Abstract: A desired unreacted monomer concentration is maintained in the reaction effluent removed from a polymerization reactor by manipulating the catalyst feed rate to the polymerization reactor.

Abstract: A method for detecting the stoichiometric end point of a preparation of aromatic polycarbonate resin involving the use of phosgene and an organic solvent in which the phosgene is normally soluble which comprises detecting the increase of phosgene gas occurring in the vapor phase of the reactor at or following achievement of the stoichiometric end point of the aromatic polycarbonate preparation.

Abstract: The invention is to provide an improved process for preparing polyolefins having predetermined properties, in particular, melt index and/or density by polymerizing olefin in the presence of a Ziegler catalyst and hydrogen. The parameters corresponding to the concentrations of olefin and hydrogen, participating in the properties, in the gas phase of reactor are detected by high-speed gaschromatography. The detected signals are applied to a computer.The feed volumes of olefin and hydrogen into the reactor are controlled by means of an operation control output, and the respective concentrations in the reactor are controlled. Consequently, the resulting polyolefins possess extremely stable and uniform properties.

Abstract: A method for determining the concentration of ingredients and other process variables in a polymerization process by measuring the capacitance and dissipation factor of the mixture and determining its dielectric constant at various stages of the process. By the use of an automatic capacitance bridge and a computer, the process variables can be determined and controlled in a matter of seconds.

Abstract: A method for determining the concentration of additives in a compounding process by measuring the capacitance and dissipation factor (tan.delta.) of the mixture and converting such values to the concentrations of the additives. This method may also be utilized to determine the concentration of the polymers in the mixture. This method is preferably applied to a compounding process of blending polyphenylene oxide and polystyrene thermoplastic resins and is preferably applied to a continuous compounding process of these resins to determine therein the concentration of an aryl phosphate ester flame retardant.

Abstract: Polycarbonates are prepared in homogeneous solutions from dihydric phenols and phosgene wherein the stoichiometric end point for the addition of phosgene is accurately controlled by using 4-(p-nitrobenzyl) pyridine as a colorometric indicator for the end point in a series of samples of the reaction solution.

Abstract: A method for detecting solidification in a mixed phase low pressure fluidized bed olefin polymerization reactor having volume comprising:A. disposing a radiation source and a radiation detector such that radiation from said radiation source will pass through a radiation path through at least a portion of the volume of said container to reach said radiation detector,B. detecting solidification in said radiation path by noting a decrease in the amount of radiation reaching said radiation detector.

Abstract: In a continuous process for producing olefin polymers by contacting olefin monomers with an initiator or catalyst in a polymerization zone, the improvement comprising contacting fast poisons in the feed with a scavenging agent in a scavenging zone under conditions such that no significant amount of polymerization occurs until said feed is contacted with the initiator or catalyst in a polymerization zone.

Abstract: A process for the continuous high pressure polymerization of ethylene in a polymerization system which comprises a polymerization zone (A), a high pressure product isolation zone (B), a throttling and control system (C), a low pressure product isolation zone (D), a second throttling and control system (E) and a discharge extruder (F), and wherein, according to the invention, the level of the ethylene polymer in the high pressure product isolation zone (B) and in the low pressure product isolation zone (D) is varied periodically. The process gives an ethylene polymer of improved homogeneity, which when used to manufacture films does not tend to form specks or fisheyes.

Abstract: In a continuous process for the production of ethylene terephthalate polyesters, when the control value for the viscosity which relates to the degree of the polymerization in a polymerization vessel exceeds a predetermined value, a desired command value of the viscosity at the output of the preceding polymerization vessel is automatically revised.

Abstract: The invention is directed to a pycnometer designed to measure the density of particulate porous polymer samples, particularly polymer samples having hydrocarbons and/or air absorbed in the pores thereof. The apparatus includes a sample cell of fixed volume fitted with a sample container of fixed weight, a gas reservoir of fixed volume, a valved line providing gas communication between the sample cell and the gas reservoir, a linear variable differential transducer to measure the weight of the polymer sample in the sample cell, a variable capacitance quartz crystal for measuring gas pressure in the gas reservoir, and a computer which calculates the density of the sample from the sample weight, and the volume of the sample determined by measurement of a super-atmospheric gas pressure in the gas reservoir when isolated from the sample cell and the equalized pressure established when the gas reservoir is placed in open communication with the sample cell.

Abstract: In a process control system, a control signal to the process is provided to a process model having a predictive element and a delay element adapted to reproduce as closely as possible the action of the measured process variable to the control signal. The variable input signal to the process controller, upon which generation of the process control signal is based, is generated by multiplying the signal from the predictive portion of the process model by a correction factor generated in response to the ratio of the actual process measurement signal to the delayed model output signal.

Abstract: A control method wherein the control signal is generated from a disturbance signal, the functional relationship between these signals being an equation based on two dead times and a first order lag and a first order lead, the ratio of the time constants of this equation being equal to the fourth power of the ratio of the time constants of the disturbance dynamics and of the control dynamics of the process to be controlled.

Abstract: A fluid bed reactor system and process employing a silyl chromate catalyst therein wherein the reactor system comprises a vertical reactor having a fluidizing medium permeable distribution plate towards the base thereof, a fluidizing medium supply line to supply fluidizing medium to the base of the reactor, a catalyst injection means to supply particulate catalyst to the side of the reactor, a polymer product recovery means to recover polymer product from the reactor and beneath the distribution plate, a fluidizing medium recycle line to recycle the fluidizing medium from and to the reactor, and a heat exchanger in the recycle line to remove heat of reaction from the recycled fluidizing medium.

Abstract: Copolymers of acrylonitrile and conjugated aromatic olefines, such as styrene, containing 50-95% molar of acrylonitrile are made using an aqueous suspension process in which hydroxyethyl cellulose is used as the suspension agent.

Abstract: Copolymers of acrylonitrile and conjugated aromatic olefines, such as styrene, containing 50-95% molar of acrylonitrile are made using an aqueous suspension process in which polyvinyl pyrrolidone is used as suspension agent.

Abstract: Polymerization of a monomer, either alone or present in major proportion with one or more comonomers present in minor proportion, is accomplished by controlling the major monomer feed rate in response to a signal representative of the production rate of the polymerization process, unless the major monomer concentration within the reaction zone exceeds a preselected high limit causing the major monomer feed rate to be controlled in response to the concentration of the major monomer within the reaction zone. The flow of recycle diluent to the reaction zone is controlled in response to the concentration of major monomer within the reaction zone unless the solids concentration within the reaction zone exceeds a preselected high limit, in which case the flow of recycle diluent to the reaction zone is controlled in response to the concentration of solids within the reaction zone.

Abstract: A method of measuring the extent of an exothermic chemical reaction while the reaction is proceeding which comprises measuring the difference between the ingoing and outgoing temperatures of a coolant passing through the reaction vessel and computing therefrom the heat produced by the reaction, and in which the numerical value of the temperature of the ingoing coolant is retained in a memory device before being compared with that of the outgoing coolant, the period of retention being equal to the time taken for coolant to pass from the point of measurement of the ingoing temperature to the point of measurement of the outgoing temperature. This corrects errors due to variations with time of the temperature of the ingoing coolant.

Abstract: A method is provided for controlling polymer particle size in emulsion polymerization in which at least one emulsifier is added to a polymerization reaction mixture containing at least one ethylenically unsaturated monomer at a rate determined by the rate at which heat is evolved by free radical catalyzed polymerization of the monomer such that the total amount of emulsifier fed to the reaction mixture up to any one time is related to the total amount of heat evolved up to that time.