Abstract: A process for the regeneration of a zeolitic catalyst which is at least partially exhausted by use in the synthesis of optionally substituted methylenedianiline (MDA) and derivatives thereof, or of a mixture of optionally substituted MDA and derivatives thereof, with a higher homologous product the process involving washing said catalyst with an aromatic compound having at least one substitutent on the aromatic ring having activating characteristics with respect to the electrophilic substitution, in liquid or at least partially liquid phase.

Abstract: A method of cleaning the adsorbent media of a rotary concentrator in-situ while maintaining operation of the concentrator, including directing washing liquid into the sectors in the desorb plenum, then rotating the sectors one full revolution plus at least one sector into the desorb plenum to bring a second sector into the desorb plenum, washing the second sector and repeating the cycle until all of the adsorbent media is washed. The method may also include directing washing liquid into sectors not located in the desorb plenum.

Abstract: A process for regenerating a solid catalyst which has been used for producing propylene oxide through an epoxidation reaction of propylene with an organic peroxide in a reactor packed with the solid catalyst, which comprises allowing a liquid to flow through the catalyst packed in the reactor at a temperature not lower than the maximum reaction temperature of the epoxidation reaction. According to the present invention, a catalyst can be regenerated with extremely high efficiency without taking the catalyst to be regenerated out of the reactor.

Abstract: Methods and apparatus for removing a catalyst from a reaction mixture formed by reacting a hydrocarbon or an oxygenated hydrocarbon with an oxidant in the presence of the catalyst in a reactor, in which the reaction mixture contains one or more dibasic acids. The catalyst is removed by adding water and/or cooling the reaction mixture to cause phase separation, recycling the polar phase to the reactor, and transferring the less-polar phase to an ion exchange unit to remove catalyst contained therein.

Abstract: The invention relates to a process for decoating a used washcoat carrier substrate to produce a clean, inert carrier or substrate. In a preferred embodiment, a process according to the invention includes treating a washcoat catalyst substrate in an aqueous solution including an emulsifier. The substrate is also subject to ultrasonic treatment, while treating the substrate in an aqueous solution preferably including a dispersant. The substrate is ultimately rinsed, for example in deionized water. During treatment with the emulsifier, the solution can be agitated, for example by air injection. Likewise, during the ultrasonic treatment the solution can be agitated mechanically. Optional embodiments include the addition of an alkali to the emulsifier solution; rinsing between steps, for example with DI water; treatment with acid to remove sodium before final rinsing, final rinsing in a cascade system, and drying.

Abstract: The invention is directed to a method of stabilizing metalloaluminophosphate molecular sieves and catalysts derived therefrom. In particular, the invention is directed to a method of treating such molecular sieves with one or more nitrogen containing compounds having a kinetic diameter greater than the average pore size of the activated molecular sieve and selected from the group consisting of amines, monocyclic heterocyclic compounds, organonitrile compounds and mixtures thereof to chemisorbed and/or physisorbed the compound onto the molecular sieve. The compounds may be easily desorbed before or during use and after storage. The invention is also directed to formulating the molecular sieve into a catalyst useful in a process for producing olefin(s), preferably ethylene and/or propylene, from a feedstock, preferably an oxygenate containing feedstock.

Abstract: The present invention pertains to a process for activating a catalyst composition comprising at least one hydrogenation metal component of Group VI and/or Group VIII of the Periodic Table, and an S-containing organic additive, wherein the catalyst is contacted with hydrogen at a temperature between room temperature and about 600° C., preferably about 100-450° C., and prior to or during the contacting with hydrogen the catalyst is contacted with an organic liquid. Preferably, the contacting with the organic liquid is carried out prior to the contacting with hydrogen. The organic liquid may be a hydrocarbon with a boiling range of 150-500° C., preferably white oil, gasoline, diesel, or gas oil or mineral lube oil. It was found that the application of an organic liquid prior to or during the hydrogen treatment results in catalysts with an increased activity. The invention also comprises catalyst made by the above process and the use of such catalyst in hydrotreating.

Abstract: The invention relates to a process for selectively separating iron from other metal ions, in particular ions present in certain oxidation catalysts. It also relates to a process for recycling catalysts in the reaction for the oxidation of alcohols and/or ketones to carboxylic acids and more particularly the oxidation of cyclic alcohols and/or cyclic ketones to dicarboxylic acids, such as the oxidation of cyclohexanol and/or cyclohexanone to adipic acid. This process consists in treating the solution comprising the oxidation catalyst, before it is recycled, with an ion-exchange resin which makes it possible to selectively separate the iron from the other metal elements, in particular from copper and from vanadium.

Abstract: The present invention provides a process and its utilization in a process comprising the step of carrying out an addition reaction of an alkylene oxide to an addition-receiving substance in the presence of a resin catalyst, thereby producing the addition reaction product, when the resin catalyst as used for the reaction is persevered so as to recycle it after it is recovered, the unreacted alkylene oxide remaining in the resin catalyst can be prevented from polymerizing and solidifying during the preservation, and the resin catalyst accordingly can be preserved stably for a long time. The resin catalyst as recovered after it is used for the reaction may be preserved under any of the following conditions: 1) at a low temperature of not higher than 40° C.

Abstract: A batch process for carrying out a hydrogenation reaction comprises mixing a pyrophoric catalyst with reactants and solvents to form a reaction mixture in a reaction vessel. Hydrogen is added to the reaction vessel. After hydrogenation, the desired hydrogenation product is removed from the reaction vessel and the pyrophoric catalyst-rich material from the reaction vessel is delivered to a pressure filter. Water is added to the pyrophoric catalyst-rich material in the filter and the spent pyrophoric material is removed from the pressure filter in a water wet form.

Abstract: Disclosed are a catalyst for selective catalytic reduction of nitrogen oxides and a method for preparing the same. Useful for the removal of nitrogen oxides is a catalyst prepared using spent catalysts having been absorbed with vanadium, nickel and sulfur in the hydro-desulfurization line of an oil refinery in which a catalyst for the hydro-desulfurization contains molybdenum, iron, cobalt and silicon on the alumina support in accordance with the present invention. The present catalyst can remove nitrogen oxides at a level of 90% or higher, exhibiting a 10% or more increase in efficiency of the catalyst performance. Additionally, the catalyst can increase the efficiency of spent catalyst reclamation by 250%.

Abstract: The present invention relates to the effective utilization of a used catalyst containing at least molybdenum, an A element (at least one element selected from the group consisting of phosphorus and arsenic) and an X element (at least one element selected from the group consisting of potassium, rubidium and cesium), and provides a process for producing a catalyst, which comprises dispersing said used catalyst in water, adding thereto an alkali metal compound and/or ammonia solution, adjusting the resulting mixture to pH 6.5 or less to generate a precipitate containing at least molybdenum and the A element, and using the precipitate as a material for catalyst-constituting elements.

Abstract: The invention is directed to a method of stabilizing metalloaluminophosphate molecular sieves and catalysts derived therefrom. In particular, the invention is directed to a method of treating such molecular sieves with one or more nitrogen containing compounds selected from the group consisting of amines, monocyclic heterocyclic compounds, organonitrile compounds and mixtures thereof to chemisorbed and/or physisorbed the compound onto the molecular sieve. The compounds may be easily desorbed before or during use and after storage. The invention is also directed to formulating the molecular sieve into a catalyst useful in a process for producing olefin(s), preferably ethylene and/or propylene, from a feedstock, preferably an oxygenate containing feedstock.

Abstract: A process for regenerating a zeolite catalyst comprises the following stages: (I) Heating a partially or completely deactivated catalyst to 250-600° C. in an atmosphere which contains less than 2% by volume of oxygen, (II) treating the catalyst at from 250 to 800° C., preferably from 350 to 600° C., with a gas stream which contains from 0.1 to 4% by volume of an oxygen-donating substance or of oxygen or of a mixture of two or more thereof, and (III) treating the catalyst at from 250 to 800° C., preferably from 350 to 600° C., with a gas stream which contains from more than 4 to 100% by volume of an oxygen-donating substance or of oxygen or of a mixture of two or more thereof.

Abstract: The present invention aims at inhibiting a lowering in the modification ratio of a modified cation-exchange resin, in which part of the sulfonic acid groups have been modified with a thiol-containing amine compound and which is employed as a catalyst for producing bisphenol, during preservation. In the present invention, a modified cation-exchange resin is packed together with water into a container while regulating the surface area of the container to 0.5 m2 or less per liter of the resin and then the container is sealed up so that the resin is preserved in a state of being soaked in water.

Abstract: The invention relates to a method for separating and recovering rhodium from reaction products of oxosynthesis, especially reaction products containing cobalt. The invention also relates to the reuse of rhodium as a catalyst for hydroformulation and to a catalyst for hydroformulation itself. The inventive method is characterized by the following: extraction of the organic solution with an aqueous phosphate solution or a phosphate solution, water washing, oxidative treatment of the organic phase, and extraction of the organic phase with an aqueous water-soluble arylphosphine solution.

Abstract: Methods and systems for regenerating and pretreating oxides of manganese and precipitation of oxides of manganese from manganese salt solutions. The oxides of manganese and manganese salt solutions are processed utilizing heated aqueous oxidizing solutions at or near boiling at atmospheric pressure. Solution temperature, Eh value and pH value are monitored and adjusted so as to move solution conditions into and to maintain them within the MnO2 stability area. This results in regenerated, pretreated and precipitated oxides of manganese having high or increased pollutant loading capacities and/or oxidation states. Oxides of manganese thus produced are, amongst other uses; suitable for use as a sorbent for capturing or removing target pollutants from industrial gas streams. Filtrate process streams containing useful and recoverable value present as spectator ions may be further processed to produce useful and marketable by-products.

Abstract: A method for regenerating an amine extractant used for recovery of metals involves contacting a liquid organic phase containing an amine complexed with one or more metals with an aqueous solution substantially free of chloride ions to strip the one or more metals from the organic phase. The stripped organic phase is then contacted with a solution of hydrochloric acid to regenerate the amine extractant which can then be recycled in a production process.

Abstract: A catalyst active in ammonia synthesis with improved activity and a process for the recovery of useful components from the catalyst.

Abstract: A method for regenerating spent supported metal catalysts comprising treating the spent catalyst with an organo-metallic complex forming agent having an ionization constant pK1 of at least 2.5. The catalyst activity is restored to an activity level near to or greater than the fresh catalyst. The regeneration method is particularly useful for regenerating spent palladium catalysts on an alumina support as utilized for the hydrogenation of ethyl anthraquinone (EAQ) in the production of hydrogen peroxide.

Abstract: Methods for removing soluble material from confined spaces within substrates such as containers, capsules and porous powders comprising extraction with supercritical fluids, the pressure of which is preferably modulated between an upper level and a lower level within a relatively narrow range of fluid pressure and density. The method permits enhanced extraction efficiency, catalytic reaction rates and ability to maintain catalyst activity.

Abstract: A substantially water-free hydrocarbon feed is charged to a reformer reactor operated under reforming conditions; thereafter, a chlorine-containing additive is introduced, without the simultaneous introduction of water, into the substantially water-free hydrocarbon feed being charged to the reformer reactor in an amount and for a time period that are effective to inhibit deactivation of the reformer catalyst; thereafter, the introduction of the chlorine-containing additive is terminated and the charging of the substantially water-free hydrocarbon feed to the reformer reactor is continued.

Abstract: Catalysts made from a newly discovered phase of aluminum trihydroxide and processes for making such catalysts. This invention also relates to a method for improving the activity of and for regenerating catalysts having a silica-alumina support.

Abstract: The invention relates to a method for separating and recovering rhodium from reaction products of oxosynthesis, especially reaction products containing cobalt. The invention also relates to the reuse of rhodium as a catalyst for hydroformulation and to a catalyst for hydroformulation itself. The inventive method is characterized by the following: extraction of the organic solution with an aqueous phosphate solution or a phosphate solution, water washing, oxidative treatment of the organic phase, and extraction of the organic phase with an aqueous water-soluble arylphosphine solution.

Abstract: A process for the separation a substantially adduct-free diaryl carbonate from reaction solution is disclosed. The process entails obtaining a solution that contains diaryl carbonate, catalyst system components and an aromatic solvent, lowering the temperature of the solution, optionally in the presence of a nucleating agent, to produce a crystallization product, and washing the crystallization product with an anhydrous wash solution to remove catalyst residues and impurities.

Abstract: While a substantially water-free hydrocarbon feed is being charged to a catalytic reformer reactor, an organic chloride is contacted with the reformer catalyst in an amount and for a time period that are effective to restore at least a portion of the activity of the reformer catalyst.

Abstract: A method for regeneration of a molybdenum-containing oxide fluidized bed catalyst which comprises impregnating a fluidized catalyst of a metal oxide containing molybdenum, bismuth and iron which has been deteriorated by being used for a reaction in production of acrylonitrile by ammoxidation of propylene, with a solution of a molybdenum compound and a solution of at least one compound containing at least one element selected from the group consisting of iron, chromium, lanthanum and cerium which are prepared separately or with a previously prepared mixed solution of the above compounds, drying the resulting catalyst and, then, firing the catalyst at a temperature of 500-700° C.

Abstract: A method for separating an oxidation catalyst, an oxidation reaction product and a reaction solvent from a reaction mixture obtained by oxidizing a substrate in the presence of an oxidation catalyst containing an aromatic N-hydroxyimide compound and a transition metal, the method including (i) distilling the reaction solvent from the reaction mixture in the presence of an organic solvent which is immiscible with the reaction solvent to obtain the reaction mixture containing the reaction solvent in an amount of 5 parts by weight or less per one part by weight of the N-hydroxyimide compound, and the oxidation catalyst precipitated, and (ii) separating the reaction mixture obtained in the step (i) by a solid-liquid separation method into the oxidation product and the oxidation catalyst.

Abstract: A process for treating an exhaust gas from a lean-burn internal combustion engine containing sulfur, oxides (SOx) and at least one other atmospheric pollutant selected from HC, CO, NO and soot, which gas being untreated or having undergone some chemical and/or catalytic treatment, comprises the steps of absorbing a sulfate-forming SOx component in a solid absorbent material, passing gas containing SO2 to atmosphere and periodically replacing the absorbent material. A system for carrying out the process comprises exhaust passage and a sulfate absorber (26) comprising a substrate supporting a solid material for absorbing a sulfate-forming component from SOx in the exhaust gas, which sulfate absorber is adapted to be replaceable.

Abstract: A process for increasing the hydrogenation activity, particularly the carbon monoxide hydrogenation activity, of a catalyst or catalyst precursor comprised of a particulate solids support component and a catalytic metal, or metals component, preferably cobalt; cobalt alone or cobalt and an additional metal, or metals added to promote or modify the reaction produced by the cobalt. Treatment of the catalyst, or catalyst precursor is conducted at low temperature ranging from ambient to about 275° C. sufficient to form on the surface of a catalyst precursor, e.g., a cobalt catalyst precursor, a cobalt metal hydroxide, low valence cobalt metal oxide, or mixture of cobalt metal hydroxide and low valence cobalt metal oxide. Sometimes also metallic metal, e.g., cobalt, is also formed, and dispersed on the surface of the support.

Abstract: Novel polymer-supported quenching reagents of Formula I, P—L—Q  I wherein P is a polymer of low chemical reactivity which is soluble or insoluble; Q is one or more quenching reagents, or an acid or base addition salts thereof, that are capable of selective covalent reaction with unwanted byproducts, or excess reagents; and L is one or more chemically robust linkers that join P and Q; are described, as well as methods for their preparation and methods for their use in the rapid purification of synthetic intermediates and products in organic synthesis, combinatorial chemistry and automated organic synthesis.

Abstract: This invention is to a method of rejuvenating a molecular sieve. The method includes contacting a molecular sieve having a methanol uptake index of less than 1, or a catalyst containing molecular sieve having a methanol uptake index of less than 1, with anhydrous liquid or vapor until the methanol uptake index is increased by at least 10%. The rejuvenated molecular sieve or catalyst can be used to make an olefin product from an oxygenate-containing feedstock. The preferred molecular sieve is a silicoaluminophosphate (SAPO) molecular sieve.

Abstract: Used deNOx or dedioxin catalytic converters are regenerated by washing the catalyst with a solution of surface-active substances in a liquid. At the same time, metal compounds are added for creating active centers.

Abstract: Deactivation of a reformer catalyst is inhibited by charging a hydrocarbon feed having a concentration of an organic aluminum halide compound to a reformer reactor operating under reforming conditions and containing a reformer catalyst.

Abstract: An aqueous low temperature oxidation (ALTO) process wherein a catalyst or catalyst precursor constituted of a solids support, or powder component, and a metal, or metals component, inclusive of cobalt, is oxidized, reduced and rendered catalytically active for conducting carbon monoxide hydrogenation reactions. The cobalt catalyst or cobalt catalyst precursor is thus contacted at low temperature with an oxidant in the presence of water (e.g., water to which an oxidant is added), sufficient to oxidize the cobalt metal, or metals component of the catalyst or catalyst precursor. On reduction, the hydrogenation activity of the cobalt catalyst is increased. All or a portion of the cobalt metal of the catalyst precursor is oxidized to form a Co2+ cationic or oxo-anionic species at least during the initial phase of the reaction.

Abstract: A substantially water-free hydrocarbon feed is charged to a multiple-reactor reformer system being operated under reforming conditions and comprising at least two reformer reactors serially connected in fluid-flow communication and each containing a reformer catalyst; and, simultaneously with the charging step, a chloriding agent is sequentially introduced, without simultaneously introducing water, immediately upstream from the inlets of all the reformer reactors in an amount and for a period of time that are effective to inhibit the deactivation of the reformer catalyst.

Abstract: This invention relates to a method for regenerating a cyclic olefin hydration catalyst, in which a solid acid catalyst is regenerated after its use in a hydration reaction of a cyclic olefin by mixing a water phase containing the solid acid catalyst and an oil phase containing the cyclic olefin and thereby effecting the reaction, which comprises separating the reaction solution into oil phase and water phase at a temperature of 40° C. or more and subsequently subjecting at least a portion of the solid acid catalyst in the separated water phase to a regeneration treatment. According to the method of this invention, a catalyst used in the hydration of a cyclic olefin can be separated and regenerated efficiently, and it is a particularly suitable catalyst regeneration method for a case in which hydration of a cyclic olefin is carried out for a prolonged period of time by repeating regeneration and use of the catalyst again and again.

Abstract: A process is described for regenerating exhausted zeolitic catalysts containing titanium and deriving from oxidation processes of organic substrates with hydrogen peroxide. Said process consists in carrying out a treatment in an aqueous medium with hydrogen peroxide in the presence of inorganic fluorinated compounds, subsequent to thermal treatment of the exhausted catalyst.

Abstract: This invention relates to a process for reactivating a dehydrocyclodimerization catalyst. Dehydrocyclodimerization catalysts which contain an aluminum phosphate binder can be deactivated when they are exposed to hydrogen at temperatures above 500° C. The instant process restores substantially all of the catalyst's lost activity. The process involves treating the catalyst with a fluid comprising water and drying the catalyst. The process is employed particularly advantageously in combination with coke removal for reactivating catalysts that contain coke deposits and that have also been hydrogen deactivated. This invention also relates to a method of producing a dehydrocyclodimerization catalyst that is resistant to hydrogen deactivation.

Abstract: The invention relates to a method for renewed activation of honeycomb-shaped catalyst elements for denitrating flue gases from fossil fuel-fired boiler plants, specially coal-fired boiler plants in large power stations. According to the invention, each catalyst element if mechanically cleaned using oil and water-free compressed air before mounting. Subsequently, each element is subjected to wet chemical cleaning using fully desalinated water and dried with oil and water-free compressed air. The inventive method enables the activity of used catalyst elements to be increased from less than 50% to more than 83% of original activity.

Abstract: A process for regenerating a zeolite catalyst comprises the following stages: (I) Heating a partially or completely deactivated catalyst to 250-600° C. in an atmosphere which contains less than 2% by volume of oxygen, (II) treating the catalyst at from 250 to 800° C., preferably from 350 to 600° C., with a gas stream which contains from 0.1 to 4% by volume of an oxygen-donating substance or of oxygen or of a mixture of two or more thereof, and (III) treating the catalyst at from 250 to 800° C., preferably from 350 to 600° C., with a gas stream which contains from more than 4 to 100% by volume of an oxygen-donating substance or of oxygen or of a mixture of two or more thereof.

Abstract: Methods and apparatus for removing a catalyst from a reaction mixture formed by reacting a hydrocarbon and an oxidant in the presence of the catalyst in a reactor, in which the reaction mixture contains one or more dibasic acids. The catalyst is removed by adding water and/or cooling the reaction mixture to cause phase separation, recycling the polar phase to the reactor, and transferring the non-polar phase to an ion exchange unit to remove catalyst contained therein.

Abstract: A process and catalyst for the partial oxidation of paraffinic hydrocarbons, such as ethane, propane, naphtha, and natural gas condensates, to olefins, such as ethylene and propylene. The process involves contacting a paraffinic hydrocarbon with oxygen in the presence of a catalyst under autothermal process conditions. The catalyst comprises a Group 8B metal and, optionally, a promoter metal, such as tin or copper, supported on a fiber monolith support, preferably a ceramic fiber mat monolith. In another aspect, the invention is a process of oxidizing a paraffinic hydrocarbon to an olefin under autothermal conditions in the presence of a catalyst comprising a Group 8B metal and, optionally, a promoter metal, the metals being loaded onto the front face of a monolith support. An on-line method of synthesizing and regenerating catalysts for autothermal oxidation processes is also disclosed.

Abstract: The present invention provides a process for regenerating a spent aromatics alkylation or transalkylation catalyst comprising a molecular sieve by contacting the spent catalyst with an oxygen-containing gas at a temperature of about 120 to about 600° C. and then contacting the catalyst with an aqueous medium, such as an ammonium nitrate solution, an ammonium carbonate solution or an acetic acid solution.

Abstract: A process for regenerating spent zeolite composites. The process involves contacting the composite, either as a shaped article or a fine powder, with a caustic solution, e.g., sodium hydroxide at treating condition. Once the contacting is completed, the composite is isolated, washed with water, dried and calcined to give a regenerated composite.

Abstract: A novel process for the regeneration of a solid adsorbent which is at least partially spent and has a reactive metal (e.g. silver) dispersed thereon is disclosed. The regeneration consists of a step whereby accumulated metal-containing reaction products formed during adsorptive service are removed by stripping the spent or partially spent adsorbent with a suitable stripping solution such as sodium thiosulfate. After detrimental metal-containing deposits are stripped, the adsorbent is then subjected to a reactivation step in which the regenerated adsorbent is contacted with a solution containing a reactive metal compound (e.g. silver nitrate). Reactivating the adsorbent therefore adds an incremental amount of the reactive metal onto the adsorbent. Regeneration of the adsorbent according to the two-step method of the present invention thus effectively prolongs its useful life.

Abstract: A cleaning kit for removing process impurities carried on the surface of a NOX reduction catalyst which is installed in the path of a flue gas flow exiting from a fossil fuel burning facility including: a reagent supply grill; a source of supply of liquid cleaning reagent; a reagent collection basin; and a recirculating structure. The reagent supply grid is adapted to be selectively positioned above a portion of a catalyst layer. The source of supply of liquid cleaning reagent adapted to be in communication with the supply grid, and the reagent collection basin being adapted to be selectively positioned below the portion of such catalyst layer to catch cleaning reagent therein after such reagent passes through such portion of the catalyst layer. the recirculating structure recirculates at least a portion of such reagent from the collecting basin for recirculating through such supply grid for further cleaning of such portion of the catalyst layer.

Abstract: The monosodium and monopotassium citrates are improved iron-sequestering agents in salt compositions for regenerating spent water softener cation exchange resins. The dry compositions comprise a surfactant, an alkali metal chloride selected from the group consisting of sodium chloride and potassium chloride, and an iron sequestering agent selected from the group consisting of monosodium citrate and monopotassium citrate. The composition is preferably provided in the form of compacted pellets or blocks. The method for regenerating the spent cation exchange resin bed comprises the step of contacting the resin bed with an aqueous brine solution containing the citrate and a surfactant and having a pH of about 3.5 to 4.5.

Abstract: Methods for removing soluble material from confined spaces within substrates such as containers, capsules and porous powders comprising extraction with supercritical fluids, the pressure of which is preferably modulated between an upper level and a lower level within a relatively narrow range of fluid pressure and density. The method permits enhanced extraction efficiency, catalytic reaction rates and ability to maintain catalyst activity.

Abstract: A process for the desulfurization, and reactivation of a sulfur deactivated catalyst constituted of cobalt composited with a titania support. The sulfur deactivated cobalt titania catalyst is first contacted with a gaseous stream of molecular oxygen at temperature sufficiently high to oxidize the sulfur component of the catalyst. The sulfur oxidized catalyst is next contacted with a liquid, preferably water, to remove the oxide, or oxides of the sulfur. The catalyst is then contacted with a reducing agent, suitably hydrogen, to restore the activity of the catalyst. During the treatment there is no substantial loss, if any, of cobalt from the catalyst.