Abstract: A method and installation for energy densification of a material to obtain pyrolytic oils for energy. The method includes preconditioning the material by heating and drying to raise the material temperature close to 100° C. and a relative humidity not exceeding about 10%; pyrolyzing the material that is subsequently caused to flow through a substantially hermetic reactor containing at least one transfer screw or vibrating tube heated by the Joule effect, the material heated progressively in the range of 300° C. to 850° C., the electrical power passing through the transfer screw or the vibrating tube for providing heating regulated as a function of the material in order to obtain the desired temperature level during the transit time of the material through the reactor; extracting pyrolysis gas from a high portion of the reactor for rapid recondensation in a vertical condenser; and recovering pyrolytic oils from a low portion of the vertical condenser.

Abstract: The invention relates to a retarder composition for the control of unwanted polymerization reactions during the production and processing of ethylenically unsaturated compounds, the composition comprising at least one di-substituted quinone compound and at least one hydroxylamine compound. Optionally, the composition also comprises at least one stable free radical nitroxyl compound and one or more formulation adjuvants. The invention also envisages a process stream comprising at least one ethylenically unsaturated compound, and a method for the prevention of unwanted polymerization reactions during the production and processing of ethylenically unsaturated compounds. The composition has been found to be far more effective than expected, given that the individual components show little or no efficacy when used alone, and poses much less hazard to humans than the compositions of the prior art.

Abstract: Controlling the formation of crystalline hydrates in various fluid systems, most notably, gas and oil transmission pipeline systems by contacting the systems with certain polymers or polymers associated with solid particles. The polymers useful are chelating polymers capable of interacting with charged gaseous molecules such as carbon dioxide, by removing the carbon dioxide, or more practically by scavenging for the carbon dioxide, to prevent the methane or ethane hydrate structures from forming since they require carbon dioxide to stabilize their structures.

Abstract: Elimination and/or mitigation of fouling in a vapor transport systems, such as vent lines and scrubber feed lines may be accomplished using an antifouling additive. The method for employing the antifouling additive includes introducing into the vapor transport system an additive including a polar solvent and corrosion inhibitor wherein: the vapor transport system is substantially water free; the vapor transport system is used to transport acidic materials; the additive is a liquid at vapor transport system operating conditions; and the additive is stable at the vapor transport system operating conditions.

Abstract: The present invention is a method of reducing the formation of fouling deposits occurring in a caustic scrubber used to remove acid gases comprising: a) providing a caustic scrubber fed with an alkaline aqueous solution comprising essentially one or more of NaOH, KOH or LiOH, b) providing an olefin-containing hydrocarbon stream, contaminated with oxygenated compounds and acid gases, and said oxygenated compounds are capable to make polymeric fouling deposits in the presence of the alkaline solution of the scrubber, c) sending the above hydrocarbon stream to the caustic scrubber to recover an olefin-containing hydrocarbon stream essentially free of acid gases, wherein, d) an efficient amount of a solvent capable to reduce the formation of fouling deposits is introduced in the caustic scrubber and/or in the alkaline solution fed to the scrubber, e) the liquid outlet of the scrubber is sent to means to separate the solvent from the alkaline solution, and wherein the caustic scrubber has several stages with vario

Abstract: Elimination and/or mitigation of fouling in a vapor transport systems, such as vent lines and scrubber feed lines may be accomplished using an antifouling additive. The method for employing the antifouling additive includes introducing into the vapor transport system an additive including a polar solvent and corrosion inhibitor wherein: the vapor transport system is substantially water free; the vapor transport system is used to transport acidic materials; the additive is a liquid at vapor transport system operating conditions; and the additive is stable at the vapor transport system operating conditions.

Abstract: New tertiary amine salts are useful as gas hydrate inhibitors in oil and gas production and transportation. These tertiary amine salts give very good separation from an emulsion, are economic and have reduced toxicity concerns.

Abstract: Catalytic methods for the production of saturated hydrocarbons with 2 to 5 carbon atoms per molecule by conversion of small hydrocarbon halides and/or hydrogenation of carbonaceous material are disclosed that result in high yield of saturated C2 to C5 hydrocarbons at reduced corrosion of the reactors and in good lifetime of the catalyst. The methods are performed in the presence of a Lewis acid comprising catalyst and in the absence of oxygen or oxygen containing compounds, whereby an upper limit of at most 50 parts per million mass of oxygen or oxygen containing compounds can be tolerated.

Abstract: A processes is provided to inhibit or limit the decomposition of a halide-containing olefin oligomerization catalyst system during recovery of an oligomerization product. The process includes deactivation of an olefin oligomerization catalyst system present in an olefin oligomerization reactor effluent stream by contact with an alcohol under conditions that minimize potential for deactivated catalyst system decomposition. Such conditions include minimization of the water content of the deactivation agent and concentration of the deactivation agent.

Abstract: The invention relates to olefin oligomerization methods and methods for reducing/inhibiting fouling in olefin oligomerization reactions comprising: contacting, in an oligomerization reactor (e.g., under oligomerization conditions), an alpha-olefin feed, a catalyst having an olefin selectivity of at least 90 mol % to a desired oligomerization product, a polymer anti-foulant, and optionally a diluent; selectively producing an effluent comprising the desired oligomerization product, unreacted olefin, and alpha-olefin-based polymer byproduct that causes fouling. The amount of polymer anti-foulant can be chosen to limit fouling to ?20 g/kg desired oligomerization product, to remediate ?3 grams fouled polymer/kg desired oligomerization product, and/or to reduce/inhibit polymer fouling by ?10% over a selective oligomerization with substantially no added polymer anti-foulant. Advantageously, desired oligomerization product so obtained can also be polymerized/copolymerized with an alpha-olefin such as ethylene.

Abstract: The quaternary ammonium compound described by general formula 1 below (wherein R1, R2 and R3 are the same or different hydrocarbon radicals with 1 to 4 carbon atoms, and n is an integer between 1 and 10) is used as a metal corrosion inhibitor. With this metal corrosion inhibitor, it is possible even with the addition of small quantities to adequately prevent corrosion of metal in a steam generating unit or petroleum refining or petrochemical process unit. Moreover, (?-hydroxyethyl)trimethylammonium hydroxide is used as a hydrogen chloride formation inhibitor for a crude oil atmospheric distillation unit. With this hydrogen chloride formation inhibitor, it is possible to prevent the formation of hydrogen chloride itself in a crude oil atmospheric distillation unit without having any adverse effect on the catalyst.

Abstract: The invention provides a method to avoid catalyst damage and achieve longer catalyst life by selecting appropriate materials for reactor spacers, liners, catalyst binders, and supports, in particular, by not using crystalline silica-containing and high phosphorus-containing materials, if the presence of even small amount of steam is anticipated. In addition, alkali metals and alkaline earth metals are avoided due to potential damage to the catalyst.

Abstract: A method for inhibiting the formation of fouling materials including contacting hydrocarbon media containing aldehyde compounds with an antifoulant while treating the hydrocarbon media with a basic wash. The antifoulant includes a reducing sugar.

Abstract: The invention provides compounds of the formula 1 in which A is a C2- to C4-alkylene group x is from 1 to 100 R1 is C1-C30-alkyl, C2-C30-alkenyl, C7-C30-alkylaryl R2 is an aliphatic, cycloaliphatic or aromatic radical which contains at least one structural unit of the formula 2 ?and y is from 0 to 100, with the proviso that y is from 1 to 100 when R2 is of the formula 2, and their use in amounts of from 0.01 to 2% by weight for preventing the formation of gas hydrates in aqueous phases which are in contact with a gaseous, liquid or solid organic phase.

Abstract: Corrosion of metallic tubulars in an oil, gas or geothermal well may be inhibited by introducing into the well a dithiazine of the formula: wherein R is selected from the group consisting of a C1 to C10 saturated or unsaturated hydrocarbyl group or a C1 to C10 ?-hydroxy saturated or unsaturated hydrocarbyl group. The dithiazine may be isolated from a whole spent fluid formed by reaction of hydrogen sulfide and a triazine. Alternately, the whole spent fluid containing the dithiazine may be introduced into the well. In addition, the dithiazine or whole spent fluid may be formulated with at least one component selected from alkyl, alkylaryl or arylamine quaternary salts; mono or polycyclic aromatic amine salts; imidazoline derivative or a quaternary salt thereof; a mono-, di- or trialkyl or alkylaryl phosphate ester; or a monomeric or oligomeric fatty acid.

Abstract: Corrosion of metallic tubulars in an oil, gas or geothermal well may be inhibited by introducing into the well a dithiazine or dithiazine of the formula: wherein R is selected from the group consisting of a C1 to C12 saturated or unsaturated hydrocarbyl group or a C1 to C10 ?-hydroxy saturated or unsaturated hydrocarbyl group; R1 is selected from the group consisting of a C1-C24 straight chain or branched alkyl group or a C1-C24 arylalkyl; R2 is selected from the group consisting of X-R4-X, R4 being a C1-C6 alkyl group; and X is chlorine, bromine or iodine. The dithiazine may he isolated from a whole spent fluid formed by reaction of hydrogen sulfide and a triazine. Alternately, the whole spent fluid containing the dithiazine may be introduced into the well. The dithiazines of formulae (II) and (III) are quaternized derivatives of the dithiazine of formula (I).

Abstract: Embodiments of the invention relate to a process for providing a pumpable hydrate slurry in a hydrocarbon pipeline fluid mixture having a water-cut greater than about 50 volume percent. In one or more embodiments the process comprises treating the fluid mixture with an anti-agglomerant and adding water to the fluid mixture in an amount sufficient to lower the gas-water ratio sufficiently to achieve a pumpable hydrate slurry. Also disclosed are methods for producing hydrocarbons utilizing a process for providing a pumpable hydrate slurry in a hydrocarbon pipeline fluid mixture having a water -cut greater than about 50 volume percent.

Abstract: A method for inhibiting the premature polymerization and the polymer growth of ethylenically unsaturated monomers is disclosed wherein the method comprises adding to said monomers an effective amount of at least one hydrogen donor or electron acceptor. In a preferred embodiment, the hydrogen donor or electron acceptor is used in combination with a stable nitroxyl free radical.

Abstract: In order to transport hydrates in suspension in a fluid comprising water, gas and a liquid hydrocarbon, at least one non-polluting composition consisting essentially of a mixture comprising at least one ester associated with a non-ionic co-surfactant of the polymerized (dimer and/or trimer) carboxylic acid type is incorporated into said fluid. The composition is generally introduced in a concentration of 0.1% to 5% by weight with respect to the liquid hydrocarbon.

Abstract: A method for processing asphaltenes is disclosed. The method can include separating asphaltenes from an asphaltene-containing composition and oxidizing the separated asphaltenes to form oxidation products. Alternatively, the method can include oxidizing asphaltenes within an asphaltene-containing composition without first separating the asphaltenes. Once formed, the oxidation products can be combined with other hydrocarbons. The amount of oxidation can be limited to an amount sufficient to produce a mixture suitable for the desired application. This method can be used to upgrade asphaltenes from a variety of sources, including oil sands. The oxidation step can be performed, for example, by introducing an oxidizing agent and, in some cases, a catalyst into the asphaltenes. A solvent or miscibility agent also can be introduced to improve mixing between the oxidizing agent and the asphaltenes.

Abstract: A quench exchanger and quench exchanger tube with increased heat transfer area on the process side of the tube are provided. The exchanger provides increased heat transfer efficiency relative to a fixed tube length and at the same time eliminates stagnant and low velocity areas as well as recirculation eddies. The tubes incorporate a fin profile on the process side of the tube with alternating concave and convex surfaces. Additionally, the fins are preferably aligned with the tube center line as opposed to being twisted or spiraled.

Abstract: Process for the production of vinyl-aromatic monomers which comprises: a) feeding an aromatic stream and an olefinic stream to alkylation; b) feeding the reaction product coming from the alkylation section to a first separation section; c) recovering the mono-alkylated aromatic hydrocarbon from the first separation section; d) feeding the mono-alkylated aromatic product to a dehydrogenation section; e) cooling and condensing the reaction gases in the shell of one or more heat exchangers; f) feeding the reaction product coming from the dehydrogenation section to a second separation section; g) recovering the stream of vinyl-aromatic monomer.

Abstract: A process for the solution polymerization of olefins with improved on-stream time is provided. The solution polymerization process of the current invention comprises a method for the on-line removal of foulant material from one or more heat exchangers downstream of a polymerization reactor. Removal of foulant material is accomplished by deliberately applying a positive pressure differential across a heat exchanger. In the process of the current invention, reactor shut down is not required for the purpose of cleaning foulant material from a heat exchanger.

Abstract: The invention concerns a method for reducing coking on the metal walls of a reactor cracking hydrocarbons or other organic compounds and on the metal walls of a heat exchanger placed downstream of the cracking reactor, whereby the metal surfaces coming into contact with the organic substance to be cracked are pre-treated with a water vapor stream containing at least silicon and at least a sulphur compound.

Abstract: Use of diaminopropanes, or of a composition thereof as a dispersing agent to prevent the formation or remove already formed deposits of ammonium salt in hydrocarbon process plants, such as petrochemical or refinery plants.

Abstract: The present invention is directed toward reducing corrosion in a methanol-to-olefin (MTO) effluent processing system, and particularly in the condensate removal system thereof, by injecting a neutralization agent into one or more target regions of the MTO effluent processing system. The neutralization agent ensures that any localized condensation in the MTO effluent processing system, particularly in the condensate removal system, occurs under basic conditions and that any acidic condensable components are neutralized. The invention is also directed to monitoring corrosion in an MTO effluent processing system and to monitoring the pH of localized corrosion sites in order to ensure proper neutralization of any acidic condensation formed therein.

Abstract: The invention provides compounds of the formula 1 in which A is a C2- to C4-alkylene group x is from 1 to 100 R1 is C1-C30-alkyl, C2-C30-alkenyl, C7-C30-alkylaryl R2 is an aliphatic, cycloaliphatic or aromatic radical which contains at least one structural unit of the formula 2 ?and y is from 0 to 100, with the proviso that y is from 1 to 100 when R2 is of the formula 2, and their use in amounts of from 0.01 to 2% by weight for preventing the formation of gas hydrates in aqueous phases which are in contact with a gaseous, liquid or solid organic phase.

Abstract: A method and an amide composition used therein for inhibiting, retarding, mitigating, reducing, controlling and/or delaying formation of hydrocarbon hydrates or agglomerates of hydrates. The method may be applied to prevent or reduce or mitigate plugging of conduits, pipes, transfer lines, valves, and other places or equipment where hydrocarbon hydrate solids may form under the conditions. At least one amide compound is added into the process stream, where the compound may be mixed with another compound selected from amino alcohols, esters, quaternary ammonium, phosphonium or sulphonium salts, betaines, amine oxides, other amides, simple amine salts, and combinations thereof.

Abstract: Amine and amine blend compositions neutralize acid environments in distillation overheads of hydrocarbon processing facilities. The neutralizers are composed of certain combinations of amines which are relatively stronger bases and more resistant to hydrochloride salt formation. The amines, when blended together, provide greater neutralization of condensed water present without increased potential for corrosive hydrochloride salt formation.

Abstract: A specific nonionic surfactant is added to a component mainly comprising hydrocarbons before passing through a heat exchanger in a petrochemical plant or a polyolefin production plant, whereby fouling of the heat exchanger can be efficiently prevented, that is, the performance of the heat exchanger can be prevented from being deteriorated, and long-term operation is feasible without sacrificing the speed of production. The nonionic surfactant is preferably a polyoxyalkylene compound represented by the general formula [I] below, more preferably a compound represented by the general formula [II] below. R1—O—[CH2—CH(R3)—O]k—R2[I] wherein R1, R2 and R3 are selected from a hydrogen atom, a C1 to C20 alkyl group, a C6 to C20 aryl group and a C1 to C20 acyl group, and may be the same or different from each other. HO—(CH2CH2O)m—[CH2CH(CH3)O]n—(CH2CH2O)pH[II] wherein m, n and p each represent the average number of repeating units, and m is in the range of 1 to 20, n is 2 to 50 and p is 1 to 20.

Abstract: The invention relates to the use of polymers which contain between 1 and 99 mol-% structural units of formula 1, wherein R1 represents hydrogen or C1-C6 alkyl, R2 represents C1-C24-alkyl, C2-C24-alkylene or a C6-C18-aryl radical, which can be substituted with a C1-C12-alkyl group, A represents identical or different C2-C4 alkylene radicals and, x, represents whole number from 2-40 in quantities from 0.01-2 wt-%, in quantities from 0.01 to 2 wt-%, in relation to the aqueous phase. The polymers can be used as gas hydrate inhibitors.

Abstract: There is disclosed a process for producing an ?-olefin oligomer by subjecting an ?-olefin to oligomerization reaction in the presence of a catalyst and an organic solvent which comprises the step of spraying a solvent containing the organic solvent in the form of a linear or bar-like pressure fluid toward a wall surface of a vapor phase portion of a reactor from a nozzle fitted within a space of the vapor phase portion of the reactor to conduct the oligomerization reaction while cleaning the wall surface of the vapor phase portion of the reactor. In the production process of the present invention, it is possible to effectively prevent deposition of polymers onto the wall surface of the vapor phase portion of the reactor and stably operate the reactor for a long period of time.

Abstract: A method of dispersing, dissolving, or reducing the viscosity of hydrocarbon foulants including heavy oil, tars, asphaltenes, polynuclear aromatic hydrocarbons, coke, polymers, light oil, oxidized hydrocarbon and thermal decomposition products, and the like in fluids in contact with hydrocarbon processing equipment comprising contacting the foulant with an effective amount of a halogen-free organic solvent having a density greater than water at the processing temperature.

Abstract: The present invention is directed toward reducing corrosion in a methanol-to-olefin (MTO) effluent processing system, and particularly in the condensate removal system thereof, by injecting a neutralization agent into one or more target regions of the MTO effluent processing system. The neutralization agent ensures that any localized condensation in the MTO effluent processing system, particularly in the condensate removal system, occurs under basic conditions and that any acidic condensable components are neutralized. The invention is also directed to monitoring corrosion in an MTO effluent processing system and to monitoring the pH of localized corrosion sites in order to ensure proper neutralization of any acidic condensation formed therein.

Abstract: According to the present invention, there is provided a process for inhibiting the polymerization of an aromatic vinyl compound which is capable of efficiently inhibiting the polymerization of an aromatic vinyl compound not only in an initial stage but also over a long term in the stage of producing, purifying, storing or transporting the aromatic vinyl compound, and which is excellent in handling. The present invention relates to a process for inhibiting the polymerization of an aromatic vinyl compound which requires the step of adding a 2-nitrophenol compound in combination with a sulfonic acid compound to the aromatic vinyl monomer during the stage of producing, purifying, storing or transporting the aromatic vinyl compound.

Abstract: A method for inhibiting formation of hydrocarbon hydrates in mixtures of water and a hydrate-forming guest molecule involves adding a reaction product to the mixtures in an effective amount to inhibit formation of the hydrocarbon hydrates under conditions otherwise effective to form the hydrocarbon hydrates in the absence of the reaction product. The product is made by the reaction of first reactant that is an amine or polyamine, or alcohol or polyalcohol, with a second, aldehyde reactant and a third reactant that is an alcohol or polyalcohol or, an amide or polyamide. Preferably, if the first and third reactants are both an alcohol or both a polyalcohol, they are not the same. A non-limiting example of a suitable amine would be a fatty alkyl amine, while formaldehyde would be a non-limiting of a suitable aldehyde and polyacrylamide would be a suitable third reactant.

Abstract: The present invention relates to a method for determining the source of fouling in petroleum thermal conversion process units. More particularly, the invention distinguishes whether fouling occurs due to feed entrainment of small feed droplets or vapor phase condensation.

Abstract: Dialkyl polysulfides can be added to hydrocarbon gas fed streams for alkene steam crackers for the petrochemical industry. The polysulfides act as sulfiding agents for surfaces of the steam crackers and thereby reduce coking and CO generation. A preferred polysulfide is a di-t-butyl polysulfide. Such compounds tend to have lower vapor pressure, reasonable viscosities, and are relatively nonflammable as compared to the lower molecular weight sulfur containing compounds.

Abstract: The present invention is a process for removing catalyst fines from a reactor effluent stream that has catalyst fines therein. The process comprises withdrawing the reactor effluent stream from the reactor. The reactor effluent stream is transported in a first conduit to a quench device and is quenched to form a quenched effluent stream and a liquid fraction containing a majority of the catalyst fines. The liquid fraction is transported in a second conduit to a solids separation device. The conditions under which the catalyst fines are moved prevent accumulation of catalyst fines in the catalyst fines process steps.

Abstract: Quinone methide derivatives such as 4-benzylidene-2,6-di-tert-butyl-cyclohexa-2,5 dienone are used to inhibit styrene monomer polymerization in the dehydrogenator portion of a styrene monomer production system. The inhibitor contacts the dehydrogenation effluent and does not partition in substantial amounts to the aqueous phase that is separated in the phase separator.

Abstract: Inhibitor blends that include both nitrosophenols and nitrosoanilines, optionally in combination with air or oxygen, reduce the premature polymerization of ethylenically unsaturated monomers. unsaturated monomers.

Abstract: The present invention relates to a process for pyrolysis of hydrocarbons for olefin preparation, and particularly to a process for pyrolysis of hydrocarbons comprising pyrolyzing paraffin hydrocarbons in the presence of steam to prepare olefins, where the pyrolysis is conducted in a pyrolysis reaction tube in which a porous inorganic substance with a pore diameter of 1 ?m˜5 mm, a porosity of 10˜80%, and a maximum specific surface area of 0.1 m2/g is inserted or filled. According to the present invention, in the hydrocarbon pyrolysis process, the porous inorganic substance is inserted or filled into the pyrolysis reaction tube, and thus the olefin yield can be improved compared to the conventional pyrolysis processes, a continuous operation period can be prolonged, and a life cycle of the pyrolysis reaction tube can be prolonged.

Abstract: Disclosed herein is a method for inhibiting the premature polymerization of ethylenically unsaturated monomers comprising adding to said monomers an effective amount of at least one inhibitor selected from the group consisting of C-nitrosoaniline and quinone imine oxime compounds. Also disclosed is a composition of matter comprising: A) an ethylenically unsaturated monomer and B) an effective inhibiting amount, sufficient to prevent premature polymerization during distillation or purification of said ethylenically unsaturated monomer, of at least one inhibitor selected from the group consisting of C-nitrosoaniline and quinone imine oxime compounds used together with an effective amount of oxygen or air to enhance the inhibiting activity of said inhibitor.

Abstract: A method for inhibiting the formation of gas hydrates within a fluid comprising a gaseous hydrocarbon phase, a liquid hydrocarbon phase and an aqueous phase which method comprises mixing a polymeric emulsifier and optionally a non-ionic non-polymeric co-emulsifier with the fluid prior to subjecting the fluid to conditions under which gas hydrates can be formed so as to generate a water-in-oil emulsion comprising a discontinuous aqueous phase, a continuous liquid hydrocarbon phase and a substantially gas impermeable interfacial layer comprising said polymeric emulsifier and optionally said non-ionic non-polymeric co-emulsifier wherein the aqueous phase is distributed in the continuous liquid hydrocarbon phase in the form of droplets and the substantially gas impermeable interfacial layer encapsulates said droplets.

Abstract: In a process for reducing the formation of polymers during side-chain alkylation or side-chain alkenylation of alkylaromatic compounds by reaction with olefins or diolefins in the presence of an alkali metal catalyst followed by distillation in order to isolate the alkylated or alkenylated compound, the alkali metal is present in the catalyst on an inorganic support, and the catalyst is mechanically separated from the reaction mixture after the reaction and before the distillation.

Abstract: A method of inhibiting fouling and viscosity increase in hydrocarbon streams including ethylenically unsaturated monomers is disclosed. The method includes the step of adding to the hydrocarbon stream an effective amount of one or more quinone methides of the formula: wherein R1, R2, and R3 are independently selected from the group consisting of H, —OH, —SH, —NH2, alkyl, cycloalkyl, heterocyclo, and aryl.

Abstract: A method of minimizing the formation of polymers and other heavy molecular weight products upon heating of a hydrocarbon stream in a hydroconversion process is described. Specifically, sufficient hydrogen-containing gas is added to the hydrocarbon stream before heating to reduce its fouling tendency. The hydrogen-containing gas is added in an amount less than about 500 standard Cubic Feet per Barrel (SCFB). preferably less than about 100 SCFB and more preferably less than about 50 SCFB.

Abstract: Disclosed herein is a method for inhibiting the premature polymerization of ethylenically unsaturated monomers comprising adding to said monomers an effective amount of at least one inhibitor selected from the group consisting of C-nitrosoaniline and quinone imine oxime compounds. Also disclosed is a composition of matter comprising: A) an ethylenically unsaturated monomer and B) an effective inhibiting amount, sufficient to prevent premature polymerization during distillation or purification of said ethylenically unsaturated monomer, of at least one inhibitor selected from the group consisting of C-nitrosoaniline and quinone imine oxime compounds used together with an effective amount of oxygen or air to enhance the inhibiting activity of said inhibitor.

Abstract: Disclosed herein is a method for inhibiting the premature polymerization of ethylenically unsaturated monomers comprising adding to said monomers an effective amount of: A) at least one first inhibitor selected from the group consisting of C-nitrosoaniline compounds; and B) at least one second inhibitor selected from the group consisting of quinone alkides, nitroaromatic compounds, hydroxylamine compounds, phenylenediamine compounds, quinone compounds, and hydroquinone compounds. Also disclosed is a composition of matter comprising: A) at least one member selected from the group consisting of C-nitrosoaniline compounds; and B) at least one member selected from the group consisting of quinone alkides, nitroaromatic compounds, hydroxylamine compounds, phenylenediamine compounds, quinone compounds, and hydroquinone compounds.

Abstract: The invention relates to the use of compounds of the formula (1) in which R1 is C1- to C24-alkyl, C2- to C24-alkenyl or a C6- to C18-aryl radical which may be substituted by a C1- to C24-alkyl group, R2, R3 independently of one another, are hydrogen, C1- to C18-alkyl, or C8- to C7-cycloalkyl, or R2 and R3, including the nitrogen atom to which they are bonded, form a ring of 4 to 8 ring atoms, in which oxygen or nitrogen atoms may also be present in addition to carbon. A are identical or different C2- to C4-alkylene radicals, B is C1- to C7-alkylene, and n is an integer from 1-40, as gas hydrate inhibitors.