Abstract: The invention relates to a process for producing a new styrene catalyst from a spent styrene catalyst.

Abstract: A dehydrogenation catalyst is described that comprises an iron oxide, an alkali metal or compound thereof, and rhenium or a compound thereof. A process for preparing a dehydrogenation catalyst comprising preparing a mixture of iron oxide, an alkali metal or compound thereof, and rhenium or a compound thereof is also described. Additionally, a dehydrogenation process using the catalyst and a process for preparing polymers are described.

Abstract: Improved methods and related apparatus are disclosed for efficiently recovering the heat of condensation from overhead vapor produced during separation of various components of dehydrogenation reaction effluent, particularly in ethylbenzene-to-styrene operations, by the use of at least a compressor to facilitate azeotropic vaporization of an ethylbenzene and water mixture within a preferred range of pressure/temperature conditions so as to minimize undesired polymerization reactions.

Abstract: The invention relates to a method for producing unsaturated hydrocarbons. According to said method, in a first step, a hydrocarbon, especially a mixture which contains alkanes, essentially no water, and can contain water vapour, is continuously guided through a first catalyst bed provided with standard dehydration conditions. Liquid water, water vapour and a gas containing oxygen are then added to the reaction mixture obtained in the first step and, in a second step, the reaction mixture obtained is then continuously guided through another catalyst bed for oxidising hydrogen and for further dehydrating hydrocarbons. The first catalyst bed can be heated and the heating in the first step is then preferably regulated in such a way that an essentially isothermic operating mode is created.

Abstract: A manufacturing plant for carrying out a process for the catalytic dehydrogenation of a first unsaturated hydrocarbon to form a second unsaturated hydrocarbon which has one olefinically unsaturated bond more than the first unsaturated hydrocarbon and otherwise an unchanged carbon skeleton, which process comprises: contacting in a first step a feed comprising the first unsaturated hydrocarbon with a first dehydrogenation catalyst having a temperature parameter T1 and a selectivity parameter S1, and contacting in a second step a reaction product of the first step comprising the first unsaturated hydrocarbon and the second unsaturated hydrocarbon with a second dehydrogenation catalyst having a temperature parameter T2 and a selectivity parameter S2, such that T1<T2 and S1<S2.

Abstract: Process for production of styrene by dehydrogenation of ethylbenzene in a reactor system comprising a dehydrogenation reactor and a fast riser catalyst regenerator.

Abstract: High temperature treatment of graphite nanofibers to increase their catalytic activity. The heat treated graphite nanofiber catalysts are suitable for catalyzing chemical reactions such as oxidation, hydrogenation, oxidative-dehydrogenation, and dehydrogenation.

Abstract: Described is a method for operating and shutting down a dehydrogenation reactor that contains a volume of dehydrogenation catalyst. After termination of the introduction of a dehydrogenation feed into the dehydrogenation reactor that is operated under dehydrogenation reaction conditions, a first cooling fluid comprising steam is introduced into the reactor for a first time period sufficient to cool the dehydrogenation catalyst contained in the dehydrogenation reactor to a second temperature. The introduction of the first cooling fluid is terminated followed by the introduction of a second cooling fluid for a second time period sufficient to cool the dehydrogenation catalyst contained in the dehydrogenation reactor to a third temperature that allows for the handling and removal of the dehydrogenation catalyst from the dehydrogenation reactor.

Abstract: One aspect of the invention relates to a dehydrogenation catalyst composite containing alumina, chromium oxide, lithium oxide, and sodium oxide. The invention also relates to methods of making the dehydrogenation catalyst composite. Another aspect of the invention relates to method of dehydrogenating a dehydrogenatable hydrocarbon involving contacting the dehydrogenatable hydrocarbon with a dehydrogenation catalyst composite containing alumina, chromium oxide, lithium oxide, and sodium oxide to provide a dehydrogenated hydrocarbon, such as an olefin.

Abstract: A process for the dehydrogenation of a C2 or C3 alkyl aromatic compound to a corresponding vinyl aromatic compound in a tubular reactor incorporating a spiral flow path. Preferred embodiments of the invention provide processes for the production of styrene or divinylbenzene by the catalytic dehydrogenation of ethylbenzene or diethylbenzene, respectively. A feedstock containing a C2 or C3 alkyl aromatic and steam is supplied into the inlet of a tubular reactor containing a dehydrogenation catalyst and comprising a hydrogen permeable outer wall. The alkyl aromatic compound is dehydrogenated to a corresponding vinyl aromatic compound with the attendant production of hydrogen. The feedstock and products of the dehydrogenation reactor are flowed along a longitudinal spiral flow path providing for an outward radial flow of hydrogen to provide a pressure gradient through the hydrogen permeable outer wall of the reactor with the flow of hydrogen therethrough. Hydrogen is removed from the outer wall of the reactor.

Abstract: A process is described for the dehydrogenation of ethylbenzene to styrene in a fluid-bed reactor-regenerator system, which uses a catalyst based on iron oxide supported on a modified alumina and promoted with further metal oxides.

Abstract: Process for the catalytic dehydrogenation of a C2 or C3 alkyl aromatic in which a feedstock containing the alkyl aromatic and steam is supplied into the inlet of a tubular reactor containing a dehydrogenation catalyst. Within the reactor, the feedstock flows through at least a portion of the reactor along a spiral flow path extending longitudinally of the reactor. The resulting vinyl aromatic product is then recovered from a downstream or outlet section of the reactor. The spiral flow path through which the feedstock is passed is located at least adjacent the inlet side of the reactor and at least a portion of the spiral flow path contains a particulate dehydrogenation catalyst. The spiral flow path may extend throughout a major portion of the elongated tubular reactor and may contain a particulate dehydrogenation catalyst in a substantial portion there.

Abstract: An economical and industrial method for the dehydrogenation of triisopropyl benzene can be provided by carrying out the reaction employing a solid catalyst having an iron compound and potassium compound as major components or an iron compound, potassium compound, and magnesium compound as major components, as a dehydrogenating catalyst for producing diisopropyl isopropenyl benzene, isopropyl diisopropenyl benzene and/or triisopropenyl benzene from triisopropyl benzene. In the dehydrogenation of triisopropyl benzene or diisopropyl benzene, by carrying out an off-and-on reaction in which the above described solid catalyst is employed and with which a regeneration period with steam or oxygen or air is provided, an economical and industrial dehydrogenation method having an extended life of the catalyst can be provided and will have an industrial superiority.

Abstract: The present invention relates to a method for catalytic dehydrogenation of alkylaromatic hydrocarbons and more particularly, to a method for catalytic dehydrogenation of alkylaromatic hydrocarbons using carbon dioxide as a soft oxidant in the presence of a heterogeneous catalyst comprising both vanadium and iron, which allows operation at a lower reaction temperature due to improved thermodynamic equilibrium and provides an enhanced conversion of hydrocarbons and energy saving.

Abstract: A catalyst which is based upon an iron oxide and a compound of a lanthanide, of which iron oxide at least a portion is made by a process which involves heat decomposition of an iron halide, the lanthanide being in a quantity in the range of from 0.07 to 0.15 mole per mole iron oxide present in the catalyst, calculated as Fe2O3; a process for the preparation of the catalyst; a process for the dehydrogenation of an alkylaromatic compound which process involves contacting a feed containing the alkylaromatic compound with the catalyst; and a method of using an alkenylaromatic compound for making polymers or copolymers, in which method the alkenylaromatic compound has been prepared by the dehydrogenation process.

Abstract: A process for dehydrogenating organic compounds, in particular paraffins and naphthenes, is carried out in the presence of a supported catalyst comprising a group VIII metal such as platinum, and tin, at least a portion of which interacts strongly with the group VIII metal in the catalyst in the reduced state. In the partially oxidised state, the catalyst contains at least 10% of tin in the form of a reduced tin species with oxidation state 0, said species having an isomer shift in the range 0.80 to 2.60 mm/s and a quadrupolar splitting in the range 0.65 to 2.00 mm/s.

Abstract: This invention relates to a dehydrogenation process using a layered catalyst composition. The catalyst composition comprises an inner core such as alpha-alumina, and an outer layer bonded to the inner core composed of an outer refractory inorganic oxide such as gamma-alumina. The outer layer has uniformly dispersed thereon a platinum group metal such as platinum and a promoter metal such as tin. The composition also contains a modifier metal such as lithium. The catalyst composition shows improved durability and selectivity for dehydrogenating hydrocarbons, especially at dehydrogenation conditions comprising a low water concentration.

Abstract: The invention provides process and apparatus for conducting an endothermic reaction of an organic compound in the presence of molecular hydrogen and of multicomponent solids. The process comprises contacting the compound with a solid catalyst for the endothermic reaction and a hydrogen oxidizing solid reagent intermixed with the solid catalyst. Organic products of the endothermic reaction are produced, with evolution of molecular hydrogen. The solid catalyst becomes gradually deactivated by formation of carbonaceous deposits thereon. The evolved hydrogen undergoes an exothermic reaction with the hydrogen oxidizing solid reagent to form a reduction product which comprises deactivated hydrogen oxidizing solid reagent.

Abstract: The invention relates to a homogeneous bed of catalyst particles comprising at least one amorphous matrix, at least one noble metal, at least one additional metal M and at least one halogen, and in which, for a catalyst particle: CPt is the local concentration of noble metal; CM is the local concentration of additional metal M; Cx is the local concentration of halogen; in which catalyst particle bed the local dispersion of the value of CPt/CM or CPt/Cx is termed homogeneous along the diameter of the particle, which corresponds to at least 70% of the values CPt/CM or CPt/Cx deviating by a maximum of 30% from the local average ratio. The invention also relates to a process for transforming hydrocarbons into aromatic compounds with the catalyst, such as a gasoline reforming process and a process for producing aromatic compounds.

Abstract: A process of preparing a vinyl aromatic compound, such as styrene. The process involves fluidizing a dehydrogenation catalyst in a single shell fluidized bed reactor containing a reaction zone and a regeneration zone; contacting an alkyl aromatic compound, such as ethylbenzene, with the dehydrogenation catalyst in the dehydrogenation zone so as to produce the vinyl aromatic compound, such as styrene; and regenerating the catalyst in situ by contacting seam with the deactivated catalyst in the regeneration zone. A fluidized bed reactor is described, characterized by a freeboard zone, a reaction zone, and a catalyst regeneration zone, all within a single shell.

Abstract: A catalyst for the production of alkenylaromatics from alkylaromatics, wherein the catalyst is predominantly iron oxide, an alkali metal compound and a small amount of a source for palladium or platinum. Additional components of the catalyst may include compounds based on cerium, molybdenum, tungsten and other such promoters. Also a process for the production of alkenylaromatics from alkylaromatics using this catalyst.

Abstract: A process for the nonoxidative dehydrogenation of an alkylaromatic feed stream wherein the feed stream is passed through a radial reactor containing nonoxidative dehydrogenation catalysts, wherein the nonoxidative dehydrogenation catalysts are arranged in vertically layered beds within the radial reactor, and wherein the nonoxidative dehydrogenation catalysts include at least a first and a second nonoxidative dehydrogenation catalyst, wherein at least one of the nonoxidative dehydrogenation catalysts has a different performance and/or operating characteristic than at least one of the other nonoxidative dehydrogenation catalysts.

Abstract: Process for the catalytic dehydrogenation of ethylbenzene in which a feedstock containing ethylbenzene and steam is supplied into the inlet of a tubular reactor containing a dehydrogehation catalyst. Within the reactor, the feedstock flows through at least a portion of the reactor along a spiral flow path extending longitudinally of the reactor. The resulting styrene product is then recovered from a downstream or outlet section of the reactor. The spiral flow path through which the feedstock is passed is located at least adjacent the inlet side of the reactor and at least a portion of the spiral flow path contains a particulate dehydrogenation catalyst. The spiral flow path may extend throughout a major portion of the elongated tubular reactor and may contain a particulate dehydrogenation catalyst in a substantial portion there.

Abstract: Tetrahydroindene is dehydrogenated in a vapor phase in the presence of a metallic catalyst, e.g., a nickel-molybdenum catalyst, to produce indene, which is industrially useful in high yield while inhibiting the catalyst from suffering a decrease in activity. In particular, a higher yield can be attained by a method in which tetrahydroindene is dehydrogenated to first convert it into indane, which is further dehydrogenated to obtain indene.

Abstract: A mono-olefin hydrocarbon and/or a di-olefin hydrocarbon represented by the following general formula (3) is selectively produced by dehydrogenating or oxidative-dehydrogenating a mixture of any one of hydrocarbons among the hydrocarbons represented by the following general formula (1) and any one of hydrocarbons among the hydrocarbons represented by the following general formula (2), followed by distillation;

Abstract: A catalyst for the production of alkenylaromatics from alkylaromatics, wherein the catalyst is predominantly iron oxide, an alkali metal compound and a small amount of a source for palladium or platinum. Additional components of the catalyst may include compounds based on cerium, molybdenum, tungsten and other such promoters. Also a process for the production of alkenylaromatics from alkylaromatics using this catalyst.

Abstract: Catalytic system for dehydrogenating ethylbenzene to styrene, containing chromium oxide, tin oxide, at least one oxide of an alkaline metal (M) and an alumina carrier, in delta or theta phase or in a mixture of delta+theta or theta+alpha or delta+theta+alpha phases, modified with silica, and characterized in that: the chromium, expressed as Cr2O3, is in a quantity of between 6 and 30% by weight; the tin, expressed as SnO, is in a quantity of between 0.1 and 3.5% by weight; the alkaline metal, expressed as M2O, is in a quantity of between 0.4 and 3% by weight; the silica is in a quantity of between 0.08 and 3% by weight, the complement to 100 being alumina.

Abstract: A solid catalyst containing a potassium component and an iron oxide component, which is such that the ratio of the pore volume of pores therein having a diameter of from 20 to 100 nm to that of pores therein having a diameter of up to 100 nm falls between 0.7/1 and 0.9/1 and which is stable to oxygen-containing vapor, is favorably used as a dehydrogenation catalyst in producing vinyl-aromatic hydrocarbons from alkyl-aromatic hydrocarbons. The catalyst has high initial activity and good initial selectivity and its life is long. In addition, it is easy to handle. The catalyst may be produced by reducing a potassium component-containing iron oxide composition with hydrogen at a temperature falling between 350 and 600° C., and then oxidizing it with an oxygen molecules-containing vapor at a temperature falling between 250 and 500° C.

Abstract: A catalyst for the production of alkenylaromatics from alkylaromatics, wherein the catalyst is predominantly iron oxide, an alkali metal compound and a small amount of a source for palladium or platinum. Additional components of the catalyst may include compounds based on cerium, molybdenum, tungsten and other such promoters. Also a process for the production of alkenylaromatics from alkylaromatics using this catalyst.

Abstract: Catalysts in the form of cylindrical hollow granules, suitable for the dehydrogenation of ethylbenzene to styrene, and comprising, as active component, ferric oxide and promoters chosen among oxides of alkaline or alkaline-earth metals, oxides of elements of the lanthanide series, and chromium, tungsten, and molybdenum oxides, characterized by the absence of macroporosities with a radius of more than 50,000 .ANG. and/or by high mechanical characteristics of resistance to axial breaking and to abrasion.

Abstract: Process for the production of styrene which comprises:a) feeding to an alkylation unit a stream of benzene and a stream of recycled product containing ethylene;b) mixing the stream at the outlet of the alkylation unit, containing ethylbenzene, with a stream consisting of ethane;c) feeding the mixture thus obtained to a dehydrogenation unit containing a catalyst capable of contemporaneously dehydrogenating ethane and ethylbenzene;d) feeding the product leaving the dehydrogenation unit to a separation section to produce a stream essentially consisting of styrene and a stream containing ethylene;e) recycling the stream containing ethylene to the alkylation unit.

Abstract: Dehydrogenation catalysts are prepared by a predoping process comprising, mixing iron oxide materials with a predopant to form a blend of iron oxide and predopant and heating the blend to the predoping conditions and thereafter forming a catalyst. The catalysts so prepared are useful in the dehydrogenation of a composition having at least one carbon--carbon double bond. Such catalytic uses include the conversion of ethylbenzene to styrene.

Abstract: In a process for preparing olefinically unsaturated compounds such as styrene by oxidative dehydrogenation of corresponding hydrocarbons using a previously oxidized oxygen transferer acting as catalyst in the absence of molecular oxygen and reoxidation of the oxygen transferer in at least two reactors, the dehydrogenation and regeneration takes place alternately in time in the two reactors and the reactors are connected to one another in terms of heat via heat exchangers and a common circuit for heat transfer medium.

Abstract: A continuous process for the dehydrogenation of a hydrocarbon and/or oxygenated hydrocarbon feed, comprising contacting the hydrocarbon and/or oxygenated hydrocarbon feed with a dehydrogenation catalyst at elevated temperature in a reaction zone characterized in that the catalyst is capable of retaining hydrogen and (a) is contacted with a feed to form a dehydrogenated product and hydrogen, at least some of the hydrogen formed being adsorbed by the catalyst and/or reacting therewith to reduce at least part of the catalyst; (b) the dehydrogenated product and any unadsorbed/unreacted hydrogen is removed from the reaction zone; (c) at least some of the adsorbed hydrogen is removed from the catalyst and/or at least some of the reduced catalyst is oxidized; and (d) reusing the catalyst from step (c) in step (a).

Abstract: Alkylaromatic hydrocarbons are dehydrogenated into alkenylaromatic hydrocarbons by contacting them in the absence of molecular oxygen with a supported catalyst of the redox type wherein the metal in the catalyst is at a valency such that it is not in its most reduced state, and the catalyst is regenerated before being contacted with fresh feed.

Abstract: Aliphatic feeds are converted to olefins and/or aromatics in a multi pressure reactor system. A high pressure first stage reactor generates much or all of the hydrogen needed to reduce catalyst coking in lower pressure downstream reactors. High pressure operation protects catalyst stability in the first reactor, while produced hydrogen helps protect downstream catalyst. Low pressure downstream operation improves yields.

Abstract: Solid superacid catalyst, for example sulfated zirconia, is used in the oxidative dehydrogenation of saturated or partially saturated hydrocarbons, for example the conversion of isobutane to isobutylene in the presence of an oxygen-containing oxidizing agent at reaction conditions typically including temperatures from 500 to 1,000 degrees Fahrenheit, superatmospheric pressures, and oxygen/alkane molar ratios from 0.2 to 20. Performance of a metal-oxide or metal-hydroxide oxidative dehydrogenation catalyst may be enhanced by pretreating a solid superacid or other catalyst containing metal oxides or hydroxides at a carbonizing temperature with an organic material, for example an oxygen-containing organic material, to form a carbonaceous layer on the surface thereof prior to use of the catalyst in oxidative dehydrogenation.

Abstract: A method for preparing a high-purity p-isobutylstyrene is here disclosed which comprises the first step of reacting o- and/or m-isobutylethylbenzene, if necessary, together with isobutylbenzene, in the presence of an acid catalyst in a liquid phase at a reaction temperature of -10.degree. to 600.degree. C. so that the production of sec-butylethylbenzene in butylethylbenzene may not exceed 20% by weight, in order to form a mixture of p-isobutylethylbenzene and sec-butylethylbenzene; and the second step of bringing the mixture of p-isobutylethylbenzene and sec-butylethylbenzene recovered from the first step into contact with a dehydrogenation metal catalyst containing at least one metal selected from the groups Ib, IIb, VIa, VIIa and VIII of the periodic table at a reaction temperature of 300.degree. to 650.degree. C. under a reaction pressure of 50 kg/cm.sup.2 or less in a gaseous phase.

Abstract: A catalyst comprising a preshaped porous support material having applied thereto in finely divided form an active compound chosen from at least one compound of vanadium, chromium, manganese, iron, cobalt, nickel, copper and zinc, and optionally a promoter chosen from at least an alkali or alkaline earth metal compound, method for the preparation thereof and use thereof in the dehydrogenation of hydrocarbons.

Abstract: The instant invention relates to an improved dehydrogenation catalyst made up of iron oxide and potassium oxide which has been prepared by combining an iron-containing compound made up of from about 10% to 100% by weight of a micaceous iron oxide and a potassium-containing compound to form a pellet, followed by calcination. The catalyst is particularly suited for the non-oxidative dehydrogenation in the presence of steam of ethylbenzene to styrene.

Abstract: A method for preparing .alpha.-(4-isobutylphenyl)propionic acid or its precursor is here disclosed which comprises a step A of forming p-isobutylstyrene from p-isobutylethylbenzene and a step B of forming .alpha.-(4-isobutylphenyl)propionaldehyde from p-isobutylstyrene or a step C of forming .alpha.-(4-isobutylphenyl)propionic acid or its alkyl ester from p-isobutylstyrene.Furthermore, a method for preparing said p-isobutylethylbenzene is also disclosed which comprises alkylating isobutylbenzene or 4-ethyltoluene with ethylene or propylene.

Abstract: Improved iron oxide catalysts for the dehydrogenation of ethylbenzene to styrene are made by forming a blend of chromium oxide and yellow iron hydrate and heating the blend to convert the yellow iron hydrate to red iron oxide prior to forming the catalyst.

Abstract: Catalyst activity life of an iron oxide-containing catalyst is extended by contacting such catalyst with a feedstream containing about 0.0001 to about 0.01 mole of oxygen per mole of feed in the substantial absence of an oxidation catalyst.

Abstract: Dehydrogenatable hydrocarbons may be subjected to a dehydrogenation reaction in which the hydrocarbons such as ethylbenzene are treated with a dehydrogenation catalyst comprising a modified iron catalyst in the presence of steam. The reaction mixture containing unconverted ethylbenzene, styrene, hydrogen and steam is then contacted with an oxidation catalyst in a second zone whereby hydrogen is selectively oxidized to the substantial exclusion of oxidation of the hydrocarbon. The selective oxidation catalyst which is employed will comprise a noble metal of Group VIII of the Periodic Table, a metal of Group IVA and, if so desired, a metal of Group IA or IIA composited on a porous inorganic support such as alumina.

Abstract: A process for the catalytic dehydrogenation of a dehydrogenatable C.sub.2 -plus feed hydrocarbon which comprises the steps of: (a) passing a feed stream comprising the C.sub.2 -plus feed hydrocarbon into a dehydrogenation zone and through at least one bed of dehydrogenation catalyst maintained at dehydrogenation conditions and producing a dehydrogenation zone effluent stream comprising hydrogen, the C.sub.2 -plus feed hydrocarbon and a C.sub.2 -plus product hydrocarbon; (b) forming an oxidation catalyst bed feed stream by admixing an oxygen-containing stream with the dehydrogenation zone effluent stream; (c) passing the oxidation catalyst bed feed stream through a bed of hydrogen selective oxidation catalyst maintained at selective oxidation conditions and producing an oxidation zone effluent stream having a reduced concentration of hydrogen; and (d) recovering the product hydrocarbon from the oxidation zone effluent stream without contacting the oxidation zone effluent stream with dehydrogenation catalyst.

Abstract: A dehydrogenation catalyst containing iron and promoted with potassium and cerium has been shown to have improved activity when a copper compound is added thereto as a component. The improvement in activity is obtained without substantially sacrificing selectivity.

Abstract: An improved dehydrocyclization process for the selective conversion of light hydrocarbons to aromatics is presented. The activity of a catalyst containing nonacidic L-zeolite is greatly enhanced by the addition of water, water precursors, or mixtures thereof to the reaction zone during the dehydrocyclization reaction. Addition of between 10 and 100 wt. ppm H.sub.2 O results in a higher product yield of aromatics with increased product octane.

Abstract: A novel catalytic composite comprising a platinum group metal component; a modifier metal component selected from the group consisting of a tin component, germanium component, rhenium component and mixtures thereof; an optional alkali or alkaline earth metal component or mixtures thereof, an optional halogen component, and an optional catalytic modifier component on a refractory oxide support having a nominal diameter of at least about 850 microns. The distribution of the platinum group metal component is such that the platinum group component is surface-impregnated where substantially all of the platinum group metal component is located at most within a 400 micron exterior layer of the support. The effective amount of the modifier metal component is uniformly dispersed throughout the refractory oxide support.

Abstract: Dehydrogenation catalyst compositions for alkylaromatics and dehydrogenation processes using such catalysts are provided. The catalyst compositions comprise a catalytically active iron compound, e.g., iron oxide; a potassium catalyst promoter, e.g., potassium carbonate; an optional chromium compound stabilizer, e.g., chromic oxide, and a catalyst modifier combination of calcium and bismuth compounds, e.g., calcium oxide and bismuth trioxide. Utilization of particular amounts of calcium and bismuth compounds in dehydrogenation catalyst compositions of this type will provide a catalyst especially suitable for promoting the selective dehydrogenation of para-ethyltoluene to form para-methylstyrene in improved yields or the selective dehydrogenation of ethylbenzene to form styrene in improved yields.

Abstract: The invention is an improved method and apparatus for recovering waste heat from a low temperature process stream by means of a vaporizable heat sink liquid, characterized by an effective lowering of the boiling temperature of the heat sink liquid without need to reduce its boiling pressure. The heat sink liquid essentially comprises a mixture of two immiscible liquids that form a low boiling azeotrope. The heat sink liquid is brought into indirect heat exchange with the low temperature process stream for heat extraction. The invention involves simultaneous boiling of the two immiscible liquids to suppress the temperature of the heat sink liquid to below the low temperature of the process stream, whereby the heat sink liquid is able to recover heat from the process stream. In a preferred embodiment of the invention, the heat sink liquid comprises the reactants that are fed to a reactor, and the low temperature process stream is the reaction effluent from the reactor.