Abstract: The invention relates to a method and a device for producing polyesters such as for example polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate from precondensates. According to said method, vapors comprising precondensate components that are distributed therein in the form of an aerosol are guided through a polycondensation reactor in which precondensate components condense on the reactor wall and on a separator in an exit chamber of the reactor. The condensates are guided to the unstirred discharge sump and the upper layers of the discharge sump are continuously recirculated into the stirred reactor area thereby subjecting them to reconversion and additional polycondensation.

Abstract: An olefin polymerization reactor of the present invention includes a cylinder which extends vertically, and a decreasing diameter member which is formed on the cylinder, has an inside diameter that decreases progressively downward and has a gas inlet orifice at a bottom end thereof. A spouted bed is formed inside a reaction zone enclosed by an inside surface of the decreasing diameter member and an inside surface of the cylinder above the decreasing diameter member.

Abstract: Disclosed herein is a method of operating a polymerization reactor for a polymerization reaction comprising modifying a recycle gas composition to increase the heat capacity of the recycle gas wherein the recycle gas composition is modified by reducing or eliminating the nitrogen concentration in the recycle gas. In an embodiment, the nitrogen concentration is reduced or eliminated by reducing or eliminating one or more nitrogen input sources to the polymerization reactor and replacing the nitrogen with an alternate inert fluid (a gas or liquid that is inert to the catalyst and reactants). The alternate inert fluid has a higher heat capacity and a higher molecular weight than nitrogen. In an embodiment, the nitrogen utilized to convey a catalyst into the polymerization reactor is replaced with an alternate inert fluid. In an embodiment, the alternate inert fluid is ethane, propane, isobutane, or combinations thereof.

Abstract: The polymer degassing apparatus includes a barrel-shaped horizontal container 41 having a supply port 42 for supplying a reactant, a discharge port 43 for discharging a reactant, a stirring means 45 for stirring a reactant, and a degassing means for drawing a gas via a degassing port 44 of the horizontal container. The supply port is positioned below the molten liquid level of the reactant. A recovery container 37 that is connected to the degassing port for recovering a volatile substance in the gas and a vacuum pump 36 are provided. The stirring means includes a plurality of stirring rods 46 oriented along the same direction as the axis in the horizontal container and coupling members 47 for coupling the stirring rods along the same direction as the axis, provided that the coupling members are placed at a distance from the virtual rotation center of the stirring means.

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: The present invention relates to a continuous gas phase process comprising polymerizing one or more hydrocarbon monomer(s) in a fluidized bed reactor in the presence of a Ziegler-Natta-type catalyst system and a condensable fluid for a period of at least 12 hours where the bed temperature is less than the Critical Temperature and the dew point temperature of the gas composition in the reactor is within 25° C. of the bed temperature.

Abstract: Methods for treating a gas mixture of at least propylene and propane, in order to separate the propylene from the propane. The gas mixture is brought into contact with a membrane enables the selective permeation of the propylene with respect to the propane. A propylene-enriched permeate and a propane-enriched retentate is formed. The propylene concentration of the permeate in the membrane is then reduced with a sweeping gas.

Abstract: The present invention relates to a process for controlling the gas-phase co-polymerisation of olefins in a fluidised bed reactor. The present invention further relates to a method for the continuous gas-phase (co-)polymerisation of olefins in a fluidised bed reactor in the presence of a polymerisation catalyst wherein the density SPAN of the polymer powder particles leaving the reactor is maintained below certain values throughout the polymerisation.

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: Processes for reducing the ultra high molecular weight polymeric material content of a high density polyethylene produced with a bis-triarylsilyl chromate catalyst system are provided. Processes for reducing the gel content of articles produced from high density polyethylene are also provided. The gel content of the articles is reduced by using the high density polyethylene with reduced ultra high molecular weight polymeric material content to produce the articles. The processes described reduce the content of ultra high molecular weight polymeric material in comparison to conventional high density polyethylene by introducing at least one catalyst deactivator into a recycle gas line containing a recycle gas stream associated with the fluidized bed reactor. The at least one catalyst deactivator has a boiling point lower than the maximum temperature within the recycle gas line.

Abstract: The present invention relates to a gas phase process for polymerizing one or more hydrocarbon monomer(s) in the presence of a catalyst system and a fluorinated hydrocarbon, where the fluorinated hydrocarbon is present at a partial pressure of 6.9 to 348 kPa in the reactor and the reactor temperature is from 30 to 120° C.

Abstract: The invention relates to a process for the polymerisation of monomeric vinyl halides in a polymerisation reactor, especially using a flow-through cooler, and also to a polymerisation reactor for carrying out the process according to the invention. As a result, the space-time yield (STY) of an exothermal reaction can be substantially improved whilst the product quality remains almost the same.

Abstract: A monomer recycle process for fluid phase in-line blending of polymers is provided.

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 carbonylation of a conjugated diene to an ethylenically unsaturated acid, comprising the steps of (a) contacting a conjugated diene with carbon monoxide and water in the presence of a catalyst system including a source of palladium, a source of an anion and a bidentate phosphine ligand, to obtain a mixture comprising an ethylenically unsaturated acid and a reversible diene adduct comprising alkenyl ester of the conjugated diene with the ethylenically unsaturated acid; (b) separating the obtained reaction mixture into a gaseous stream comprising unreacted conjugated diene and carbon monoxide, a first liquid product stream comprising at least part of the ethylenically unsaturated acid and the reversible diene adducts, and a second liquid stream comprising the catalyst system in admixture with the ethylenically unsaturated acid; (c) separating the first liquid product stream obtained in step (b) into a stream comprising the ethylenically unsaturated acid and a stream comprising the reversible d

Abstract: In a process for the preparation of copolymers containing vinyl esters and ethylene or ethylenically unsaturated monomers by aqueous, free radical polymerization at a pressure of from 5 to 100 bar absolute by the emulsion or suspension polymerization method, after the end of the polymerization, the reaction mixture is let down to a pressure of from 0.1 to 5 bar absolute and recovery of unconverted monomers is effected by multistage fractional low-temperature condensation from the residual gas.

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: A process for transporting a liquid monomer phase which has been withdrawn from a storage vessel and comprises methacrylic monomers to an extent of ?90% by weight, in a tank truck or in a tanker ship, in which the liquid monomer phase is subjected to a separating operation on the route from the storage vessel into the tank of a tank truck or of a tanker ship in order to separate polymer of the monomer present in dissolved form in the liquid monomer phase.

Abstract: Process for removing unconverted residual monomers from polyoxymethylenes, wherein a devolatilization step is carried out in an extrudate devolatilizer.

Abstract: The present invention relates to the use of an additive for improving the flowability of fines and their reintroduction into a process for the continuous gas-phase (co-) polymerisation of olefins in a fluidized bed or sub-fluidized bed reactor.

Abstract: Process for the polymerization of ethylene or of ethylene with further 1-olefins, in which the ethylene is polymerized in the presence of a catalyst in a gas-phase reactor and reaction gas comprising propane and unpolymerized ethylene is circulated to remove the heat of polymerization, wherein the polymer particles are discharged continuously or discontinuously from the reactor, the polymer particles are separated from the major part of the concomitantly discharged gas and the polymer particles are degassed, the gas is freed of entrained fine particles and is separated from a low-boiling fraction comprising ethylene or from a high boiling fraction containing further 1-olefins or alkanes having from 4 to 12 carbon atoms in a first separation stage, a propane fraction is separated off in a second separation stage and this propane fraction is used for degassing the polymer particles discharged from the reactor, with the proportion of ethylene in the propane fraction being less than 1 mol % and the proportion of

Abstract: This invention relates to a process for polymerizing olefins, comprising the steps of: (a) contacting in one or more reactors, in a dense fluid homogeneous polymerization system, olefin monomers having three or more carbon atoms present at 30 weight % or more (based upon the weight of the monomers and comonomers entering the reactor), with: 1) one or more catalyst compounds, 2) one or more activators, 3) from 0 to 50 mole % comonomer (based upon the amount of the monomers and comonomers entering the reactor), and 4) 0 to 40 wt % diluent or solvent (based upon the weight of the polymerization system), at a temperature above the crystallization temperature of the polymerization system and a pressure no lower than 10 MPa below the cloud point pressure of the polymerization system and less than 200 MPa, where the polymerization system comprises the monomers, any comonomer present, any diluent or solvent present, any scavenger present, and the polymer product; (b) forming a reactor effluent comprising a polymer-mo

Abstract: A method for producing an ethylene polymer which comprises continuously polymerizing ethylene alone or copolymerizing ethylene and a C3-C8 ?-olefin by multistage polymerization in a plurality of polymerization reactors connected in series in the presence of a chromium catalyst having at least a part of chromium atoms converted to hexavalent chromium carried on an inorganic oxide carrier by calcination-activating in a non-reducing atmosphere, wherein an organoaluminum compound of the formula (1): (R1)xAl(OR2)y(OSiR3R4R5)z??(1) (in the above formula, R1 and R2 may be the same or different, each represents a C1-C18 alkyl group or a C6-C18 aryl group, R3, R4 and R5 may be the same or different, each represents a C1-C18 alkyl group or a C6-C18 aryl group, R1, OR2 and OSiR3R4R5 respectively may be the same or different when each has a plurality of kinds, and x, y and z are respectively 0?x?3, 0?y<3, 0?z<3, and x+y+z=3) is introduced at least one or all of the polymerization reactors.

Abstract: Methods of producing vinyllactam copolymers which include: providing at least one water-soluble N-vinyllactam; providing at least one hydrophobic comonomer; and subjecting the at least one water-soluble N-vinyllactam and the at least one hydrophobic comonomer to free-radical polymerization in an organic solvent in the presence of an initiator, under a combination of process measures selected from the group consisting of A and B; wherein: (A) comprises (i) polymerization under reflux, and at least two of (ii), (iii), (iv), (v), (vi), and (vii), wherein (ii) comprises an addition of at least 5 mol % of N-vinyllactam to the polymerization mixture if at least 70 mol % of the total amount of hydrophobic monomer used have completely reacted, (iii) comprises return of condensate formed in the reflux from below to the polymerization mixture, (iv) comprises introduction of the initiator in the form of a solution in an organic solvent from below into the polymerization mixture, (v) comprises addition of N-vinyllactam t

Abstract: The present invention relates to a process for improving the start up of polymerization or copolymerization of ethylene in a gas phase reactor, preferably a fluidized bed gas phase reactor.

Abstract: The present invention relates to a continuous gas phase process comprising polymerizing one or more hydrocarbon monomer(s) in a fluidized bed reactor in the presence of catalyst system or polymerization catalyst and a condensable fluid for a period of at least 12 hours where the bed temperature is less than the Critical Temperature and the dew point temperature of the gas composition in the reactor is within 25° C. of the bed temperature.

Abstract: The present invention relates to a process for improving the start up of polymerization or copolymerization of ethylene in a gas phase reactor, preferably a fluidised bed gas phase reactor.

Abstract: Process for treating polyolefin discharged from an olefin polymerization reactor which comprises steps of discharging from a polymerisation reactor a slurry comprising polyolefin and diluent; submitting said slurry to a pressure release such that the diluent is evaporated and a polyolefin/gas mixture is formed; discharging said polyolefin/gas mixture into a collecting vessel; controlling a level of settled polyolefin in the collecting vessel; discontinuously transferring the polyolefin/gas mixture in the collecting vessel into a concentrating vessel; and discharging said concentrator vessel in such a way that said polyolefin/gas mixture is transferred into the hydrocarbon purge bin. Embodiments also comprise the use of two interconnected concentrator vessels and the optimized recovery of the diluent from the purge bin.

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: An improved process for recycling unspent diol removed from a polyester manufacturing process wherein the diol is captured, hydrogenated, and recycled so that the final polyester product has improved color over polyesters produced using other recycled diols.

Abstract: The present invention relates to a continuous gas phase process comprising polymerizing one or more hydrocarbon monomer(s) in a fluidized bed reactor in the presence of catalyst system or polymerization catalyst and a condensable fluid for a period of at least 12 hours where the bed temperature is less than the Critical Temperature and the dew point temperature of the gas composition in the reactor is within 25° C. of the bed temperature.

Abstract: The present invention provides a method of separating unreacted monomer from a polymerization process effluent stream. The polymerization process effluent stream has at least the following components: unreacted monomer, polymer, and solid fines. The method comprises passing the effluent stream through one or more filters disposed within a vessel at a pressure of from about 150 psig to about 400 psig and thereby obtaining a stream of vapor containing less than about 0.5 weight percent solid fines.

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 invention relates to a method for producing polycarbonate according to the method for the transesterification of molten mass whereby bis-(hydroxyaryl) compounds (bisphenols) and diaryl carbonates are reacted by means of reactive rectification.

Abstract: This invention concerns using an intermediate grade propylene stream as feed to a polypropylene forming reaction system. The intermediate grade propylene stream is preferably recovered form the olefin product of an oxygenate to olefins reaction process, and low in dimethyl ether content.

Abstract: A process to support a homogeneous catalyst on a porous solid support is performed in two separate zones. In the first zone the solid is contacted, under stirring, with an amount of a catalyst solution lower than the total pore volume of the solid. In the second zone the solid is dried from the solvent while flowing under pneumatic conveying. A loop circulation of solid is established between the two zones, so that the solid is subject to more contacting steps. The process is particularly suitable to support a metallocene-alumoxane polymerization catalyst on a porous prepolymer. The process can be advantageously performed in continuous, thus fitting the needs of an industrial scale production process.

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: 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: 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: A continuous process for converting by transesterification the diester of polytetramethylene ether (PTMEA) to the corresponding polytetramethylene ether glycol (PTMEG). The process is characterized by the fact that the feed, consisting of PTMEA along with an alkanol (preferably methanol) and with an alkali metal oxide, hydroxide or alkoxide catalyst (preferably sodium methaoxide) is made to react in two multistaged reactions in series. In the first reactant, including stages of retention in association with distillation trays of high efficiency, the bulk of conversion is achieved by stripping the alkanol ester formed in the transesterification with vapors of hot alkanol having a reduced content of alkanol ester. The transesterification is completed in the second reaction by stripping the effluent from the first reactor with vapors of hot alkanol almost free of alkanol ester.

Abstract: The present invention relates to a process for polymerizing monomer and comonomer(s) utilizing a bulky ligand transition metal metallocene-type catalyst or catalyst system, where the process is operated in the absence of or with a low amount of any of the isomers of the comonomer(s). The level of these isomers in the process of the invention are eliminated or maintained below a threshold level. It has been discovered that removal of certain isomers of the comonomer used in a polymerization process using metallocene-type catalysts results in an improved process.

Abstract: A polymerization process and polymerization reactor are provided. For example, a polymerization process is described, including passing a feed stream including liquid and gas through a feed stream inlet disposed proximate an upflow polymerization reactor, passing the feed stream through a member configured to impart an angular velocity to the feed stream and entrain the liquid in the gas, and contacting the feed stream with a catalyst to polymerize the feed stream.

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: A process for preparing polyethylene from “feed ethylene” comprises: a) a hydrogenation stage in which “feed ethylene” containing impurities or secondary components such as acetylene and ethane is reacted with hydrogen to remove the acetylene by catalytic hydrogenation to form ethylene and part of the ethylene is converted into ethane, and b) a polymerization stage in which the ethylene leaving stage a) is reacted in the gas phase in a fluidized-bed reactor to form polyethylene, where the fluidizing gas used comprises, on entering the reactor, ethene and from 20 to 70% by volume of ethane, based on the total volume of the fluidizing gas, possibly together with further components, where, in a), ethylene is converted in a targeted manner into ethane in addition to the ethane already present in the “feed ethylene” so that the concentration specified in b) results. An apparatus for carrying out the process is also provided.

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: Ethylenically unsaturated monomers are polymerized in a gas-phase fluidized-bed reactor comprising a reactor space (1) in the form of a vertical tube, a calming zone (2) adjoining the upper part of the reactor space, a circulated gas line (3), a circulated gas compressor (4), a cooling apparatus (5), a gas distributor plate (6) which forms the lower boundary of the reactor space and, if desired, a flow divider (7), wherein the gas distributor plate (6) has a plurality of gas flow orifices (8) whose outlet sides are widened conically.

Abstract: Tubular reactor apparatus and processes are provided for improved polymerization including using chain transfer agents and multiple monomer feeds spaced lengthwise along the tubular reactor providing high conversions of monomer into polymer. The invention also relates to polymers made from such a tubular reactor apparatus and processes including those polymers having a low haze value, a density over 0.92 g/cm3 and/or having terminal carbonyl groups. The apparatus and methods uncouple or reduce the dependency between the monomer concentration and transfer agent concentration. The uncoupling in other embodiments may also be varied leading to multiple desirable effects.