abstract: Method of producing vinyllactam copolymers by free-radical polymerization of at least one water-soluble N-vinyllactam and at least one hydrophobic comonomer in an organic solvent in the presence of an initiator under reflux conditions, where N-vinyllactam is added to the reflux.

Abstract: The disclosure provides for a process and polymerization system to produce isoolefin polymers (72) utilizing polymorphogenates (16, 26) in the catalyst system to control polydispersity (MWD). The disclosure also provides a catalyst system (20) comprising a plurality of active catalyst complex species (34) formed by combination of a Lewis acid (24), an initiator (22) and a polymorphogenate (26), as well as polymers made using the catalyst system or process. The polymorphogenate (16, 26) can promote or mimic the formation of different active catalyst complex species (34) having different polymerization rates, i.e. different rates of propagation, chain transfer, or termination, as observed by different polydispersities resulting from the presence of relatively different proportions of the polymorphogenate.

Abstract: Methods of controlling the flow index and/or molecular weight split of a polymer composition are disclosed. The method of producing a polymer composition in one embodiment comprises incorporating a high molecular weight polymer into a low molecular weight polymer to form the polymer composition in a single polymerization reactor in the presence of polymerizable monomers, a bimetallic catalyst composition and at least one control agent; wherein the control agent is added in an amount sufficient to control the level of incorporation of the high molecular weight polymer, the level of low molecular weight polymer, or both. Examples of control agents include alcohols, ethers, amines and oxygen.

Abstract: A process for producing propylene homopolymers comprises producing a homopolymer in a reactor train having a first stage and a second stage, wherein the first stage is normally used for homopolymer production and the second stage is normally used only in the production of copolymer blends, and is left idle during homopolymer production. According to the invention, during the production of propylene homopolymer, the polymerization is carried out sequentially in both the first stage and second stage reactors.

Abstract: This invention relates to processes and plants for continuous solution polymerization. Such plan and process include a pressure source, a polymerization reactor, downstream of said pressure source, pressure let-down device, downstream of said polymerization reactor, and a separator, downstream of said pressure let-down device, wherein said pressure source is sufficient to provide pressure to said reaction mixture during operation of said process plant to produce a single-phase liquid reaction mixture in said reactor and a two-phase liquid-liquid reaction mixture in said separator in the absence of an additional pressure source between said reactor and said separator.

Abstract: Disclosed is a process for the removal and recycle of a supported transition metal catalyst complex from a polymerization reaction medium comprising the steps separating the supported transition metal catalyst from the reaction medium and contacting the supported transition metal catalyst with a reducing agent. The reducing agent may be a transition metal and/or a source of radicals. Also disclosed is a process for the recovery of transition metal catalyst from a reaction medium, comprising changing the conditions of a medium comprising transition metal catalyst attached to a solid support, wherein changing the conditions causes desorption of the transition metal catalyst from solid support.

Abstract: A polymerization process is provided. For example, a polymerization process is described, including contacting olefin monomers with a supported metallocene catalyst to polymerize the olefin monomers and form a product mixture that includes polyolefins macromers or polymers, unreacted or partially reacted olefin monomers, alcohols and organohalides. The polymerization process further includes removing a portion of the product mixture to form a recycle stream and passing the recycle stream through a removal device comprising zeolite particles having pore size of from 6 to 16 ? to transfer at least a portion of the alcohols and organohalides from the recycle stream to the removal device providing a purified recycle stream having alcohols and organohalides in an amount of 1 ppm or less. The polymerization process may further include contacting at least a portion of the purified recycle stream with the supported metallocene catalyst to form polyolefins.

Abstract: A recycling and recovery system and process comprising a flash gas separator that receives a slurry comprising liquid medium and solid polymer particles. The flash gas separator separates the diluent from the solid polymer particles as a vapor stream comprising at least diluent and heavies. A line receives the vapor stream from the flash gas separator. The line leads to a heavies removal system that yields a liquid that is relatively concentrated in heavies and a diluent vapor that is relatively free of heavies. The liquid is passed to a heavies column while the diluent vapor is passed to a diluent recycle chamber and then recycled to a slurry polymerization reactor without additional treatment to remove heavies.

Abstract: A process/apparatus is disclosed for continuously separating a liquid medium comprising diluent and unreacted monomers from a polymerization effluent comprising diluent, unreacted monomers and polymer solids, comprising a continuous discharge of the polymerization effluent from a slurry reactor through a discharge valve and transfer conduit into a first intermediate pressure flash tank with a conical bottom defined by substantially straight sides inclined at an angle to that of horizontal equal to or greater than the angle of slide of the slurry/polymer solids and an exit seal chamber of such diameter (d) and length (l) as to maintain a desired volume of concentrated polymer solids/slurry in the exit seal chamber such as to form a pressure seal while continuously discharging a plug flow of concentrated polymer solids/slurry bottom product of said first flash tank from the exit seal chamber through a seal chamber exit reducer with inclined sides defined by substantially straight sides inclined at an angle to t

Abstract: A continuous process for the process for the enzyme-catalyzed preparation of cyclic ester oligomers from linear ester oligomers. The process may use a linear or recirculating reactor.

Abstract: Enzymes which are capable of catalyzing esterifications and/or transesterifications such as selected lipases and esterases can, under specified conditions, convert certain lower linear oligomers of polyesters to their cyclic ester oligomers in quantities greater than would be predicted by thermodynamic calculation or prior art methods. The cyclic ester oligomers are useful for the production of higher molecular weight linear polyesters.

Abstract: The present invention provides an energy curable composition including a compound having an aromatic or heteroaromatic moiety; at least two fluorinated alkylene, arylene or polyether moieties, each fluorinated alkylene, arylene or polyether moiety being linked to the aromatic or heteroaromatic moiety through an —O— or —S— linkage; and at least one ethylenically unsaturated moiety, each ethylenically unsaturated moiety being linked to one of the fluorinated alkylene, arylene or polyether moieties. The present invention also provides an energy curable composition including a compound having an isocyanurate moiety, three fluorinated alkylene, arylene, or polyether moieties linked to the isocyanurate moiety at the nitrogens of the isocyanurate, and at least one ethylenically unsaturated moiety linked to one of the fluorinated alkylene, arylene, or polyether moieties. The present invention further provides polymeric materials and optical devices made using these compositions.

Abstract: Continuous gas-phase polymerization process for preparing ethylene and propene homopolymers and copolymers, in which ethylene, propene or mixtures comprising ethylene or propene and C3-C8-?-monoolefins are polymerized in the polymerization zone of a gas-phase polymerization reactor at from 30 to 125° C. and pressures of from 1 to 100 bar in the gas phase in a bed comprising finely divided polymer in the presence of a catalyst. To remove the heat of polymerization, the reactor gas is circulated and firstly passes through a cyclone after leaving the reactor. To prevent polymer deposits in the circulating gas system, a catalyst poison having a boiling point above the maximum temperature within the circulating gas system is fed into this circulating gas system at a position between the reactor and the cyclone.

Abstract: The invention relates to processes and plants for continuous solution polymerization. Such plant and processes include a pressure source, a polymerization reactor, downstream of said pressure source, pressure let-down device, downstream of said polymerization reactor, and a separator, downstream of said pressure let-down device, wherein said pressure source is sufficient to provide pressure to said reaction mixture during operation of said process plant to produce a single-phase liquid reaction mixture in said reactor and a two-phase liquid-liquid reaction mixture in said separator in the absence of an additional pressure source between said reactor and said separator.

Abstract: The present invention provides such a production process that a low-cost water-absorbent resin having excellent quality can be obtained by reasonable steps in aqueous solution polymerization. The production process for a water-absorbent resin comprises a polymerization setup that includes the steps of: supplying an aqueous solution of a water-soluble unsaturated monomer component including a major proportion of acrylic acid and/or its salt into a polymerization vessel causing shearing action; and then carrying out polymerization, involving crosslinking, of the water-soluble unsaturated monomer and at the same time carrying out fine division of the resultant hydrogel; with the production process being characterized in that the aqueous solution of the water-soluble unsaturated monomer component as supplied into the polymerization vessel has a temperature of not lower than 40° C.

Abstract: A flow reactor for liquid-phase polymerization reaction, which enables controlling the degree of polymerization for, for example, amino acid polymerization, wherein the liquid reaction mixture containing the organic reactive molecules to be polymerized is emitted from a high-temperature high-pressure part (A) to a low-temperature high-pressure part (B) via a circulation line (C), whereby inhibiting the decomposition of the polymer product in the low-temperature high-pressure part (B), after which the polymer product is once again sent to the high-temperature high-pressure part (A) through the circulation line for further polymerization, and the same cycle is repeated.

Abstract: Methods of controlling rheological properties of polymer compositions comprising at least one high molecular weight polymer and one low molecular weight polymer are disclosed. The polymer compositions are produced by polymerizing monomers in a single reactor using a bimetallic catalyst composition. A control agent such as, for example, an alcohol, ether, oxygen or amine is added to the reactor to control the rheological properties of the reactor. The polymerization takes place in the presence of rheological-altering compounds such as alkanes and aluminum alkyls. The control agents are added in an amount sufficient to counter the influences of the rheological-altering compounds.

Abstract: A recycling and recovery system and process comprising a flash gas separator that receives a slurry comprising liquid medium and solid polymer particles. The flash gas separator separates the diluent from the solid polymer particles as a vapor stream comprising at least diluent and heavies. A line receives the vapor stream from the flash gas separator. The line leads to a heavies removal system that yields a liquid that is relatively concentrated in heavies and a diluent vapor that is relatively free of heavies. The liquid is passed to a heavies column, while the diluent vapor is passed to a diluent recycle chamber and then recycled to a slurry polymerization reactor without additional treatment to remove heavies.

Abstract: The process for polymerizing olefins uses a plurality of series-connected polymerization reactors in which at least one of second and subsequent reactors is a vapor-phase polymerization reactor containing a multicomponent gas. The process comprises the steps of: taking the multicomponent gas out of the vapor-phase polymerization reactor; mixing the multicomponent gas with an inert gas which is lighter than at least one component of the multicomponent gas, thereby obtaining a mixed gas; compressing and/or cooling the mixed gas to liquefy a part of the multicomponent gas; discharging at least a part of a gaseous mixture comprising the inert gas and an unliquefied multicomponent gas out of a reaction system; and returning a fluid comprising the remainder of the gaseous mixture and the liquefied multicomponent gas to the vapor-phase polymerization reactor.

Abstract: The partially condensed fluid recycle stream of a fluidized bed polyolefin reactor operating in the condensing mode is split into two portions by a stream splitter. In a preferred mode, the smaller stream from the splitter contains a higher ratio of liquid to gas than the larger stream. One portion of the split stream is injected below the fluidized bed and the other, preferably with enhanced liquid content, is injected into the fluidized bed at a level above the product withdrawal level. Regulation of liquid injection above the product withdrawal level, as a function of liquid in the product discharge tanks, reduces the liquid in the product discharge system, resulting in improved discharge cycle times and more efficient conservation of monomer and other materials which might otherwise be lost in the discharge process.

Abstract: A method for carrying out homogenous polymerization reactions in a reactor, wherein monomers and/or prepolymers are fed (apportioned). In a first step, an initiator is optionally admixed with the monomer and/or prepolymer. In a second step, once viscosity is substantially higher, a solvent is added thereto and/or the monomer itself is partially evaporated, it is condensed externally and/or internally and fed back into the reactor.

Abstract: A process and apparatus for separating polymer solids, hydrocarbon fluids, and purge gas in an intermediate pressure zone and a purge zone. The purge gas in the purge zone is used to remove hydrocarbon fluids from the polymer solids, and a stream containing the purge gas and hydrocarbons is passed to a hydrocarbon/purge gas recovery zone. High-purity purge gas from the recovery zone is efficiently used by passing a portion back to the purge zone and another portion to an extruder feed zone. Hydrocarbon fluids separated from polymer solids in the intermediate pressure zone and in the hydrocarbon/purge gas recovery zone are liquefied and passed to a recycle zone, and the hydrocarbons (typically liquid diluent and/or unreacted monomer) are recycled to the reactor without fractionation.

Abstract: A recycling and recovery system and process comprising a flash gas separator that receives a slurry comprising liquid medium and solid polymer particles. The flash gas separator separates the diluent from the solid polymer particles as a vapor stream comprising at least diluent and heavies. A line receives the vapor stream from the flash gas separator. The line leads to a heavies removal system that yields a liquid that is relatively concentrated in heavies and a diluent vapor that is relatively free of heavies. The liquid is passed to a heavies column, while the diluent vapor is passed to a diluent recycle chamber and then recycled to a slurry polymerization reactor without additional treatment to remove heavies.

Abstract: A polymerization process and a catalyst delivery system are provided. For example, a polymerization process is described, including providing a conduit having a catalyst inlet, a first propylene stream inlet located downstream of the catalyst inlet, and a second propylene stream inlet located downstream of the first propylene stream inlet, the conduit being operably connected to a polymerization vessel, introducing a catalyst to the conduit through the catalyst inlet, and passing the catalyst through the conduit to the polymerization vessel. The process may further include introducing a first propylene stream to the conduit to provide a mixed catalyst stream downstream of the catalyst inlet. The process may additionally include stopping the flow of the catalyst passing through the conduit, introducing a second propylene stream to the conduit through the second propylene stream inlet, removing a section of the conduit, and replacing the removed section of the conduit with a different conduit section.

Abstract: A polymerization process is provided. For example, a polymerization process is described, including contacting olefin monomers with a supported metallocene catalyst to polymerize the olefin monomers and form a product mixture that includes polyolefins macromers or polymers, unreacted or partially reacted olefin monomers, alcohols and organohalides. The polymerization process further includes removing a portion of the product mixture to form a recycle stream and passing the recycle stream through a removal device comprising zeolite particles having pore size of from 6 to 16 Å to transfer at least a portion of the alcohols and organohalides from the recycle stream to the removal device providing a purified recycle stream having alcohols and organohalides in an amount of 1 ppm or less. The polymerization process may further include contacting at least a portion of the purified recycle stream with the supported metallocene catalyst to form polyolefins.

Abstract: The present invention relates to a catalyst composition of an activator, a catalyst compound and a support in a liquid. The catalyst composition of the invention is utilized as prepared, in the liquid, in a process for polymerizing olefin(s), preferably a slurry polymerization process.

Abstract: The use of two or more light solvent boiling pool reactors in series allows polymerization of ethylene and comonomer(s) to cost effectively produce bimodal polyethylene copolymers having lower densities than are practically achievable with conventional stirred tank, slurry loop or gas phase reactor technologies. Introducing catalyst to only the first reactor, operating the first reactor at high hydrogen compositions, and using a plurality of series-connected flash drums to remove hydrogen from the first reactor polymer slurry product stream allows for the production of highly homogeneous high molecular weight bimodal polyethylene resins.

Abstract: A process/apparatus is disclosed for continuously separating a liquid medium comprising diluent and unreacted monomers from a polymerization effluent comprising diluent, unreacted monomers and polymer solids, comprising a continuous discharge of the polymerization effluent from a slurry reactor through a discharge valve and transfer conduit into a first intermediate pressure flash tank with a conical bottom defined by substantially straight sides inclined at an angle to that of horizontal equal to or greater than the angle of slide of the slurry/polymer solids and an exit seal chamber of such diameter (d) and length (l) as to maintain a desired volume of concentrated polymer solids/slurry in the exit seal chamber such as to form a pressure seal while continuously discharging a plug flow of concentrated polymer solids/slurry bottom product of said first flash tank from the exit seal chamber through a seal chamber exit reducer with inclined sides defined by substantially straight sides inclined at an angle to t

Abstract: A gas-phase process for polymerizing an olefin is disclosed. The process involves feeding the catalyst into the reactor in a stream of gas that comprises at least 75 volume % of a noble gas in order to reduce static.

Abstract: Preactivated unsupported catalyst compositions methods of using them are disclosed whereby the compositions have a concentration of preactivated catalyst of at least about 0.04 mmol of preactivated catalyst per liter of solution when using aliphatic or alicyclic hydrocarbon solvents, and a concentration of less than about 0.80 mmol/liter when using aromatic or halogen-substituted solvents. In the method, an unsupported catalyst precursor first is contacted with an activator, or co-catalyst, in a suitable reaction medium, and then the resulting mixture is contacted with additional solvent to form a preactivated unsupported olefin polymerization catalyst composition that can be fed to a gas phase polymerization reactor without plugging the catalyst injection nozzle.

Abstract: A process for the continuous gas-phase (co)polymerization of one or more olefins for which a rising stream of a gas mixture, comprising at least one olefin to be (co)polymerized, maintains polymer particles in the course of formation in the fluidized state in a polymerization reactor, the said stream entraining fine particles above the fluidized bed outside the reactor, the said fine particles being substantially separated from the gas mixture using a separator, thus dividing the said stream into (i) one or more gas streams (A) substantially devoid of solid particles which is cooled and reintroduced below and/or into the bottom part of the fluidized bed, and (ii) one or more gas streams (B) comprising at least a portion of the said particles which is introduced into or above the fluidized bed, which process is characterized in that at least one of the gas streams (B) comprising the solid particles is introduced directly into the fluidized bed by a dilute-phase transport in a simple pipe, that is to say prefer

Abstract: A process for polymerizing monomers in the gas phase, in fluidized bed reactors is described, where unsaturated, gas phase monomers are fed into the reactors in the presence of a mixture of inert diluents having a composition that allows the dew point to be adjusted, this leading to high production rates under stable operation in a non condensed operation mode.

Abstract: Continuous process for manufacturing a polyolefin resin in at least two polymerization reactors connected in series, in which the polymer suspensions leaving the reactors are transferred into hydrocyclone separators in which a flow comprising diluent and polymer particles, on the one hand, and a concentrated suspension of polymer particles, on the other hand, are formed and separated. The flows comprising the polymer particles are recycled into the first polymerization reactor.

Abstract: Process for manufacturing an olefin polymer composition in at least two polymerization reactors connected in series, in which the suspension of polymer in a diluant, formed in the first reactor, is sent into a hydrocyclone seperator in which, on the one hand, a stream comprising diluant and, on the other hand, a concentrated suspension of polymer particles are formed and separated. The concentrated suspension is then introduced into the subsequent polymerization reactor.

Abstract: A process for preparing polyvinyl alcohol by means of catalytic transesterification of an alcoholic polyvinyl ester solution and subsequent workup by means of isolation of the polyvinyl alcohol formed includes adding, prior to the transesterification of the polyvinyl ester solution, the acetic ester of the alcohol used as solvent, in an amount of from 5 to 70% by weight, based on the overall amount of alcoholic solvent and its acetic ester, and recycling the liquid phase obtained after isolation of the polyvinyl alcohol product to a further polyvinyl ester transesterification.

Abstract: There is disclosed a process for producing an ethylenic oligomer which comprises subjecting ethylene to oligomerization reaction in an organic solvent in the presence of a Ziegler based catalyst, and recyclingly using for the oligomerization reaction, the organic solvent separated by distilling the resultant oligomerization reaction product, wherein the water concentration in the oligomerization reaction system is at most 8 ppm by weight, or the concentration of olefins which have at least 3 carbon atoms and which are contained in the organic solvent to be recycled in the oligomerization reaction system is at most 2% by weight. The process of the present invention can maintain the catalytic activity of the catalyst at a high level.

Abstract: An apparatus and method for continuously removing polymer from a pressurized loop olefin polymerization reactor containing a slurry of polymer particles and fluids. The slurry is continuously discharged from polymer-rich zones of the reactor and enters one or a series of non-cyclonic flash vessels, in which the particles separate from the fluid. The flash vessel has a conical bottom in which a minimum level of polymer is maintained for a dynamic seal between the inlet and outlet.

Abstract: A process and apparatus for passing a polymerization effluent, comprising solid polymer, unreacted monomer, diluent and minor amounts of contaminants, to a high pressure flash where most of the fluid components are flashed and wherein a slip stream comprising diluent and minor amounts of monomer is separated from the bulk of the flashed fluid components. The slip stream is subjected to olefin removal to give an essentially olefin-free stream for recycle to a catalyst mud preparation area. The bulk of the flashed fluid components are recycled directly back to the polymerization zone without expensive olefin removal, although treatment to remove other contaminants can optionally be performed. The polymer and entrained fluid is passed to a low pressure flash zone where the fluids are flashed off, compressed and joined with the flash from the high pressure flash tank.

Abstract: A method for continuously separating polymer from a high pressure fluid stream comprises subjecting the high pressure fluid stream comprising polymer particles to a filter, wherein the filter segregates the high pressure fluid stream from the polymer particles; subjecting the polymer particles to a rotating device which transports the polymer particles away from the filter, wherein the polymer particles are exposed to thermal conditions sufficient to melt the polymer particles and form a seal surrounding at least a portion of the rotating device; and separating the molten polymer from the rotating device. The method is carried out such that the separation of polymer from the high pressure fluid stream occurs under steady-state.

Abstract: A process for producing polyamides by reacting at least one lactam and optionally further polyamide-forming monomers with aqueous monomer and oligomer extracts obtained during the extraction with water of the polymer product obtained in the production of polyamides, the water content of the reaction mixture being in the range from 0.5 to 13% by weight comprises conducting the reaction in the presence of metal oxides, beta-zeolites, sheet-silicates or silica gels, which may be doped, as heterogeneous catalysts, the heterogeneous catalysts being used in the form which permits mechanical removal from the reaction mixture and are removed from the reaction mixture in the course of the polymerization or after it has ended.

Abstract: The space time yield of a gas phase reactor, particularly a polyethylene reactor may be increased by replacing at least 80 weight % of the ballast gas with a gas having a higher heat capacity than the ballast gas. Preferably the gas replacing the ballast gas is a stream of dilute ethylene having a high concentration of ethane.

Abstract: The invention relates to a process for the production of polyamide-6 by polymerization of &egr;-caprolactam with full re-use of extracted caprolactam and oligomers. The extract is not subjected to a pretreatment for reduction of the cyclic dimer content. By carrying out the polymerization in two steps, the first at an elevated pressure, but lower than the vapor pressure of the reaction mixture supplied, and the second at approximately atmospheric or reduced pressure, the cyclic dimer content of the polymerizate leaving the second polymerization step is kept at a constant level. The process offers a high degree of flexibility in terms of production capacity and composition and proportion of recycled lactam in the lactam feed for the polymerization.

Abstract: The present invention provides: a production process that enables to keep foaming state within a constant level and to obtain a polymer with good productivity and reproducibility with a practical plant by defining an appropriate vapor velocity from a weight-average molecular weight of the polymer that is finally intended to obtain; and a polymerization apparatus therefor. A production apparatus for producing a polymer, which comprises a reactor 1 in order to produce the polymer, a stirrer 2 in order to stir a reaction solution in the reactor 1, and a condenser 3 so that a vaporized reaction solution can be cooled and returned to the reactor 1, and further comprises a vapor velocity measuring means of monitoring a vapor velocity in the condenser, and an vapor velocity adjusting means of adjusting the vapor velocity, is used. Then, the vapor velocity is adjusted in the range of 0.001 to 0.

Abstract: Polyisobutenes are prepared by the continuous preparation process, by polymerizing isobutene in the presence of a catalyst comprising boron trifluoride and at least one cocatalyst in an inert organic solvent, a) a part of the reaction mixture obtained thereby being discharged continuously from the polymerization reactor, b) the catalyst being separated from the discharge and/or being deactivated in the discharge, and c) the solvent and any unconverted isobutene being separated from the discharge and recycled to the polymerization reactor, wherein the recycled solvent and, if present, the isobutene are subjected to a wash with water before recycling to the polymerization reactor and are then dried.

Abstract: Disclosed is a method and apparatus for continuously forming and depositing a layer of monomolecular amphiphilic molecules on a substrate. The present invention includes an apparatus and method for transferring and compressing an uncompressed molecular layer from one liquid surface region in a tank to another adjacent liquid surface region by using non-moving or static mechanical components which do not come into direct contact with the monomolecular layer. The present invention includes a method and apparatus which permit the continuous and simultaneous draining and replenishing of the liquid in the tank while maintaining the liquid surface level constant. The continuous replacement of the liquid in the tank with clean liquid reduces the level of contamination of the liquid in the tank. In addition, the level, as well as the type of contamination of the liquid, does not vary significantly with time.