Abstract: Process technology is described making possible substantial improvements in the separation and recovery of highly pure vinyl aromatic monomers, notably styrene. A number of design, construction and operational features are made available for selection and use both for new plant facilities and for upgrading existing plant facilities. One major aspect of the invention is reduction in retention or residence times in the distillation towers. In another embodiment, a startup process comprises (i) introducing a feed comprising vinylaromatic monomer, polymerization inhibitor, aromatic hydrocarbon components having boiling points above that of the vinylaromatic monomer to a packed distillation column, said column having a maximum theoretical .DELTA.

Abstract: A method of inhibiting fouling of one or more pieces of equipment for processing crude epichlorohydrin by treating at least one epichlorohydrin stream entering or exiting the one or more pieces of equipment with hydroquinone as an antifoulant.

Abstract: A process for preparing refined acrylic esters, the process including steps of distilling an acrylic ester containing stream in the presence of hydroquinone or substituted hydroquinone, at a concentration in the range of 200 to 5000 ppmw, wherein the distillation is carried out in the presence of 0.001 to 1.0 % v, on the vapor phase, of oxygen.

Abstract: The polymerization of a vinylaromatic or vinylaliphatic compound at elevated temperature in the absence of air is inhibited by processing the vinylaromatic or vinylaliphatic compound in the presence of 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl or 4-acetylamino-2,2,6,6-tetramethylpiperidine-N-oxylalone or in admixture with p-nitrosophenol or 2-methyl-4-nitrosophenol.

Abstract: A method of inhibiting the formation of fouling deposits occurring in spent caustic wash systems used for ethylene dichloride (EDC) manufacturing processes. Fouling occurs in these systems when they are in contact with EDC processing streams contaminated with oxygen-containing compounds, such as aldehydes. These deposits are formed in EDC processing streams contaminated with oxygen-containing compounds while in contact with a caustic solution having a pH>7. The invention comprises adding an effective deposit-inhibiting amount of a non-enolizable carbonyl compound to the caustic solution. Preferred non-enolizable carbonyl compounds are formaldehyde, glyoxal, benzaldehyde, p-anisaldehyde, formic acid, glyoxalic acid and paraformaldehyde.

Abstract: Applicants have developed a process for inhibiting the polymerization of vinyl aromatic compound during the distillation of the vinyl aromatic compounds. The process involves adding to the vinyl aromatic compound, e.g., styrene, a nitroso compound such as N-nitroso-N, N'-di-3-pentyl-p-phenylenediamine.

Abstract: Methods and compositions for inhibiting fouling in vinyl monomers are disclosed. Alkylphosphonate esters or acids thereof are added to vinyl monomers, particularly ethylene dichloride, that are undergoing processing to inhibit fouling.

Abstract: A process for distilling a crude acrylic silane solution particularly containing impurities in a commercial scale for separating acrylic silane in the presence of a hindered phenol and/or amine as polymerization inhibitor, the process being improved by using simultaneously a dialkyldithiocarbamic acid copper and/or N-nitrosophenylhydroxylamine salt as synergistic polymerization inhibitor.

Abstract: A process including a first stage wherein a feed gas stream containing acrolein originating, for example from the gas-phase oxidation of propylene to acrolein, is fractionated into a gaseous effluent and a liquid stream in a cooling column operating such that the temperature of the liquid stream at the bottom of the column is lower than or equal to the condensation temperature of the feed gas stream, the difference in temperature not exceeding 20.degree. C. and, a second stage, wherein the gaseous effluent is condensed at a temperature that is lower than 20.degree. C., to give a liquid fraction and a purified gaseous fraction, is disclosed. An apparatus for carrying on the purification process is also disclosed.

Abstract: In a process for the separation by rectification of unsaturated carboxylic acids from solvents in which the acids were absorbed after the synthesis reaction, the rectification is briefly interrupted and the rectification column is flushed with a basic solution. The interruption is carried out at regular time intervals. The basic solution used is an aqueous solution of alkali metal and/or alkaline earth metal hydroxide, preferably NaOH, KOH, Ca(OH).sub.2 or their anhydrous oxides; alkaline polar organic solvents as amines or amides can be used, too.

Abstract: A polymerization inhibitor composition for inhibiting the polymerization of aromatic vinyl monomers at elevated temperatures comprising:(a) a benzofuroxan derivative of the formula ##STR1## wherein R is C.sub.1 -C.sub.4 alkyl or alkoxy; R.sup.1 is a nitro group; and m and n are each independently 0, 1, or 2; and(b) a solvent selected from the group consisting of toluene, xylene, ethylbenzene, vinyltoluene, divinylbenzene, alpha-methylstyrene, and a C.sub.12 -C.sub.18 hydrocarbon,and methods for inhibiting the polymerization of aromatic vinyl monomers at elevated temperatures using this composition.

Abstract: The invention provides a method for the inhibition of fouling in petrochemical processes. The method comprises adding from about 0.1 to about 10,000 parts per million sulfonated oils, sulfonated fatty acids, sulfated oils, sulfated fatty acids, or naphthalene sulfonate formaldehyde condensates to a petrochemical process to disperse water insoluble foulant into an aqueous system.

Abstract: The polymerization of a vinyl aromatic monomer such as styrene is inhibited by the addition of a composition of a benzoquinone derivative and a hydroxylamine compound.

Abstract: Compositions and methods for inhibiting the polymerization of vinyl aromatic monomers in oxygen-free processing systems are disclosed. The compositions comprise a hydroxylamine compound, a phenylenediamine compound and a vinyl aromatic monomer. The methods comprise adding to the monomer bis-N,N'(hydroxypropyl)hydroxylamine.

Abstract: A method for the prevention of fouling in a distillation train of a hydrocarbon processing unit. The method involves the precipitation of foulants contained in the hydrocarbon fluid prior to distillation. Precipitation of fouling components occurs when the liquid to be distilled is contacted with a high boiling fluid which is a non-solvent for the foulant causing species but is a solvent for the liquid that is to be distilled.

Abstract: Vinyl aromatic monomer polymerization methods utilizing a composition of 2,6-di-tert-butyl-4-methylphenol and a substituted benzoquinonediimide compound are disclosed. Preferably, the composition is employed in an amount of 1 part to 10,000 parts per million parts monomer during distillation of styrene.

Abstract: This invention relates to a blend of different isomers of a compound represented by structure I ##STR1## wherein R is C.sub.9 -C.sub.20 alkyl; wherein Y is NO.sub.2 or SO.sub.3 R' or H; wherein R' is C.sub.1 -C.sub.20 alkyl; wherein X is NO.sub.2 or C.sub.1 -C.sub.20 alkyl; and wherein R" is H or C.sub.1 -C.sub.20 alkyl, m is 2 or 3, and n is 0, 1, 2, 3, with the provisos: (1) that Y may not be H and X may not be NO.sub.2 when n=0 and (2) that when R is C.sub.9 and n=0, X and Y may not both be NO.sub.2.

Abstract: Methods for inhibiting the polymerization of vinyl aromatic monomers in oxygen-free processing systems are disclosed. The methods comprise adding from 1 to 10,000 parts of a combination of a hydroxylamine compound and a phenylenediamine compound to the vinyl aromatic monomer.

Abstract: Compositions and methods for inhibiting polymerization of vinyl aromatic monomers in oxygen-free processing systems are disclosed. The compositions comprise an oxime compound and a hydroxylamine compound and, alternatively, an oxime compound, a hydroxylamine compound and a phenylenediamine compound. The methods comprise adding either of the compositions to the vinyl aromatic monomer in an amount ranging from 1 to about 10,000 parts per million parts monomer.

Abstract: This invention is directed to a polymerization inhibitor and a polymerization inhibiting method which enables the continuous operation of a device for producing vinyl compounds over a long period of time and virtually eliminates corrosion. Further, the polymerization inhibitors according to the present invention are superior in polymerization inhibition when transferring and storing the vinyl compound products and in other cases. The polymerization inhibitor according to the present invention contains manganese dithiocarbamate or a thiuram compound as an effective component. The polymerization inhibiting method of this invention comprises individual or joint use of said inhibitors, or joint use of a copper salt, another manganese salt, or quinones in addition to said inhibitors. Further, the method may comprise jointly using copper dithiocarbamates in a manganese salt as polymerization inhibitors, or jointly using quinones in addition to the salts.

Abstract: A method of reducing the levels of impurities in aqueous monomer solutions is provided. Subjecting aqueous monomer solutions to ultraviolet radiation for from about 2 minutes to about 5 hours, reduces the level of impurities, especially carbonyl-compounds.

Abstract: In the production of maleic anhydride, a crude maleic anhydride is produced which contains acrylic acid and other by-products. The crude maleic anhydride is dissolved in a solvent and the acrylic acid is distilled off. To avoid the polymerization of the acrylic acid, an inhibitor of phenothiazine is added to the distillation process.

Abstract: In a method for reducing the fouling of a compressor of a vinyl acetate production unit having a light ends stream feed, a hindered phenol is added to the compressor feed. The method retards the loss of compressor efficiency with run time and increases the run time before clean-out is required. The hindered phenol is added in a dosage amount effective for reducing the fouling of the compressor.

Abstract: The present invention pertains to methods and compositions for inhibiting polymerization of hydrocarbons during processing and storage. The methods comprise adding an effective amount of a hydroxyalkylhydroxylamine compound to the hydrocarbon sought to be treated.

Abstract: A method for preventing fouling of ethylene dichloride distillation units which comprises treating the feed to such units with a fouling preventing amount of a composition comprising:______________________________________ INGREDIENTS WEIGHT % ______________________________________ a) An oil soluble polymethacrylate 2-15 ester which contains from between .1-25 mole % of amino alcohol ester groups with the balance of the alcohol radical of the ester group containing from C.sub.4 -C.sub.22 carbon atoms, b) a phenylene diamine compound 20-40 having the formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are the same or different and are hydrogen, C.sub.1 -C.sub.20 alkyl, C.sub.1 -C.sub.20 aryl, C.sub.1 -C.sub.20 alkaryl or C.sub.1 -C.sub.20 aralkyl, with the proviso that at least one of R.sub.1, R.sub.2, R.sub.3 or R.sub.

Abstract: A method for inhibiting fouling in an organic process stream by adding certain oximes, hydrazine, erythorbic acid, carbohydrazide, or mixtures thereof. The antifoulant is added to the organic stream as an aqueous solution.

Abstract: The purification by distillation of glycidyl (meth)acrylate containing light products containing epichlorohydrin and light impurities, and heavy impurities comprises: in a first stage, a distillation of the glycidyl (meth)acrylate to be purified is conducted in the presence of a first solvent, e.g., water, capable of forming a low boiling point heteroazeotrope with the light impurities and epichlorohydrin, so as to obtain a head fraction which consists essentially of a solvent-light products heteroazeotrope; and, in a second stage, the glycidyl (meth)acrylate thus freed from the light products is subjected to a distillation in the presence of a second solvent, e.g.

Abstract: A method of inhibiting fouling in a crude ethylene dichloride stream comprises introducing into the stream an inhibiting amount of an antifoulant selected from (A) an acylated amine (e.g., reaction product of polyisobutylene and maleic anhydride) and a polyamine (B) magnesium alkyl aryl sulfonate, and (C) a mixture of A and B.

Abstract: Compositions containing an acryloxysilane or a methacryloxysilane and an N,N-dialkylaminomethylene phenol in an amount at least sufficient to inhibit polymerization of the silane during its formation, purification and storage. Methods for producing such compositions are also provided.

Abstract: A new and improved polymerization inhibitor composition, its method of manufacture, and its use in stabilizing the distillation of acrylic acid is made possible by the pre-oxygen-activation of N-nitrosophenylhydroxylamine in combination with hydroquinone mono-methyl-ether (often referred to as p-methoxyphenol) whereupon a synergistic performance of these components is disclosed.

Abstract: A process for the production of monomeric .alpha.-cyanoacrylates by pryrolysis of poly-.alpha.-cyanoacrylates and subsequent distillation of the resulting monomeric .alpha.-cyanoacrylates.

Abstract: A method of inhibiting fouling in distillation towers, overhead lines, reflux lines, and condensers operating in a process to manufacture and purify epichlorohydrin. This method resides in treating process streams entering or exiting such towers, lines and condensers, including feed streams, reflux streams, gaseous or liquid overhead streams, with an effective antifouling amount of a C.sub.3 -C.sub.9 linear or branched alkyl substituted catechol, or mixtures thereof.

Abstract: A composition having the formula ##STR1## wherein n has an average value of one to about five, is disclosed for use in reducing or eliminating the formation of reactor scale during the polymerization of vinyl chloride and comonomers. The composition is prepared by reacting phenothiazine with formaldehyde in the presence of a liquid diluent that is a solvent for the phenothiazine, but a non-solvent for the dimer of phenothiazine and formaldehyde. The process of the invention is preferably conducted in the presence of a strong acid catalyst. The formaldehyde is preferably added slowly to the reaction mixture over the course of the reaction. The product can be filtered and dried.

Abstract: This invention relates to a method for the purification of glycidyl acrylate or glycidyl methacrylate. Specifically, the invention effects the purification by using a residual catalyst-inactivating additive and consequently produces highly purified glycidyl acrylate or glycidyl methacrylate containing substantially no epichlorohydrin and having a low chlorine content.

Abstract: Polymer formation is inhibited during the distillation of ethyl acrylate and acrylic acid produced from the reaction of ethylene and acrylic acid with sulfuric acid. In the presence of sulfur dioxide formed during the reaction, nitrogen oxide (NO) is highly effective for inhibition of polymerization fouling.

Abstract: A process for stabilizing a silicon-containing methacrylate having the formula (I): ##STR1## wherein X is Si(OCH.sub.3).sub.3, Si(OCH.sub.3).sub.2 CH.sub.3, Si(OCH.sub.3)(CH.sub.3).sub.2 or Si(CH.sub.3).sub.3 which comprises adding 2,5-di-t-butylbenzoquinone to the silicon-containing methacrylate, whereby polymerization of the silicon-containing methacrylate can be inhibited. As a result, the silicon-containing methacrylate can be stabilized without any trouble in distillation step.

Abstract: Vinylaromatic compounds are stabilized against undesired polymerization by adding to the vinylaromatic compounds small amounts of zinc or nickel salts of dialkyl dithiocarbamates, specifically p-diisopropenylbenzene can be stabilized by the use of zinc dibutyldithiocarbamate.

Abstract: Hydrocarbon processing equipment is protected against fouling during the processing of hydrocarbons at elevated temperatures by adding to the equipment small amounts of the N,N'-dimer of phenothiazine or a substituted phenothiazine.

Abstract: The present invention provides an improvement in methods for preparing and processing readily polymerizable acrylate monomers. The improvement comprises employing phenyl-para-benzoquinone, 2,5-di-phenyl-para-benzoquinone, and mixtures thereof as process inhibitors. The process inhibitors are present in a concentration of about 50 to 3000 ppm, preferably about 250 to 2000 ppm, and most preferably about 500 ppm.

Abstract: Ferric iron is removed from chlorinated hydrocarbons having less than 6 carbon atoms per molecule by intimately contacting the latter with an oil that comprises one or more hydrocarbons having at least 6 concatenated aliphatic carbon atoms per molecule. The hydrocarbon oil is present in an amount sufficient to interact with a major portion of the ferric iron. The resulting mixture of the chlorinated hydrocarbon stream and the hydrocarbon oil is heated simultaneously with the intimate contacting, and a precipitate is allowed to form. The chlorinated hydrocarbon stream is then separated from the hydrocarbon oil and from the precipitate, and the precipitate is subsequently separated from the hydrocarbon oil, which may be recycled and re-used.

Abstract: A new and improved contact lens is provided and is made by a process which uses a distillation step with an addition of a carbon decolorizing agent to the solution being distilled. The carbon decolorizing agent prevents curdling and removes impurities in the distillation step. The result is a contact lens with a very high water content and with good oxygen permeability characteristics.

Abstract: A method and apparatus for distilling readily polymerizable liquid such as readily polymerizable monomers without causing the formation of an undesirable polymerization product is disclosed. This distillation is effected by(a) vaporizing the polymerizable liquid from a liquid phase containing the same in an evaporator by externally heating the liquid phase;(b) converting the vapor of the polymerizable liquid to a superheated state by externally heating, and introducing the vapor of the polymerizable liquid to the inlet of a condenser, while the vapor is maintained at the superheated state; and, then,(c) condensing the vapor in the condenser, while a portion of the condensed fraction is circulated to the inlet of the condenser, whereby the condensation surface thereof is wetted.

Abstract: In a process for producing a 2-hydroxyalkyl acrylate or methacrylate which comprises esterifying acrylic or methacrylic acid with an alkylene oxide having 2 to 4 carbon atoms in the presence of an esterification catalyst and distilling the resulting reaction mixture in a distillation column, the improvement wherein the vapor of the ester monomer from the distillation column, while being maintained in the superheated state, is introduced into a condenser of the gas-liquid direct contact type whose inner wall corresponding to its gas inlet portion is kept at a temperature below the boiling point of the ester at the operating pressure, to contact it directly with a concurrently flowing spray liquid of the ester-precooled to a temperature below the boiling point of the ester at the operating pressure, whereby said vapor is condensed to a liquid at said temperature below the boiling point of the ester at the operating pressure.

Abstract: Nitrogen oxides have been found to be effective to inhibit during distillation the vinyl polymerization of a 2-isocyanatoalkyl ester of an unsaturated carboxylic acid. For example, crude 2-isocyanatoethyl methacrylate was sparged with nitric oxide in nitrogen gas during distillation at 90.degree. C., so as to effect a concentration of nitric oxide in the gas phase of 376 parts per million by weight. Essentially pure 2-isocyanatoethyl methacrylate was recovered in 70 percent yield.

Abstract: In a process for producing acrylic acid which comprises contacting with water an acrylic acid-containing reaction product gas which has been obtained by the catalytic vapor phase oxidation of an olefinic compound of a general formula, CH.sub.2 .dbd.CHX, wherein X represents at least one group selected from the group consisting of CH.sub.

Abstract: A normally liquid hydrocarbon having a minimum boiling point of about 425.degree. F. is utilized to provide the liquid seal in a vacuum pump which intakes a gaseous light ends stream resulting from a process for the production of ethyl acrylate by the reaction of ethylene with acrylic acid in the presence of a sulfuric acid catalyst. Upon contact in the vacuum pump, the gaseous light ends are partially absorbed into the normally liquid hydrocarbon, with the normally liquid hydrocarbon being recovered by fractionation.

Abstract: The presence of solid polymer in distillation columns and their associated reboilers used for the recovery of methacrylic and acetic acids produced by the oxidation of methacrolein may be minimized by the use of inhibitors and introduction of molecular oxygen at a rate above a predetermined threshold value, which is a function of the operating temperature of the equipment. For a given temperature, the amount of solids has been found to be greatly increased below the threshold value of oxygen, while above the threshold value, the rate of appearance of solids has been found to be minimized and further increases in oxygen rate have only a minimal effect. At a typical operation temperature of 120.degree. C., the threshold value of about 0.1 SLH O.sub.2 /100 gm of liquid. A gas containing a relatively high concentration of oxygen is preferred.

Abstract: Apparatus and processes are disclosed for converting sensitive organic compounds such as acrolein, methacrolein, acrylic acid and methacrylic acid from liquid to vapor in admixture with a gas stream at super-atmospheric pressures with minimum decomposition and substantially without polymer formation. The acrolein and methacrolein partial pressures being up to super-atmospheric and those of acrylic and methacrylic acids up to about an atmosphere.An apparatus and a process are also disclosed for transferring a sensitive organic material in an energy-efficient manner from a low-pressure, high-temperature gas-vapor stream to a solvent for the sensitive material, and then to another gas stream at increased pressure.

Abstract: A crude olefin oxide containing high-boiling ingredients is distilled at a pH of 4 to 7 in the presence of a nonvolatile neutral or weakly basic alkali metal or alkaline earth metal salt or hydroxide to separate the olefin oxide from the high-boiling ingredients. This permits the prevention of the polymerization of the olefin oxide and its conversion to the corresponding glycol.

Abstract: In a process for preparing diacetoxybutene by subjecting butadiene, acetic acid and oxygen to reaction, the discharge gas from the reaction system or purification system, containing butadiene and/or acetic acid, is treated by contacting with diacetoxybutene and/or diacetoxybutane (absorbent) to allow butadiene and/or acetic acid to be absorbed by said absorbent. A part of the diacetoxybutene separated in a distillation tower from the reaction product solution containing diacetoxybutene produced by said three-component reaction can be used as said absorbent. In this case, butadiene and/or acetic acid can be recovered from said discharge gas by supplying the absorption solution into said distillation tower. Also usable as said absorbent is diacetoxybutane obtained by hydrogenation of diacetoxybutene.