Abstract: In a process for the synthesis of a nitrile by endothermic catalyzed reaction of ammonia with a hydrocarbon using heating obtained by passing an alternating current through a metallic coil, the endothermic reaction between ammonia and the hydrocarbon takes place in a reactor with direct inductive heating in the reaction zone. The heating is extremely fast, which makes the reaction practically instantaneous.

Abstract: Disclosed is a process for co-manufacture of ACRN and HCN with improved HCN selectivity and reduced solids formation in a shared product recovery section.

Abstract: This disclosure provides a facial green method for metal cyanides preparation, including the following steps: 1) supported metal nanoparticles and Fenton's reagent are mixed with nitrile and then stirred to obtain suspension, wherein metal nanoparticles are selected from a nano metal, nano metal oxide and nano metal salt; 2) centrifuging the suspension to obtain a product and drying the product after stirring to obtain the metal cyanides. As prepared metal cyanides have broad application prospects in the fields of sensor, battery, medicine, electroplating and catalysis. This Fenton-improved cyanation (FIC) method may effectively exclude the toxicity from free cyanide anions and get rid of UV-light, being more energy-saving and more feasible for large-scale industrial production of MCs.

Abstract: A method for providing 11C-labeled cyanides from 11C labeled oxides in a target gas stream retrieved from an irradiated high pressure gaseous target containing O2 is provided, wherein 11C labeled oxides are reduced with H2 in the presence of a nickel catalyst under a pressure and a temperature sufficient to form a product stream comprising at least about 95% 11CH4 , the 11CH4 is then combined with an excess of NH3 in a carrier/reaction stream flowing at an accelerated velocity and the combined 11CH4 carrier/reaction stream is then contacted with a platinum (Pt) catalyst particulate supported on a substantially-chemically-nonreactive heat-stable support at a temperature of at least about 900 ° C., whereby a product stream comprising at least about 60%H11CN is provided in less than 10 minutes from retrieval of the 11C labeled oxide.

Abstract: The invention includes an apparatus and process for the catalytic production of HCN from a feed gas of ammonia and a hydrocarbon gas by means of heat tubes supplying heat to the feed gas stream and heat tubes for removal of heat from the products. The invention further includes a process for N2O abatement comprising transferring heat from an exothermic N2O degradation reaction through a heat pipe.

Abstract: The present invention relates to an improved process for producing hydrocyanic acid by reaction of ammonia with methane in which a small amount of at least one sulphur-containing compound corresponding to the general formula R S (S)x—R? is added, in which R and R?, which are identical or different, represent a linear or branched alkyl or alkenyl radical containing from 1 to 5 carbon atoms, and x is a number ranging from 1 to 5, to the reactive gas mixture before it passes over the catalyst. The process according to the invention makes it possible to obtain improved yields of HCN. Another subject of the invention relates to the use of the resulting product for producing methionine, acetone cyanohydrin, adiponitrile or sodium cyanide.

Abstract: Provided is a method of remediating cyanide-contaminated soil. The method is provided to remediate soil contaminated with cyanide and treat the cyanide, which includes collecting the soil contaminated with first cyanide in a solid state and second cyanide in a gaseous or dissolved state, dissociating cyanide by mixing the soil with an alkali washing solution, dissolving the first cyanide in a solid state in the washing solution, and transferring the second cyanide in a dissolved state dissociated from the soil to the washing solution, dissociating the soil from the washing solution, precipitating the first cyanide in a solid state by acidifying the washing solution containing the cyanide, and performing post-treatment on the first cyanide after the first cyanide precipitated in a solid state is dissociated from the washing solution.

Abstract: A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

Abstract: A metal fiber based on one or several elements from the group of platinum, palladium, rhodium, ruthenium, and iridium with 0 to 30% by weight of one or several additional alloy elements from the group of nickel, cobalt, gold, rhenium, molybdenum, and tungsten, contains 1 to 500 ppm by weight of boron or phosphorus. A non-woven material or netting, in particular for the production of nitrogen oxide or for the production of hydrocyanic acid, is made of such fibers. For the production of fibers based on noble metals having up to 30% by weight of additional alloy metals by drawing the fibers from a melt, the melting point of the metal is reduced by at least 400 ° C., before drawing of the fibers, by additionally alloying with boron or phosphorus, and the boron or the phosphorus is removed again from the fibers.

Abstract: A metal fiber based on one or several elements from the group of platinum, palladium, rhodium, ruthenium, and iridium with 0 to 30% by weight of one or several additional alloy elements from the group of nickel, cobalt, gold, rhenium, molybdenum, and tungsten, contains 1 to 500 ppm by weight of boron or phosphorus. A non-woven material or netting, in particular for the production of nitrogen oxide or for the production of hydrocyanic acid, is made of such fibers. For the production of fibers based on noble metals having up to 30% by weight of additional alloy metals by drawing the fibers from a melt, the melting point of the metal is reduced by at least 400° C., before drawing of the fibers, by additionally alloying with boron or phosphorus, and the boron or the phosphorus is removed again from the fibers.

Abstract: A process (10) for at least partially removing hydrogen cyanide from synthesis gas includes feeding a synthesis gas (30) containing hydrogen cyanide to a gas-liquid contacting stage (18) and, in the gas-liquid contacting stage (18), contacting the synthesis gas with an aqueous washing solution (36) comprising at least one dissolved metal salt, with metal cations of the metal salt being capable of forming metal cyanide complexes and/or metal cyanide precipitates, and weak acid anions of the metal salt serving to buffer the pH of the washing solution in a range between 6 and 10. Hydrogen cyanide is washed from the synthesis gas by the washing solution to form a treated synthesis gas (38) and a spent washing solution (40). From time to time or continuously, at least a portion of the spent washing solution is withdrawn from the gas-liquid contacting stage. The treated synthesis gas (38) is also withdrawn from the gas-liquid contacting stage.

Abstract: The present invention relates to electrolytes comprising tetracyanoborate and an organic cation as components of electrolytes in electrochemical and/or optoelectronic devices, in particular solar cells. This ionic liquid has low viscosity and can be used as electrolyte in the absence of a solvent. Importantly, the ionic liquid remains stable in solar cells even after prolonged thermal stress at 80° C. for 1000 hours. Photovoltaic conversion efficiency remained stable and keeping more than 90% of the initial value.

Abstract: The present invention provides a process for producing a nitrogen-containing carbon material, comprising a first step of subjecting azulmic acid to a first heat treatment in an oxygen-containing gas atmosphere, thereby preparing a heat-treated product, and a second step of subjecting the heat-treated product to a second heat treatment in an inert gas atmosphere.

Abstract: The present invention relates to solutions comprising water and at least one metal cyanide, at least a part of the water being obtained from wastewater which occurs as depleted wastewater in a process for extracting noble metals from noble metal-containing ores by the cyanide process, the process for the preparation of solutions according to the invention and to the use of the solutions according to the invention in a process for extracting noble metals from noble metal-containing ores by the cyanide process, to a process for extracting noble metals from noble metal-containing ores by the cyanide process, wherein the solution according to the invention is used, and to the use of depleted wastewater occurring in the extraction of noble metals from noble metal-containing ores by the cyanide process to the preparation of solutions comprising water and at least one metal cyanide.

Abstract: A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

Abstract: The invention relates to a hydrocyanic acid containing bioresource carbon, and to a method for producing a raw material mainly containing the same by reacting ammonia with methane or methanol optionally in the presence of air and/or oxygen, characterized in that at least one of the reagents selected from ammonia, methane and methanol is obtained from a biomass. The invention also relates to the uses of the raw material for producing acetone cyanohydrin, adiponitrile, methionine or methionine hydroxyl-analog, and sodium cyanide.

Abstract: A metal fiber based on one or several elements from the group of platinum, palladium, rhodium, ruthenium, and iridium with 0 to 30% by weight of one or several additional alloy elements from the group of nickel, cobalt, gold, rhenium, molybdenum, and tungsten, contains 1 to 500 ppm by weight of boron or phosphorus. A non-woven material or netting, in particular for the production of nitrogen oxide or for the production of hydrocyanic acid, is made of such fibers. For the production of fibers based on noble metals having up to 30% by weight of additional alloy metals by drawing the fibers from a melt, the melting point of the metal is reduced by at least 400 ° C., before drawing of the fibers, by additionally alloying with boron or phosphorus, and the boron or the phosphorus is removed again from the fibers.

Abstract: The present invention relates to an improved process for producing hydrocyanic acid by reaction of ammonia with methane in which a small amount of at least one sulphur-containing compound corresponding to the general formula R S (S)x—R? is added, in which R and R? which are identical or different, represent a linear or branched alkyl or alkenyl radical containing from 1 to 5 carbon atoms, and x is a number ranging from 1 to 5, to the reactive gas mixture before it passes over the catalyst. The process according to the invention makes it possible to obtain improved yields of HCN. Another subject of the invention relates to the use of the resulting product for producing methionine, acetone cyanohydrin, adiponitrile or sodium cyanide.

Abstract: The present invention provides a process for producing a nitrogen-containing carbon material, comprising a first step of subjecting azulmic acid to a first heat treatment in an oxygen-containing gas atmosphere, thereby preparing a heat-treated product, and a second step of subjecting the heat-treated product to a second heat treatment in an inert gas atmosphere.

Abstract: A process for dewatering hydrocyanic acid by distillation, which includes distilling crude hydrocyanic acid containing from 50 to 99.9% by weight of HCN, from 0.1 to 40% by weight of water, from 0 to 15% by weight of carbon oxides and optionally from 0.01 to 1% by weight of an involatile stabilizer, at a pressure of from 1 bar to 2.5 bar, a bottom temperature of from 100° C. to 130° C. and a top temperature of from 25° C. to 54° C., in the absence of a volatile stabilizer, in a distillation column to obtain a top draw stream containing purified, anhydrous hydrocyanic acid and carbon oxides and a bottom draw stream including water and, optionally, the involatile stabilizer.

Abstract: A process is described for preparing hydrogen cyanide by autothermal noncatalytic oxidation of one or more nitrogenous hydrocarbons or a nitrogenous hydrocarbon mixture in which the nitrogenous hydrocarbons, an oxygen-containing gas, with or without ammonia, with or without water, with or without a gas containing nitrogen oxides and with or without other essentially inert feed gas constituents are introduced into a flame reaction zone, react in the flame reaction zone and a post-reaction zone at a temperature of from 1000 to 1800° C. for a reaction time of 0.03 to 0.3 s to form a cleavage gas which comprises at least the constituents hydrogen cyanide, carbon oxides, hydrogen, water, ammonia, nitrogen, light hydrocarbons with or without other cleavage gas constituents, the atomic C/N ratio in the reaction zones being from 1 to 7 and the atomic air ratio ?ato being <0.6, the cleavage gas being cooled and separated.

Abstract: The present invention relates to a catalytic device for the implementation of a reaction in a gaseous medium at high temperature, such as, for example, the synthesis of HCN or the oxidation of ammonia, comprising: at least one textured material (1) which is effective as catalyst for the said reaction, a support (2) comprising at least one ceramic part (3), the structure of which makes possible the passage of the gases, the said part (3) of the said support (2) having a corrugated face (6), so that the increase in surface area (?) produced by the corrugations with respect to a flat surface is at least equal to that (?) calculated for sawtooth corrugations and of between approximately 1.1 and approximately 3, the said textured material (1) being positioned so that it is held against the corrugated face (6) of the said part (3) of the said support (2) and follows the form thereof.

Abstract: A conical reactor head for use in chemical processes or other systems is provided. The reactor head includes a robust internal insulator to boost efficiency while maintaining safety by allowing the reactor head to self-radiate at high temperatures. The reactor head also includes a plurality of support lugs to protect its bottom flange from scratches or other damage when the reactor head is set on the ground. The reactor head is adapted to connect to a catalyst-containing barrel which is specially designed to facilitate easy installation and removal of catalysts or other equipment from outside the barrel. The reactor may be coupled with a rotation vane to induce laminar flow at the inlet of the reactor to increase reactor efficiency and prolong catalyst life.

Abstract: A process for the enhanced recovery and operation of hydrogen cyanide (HCN)/heads column obtained from the reactor effluent of an ammoxidation reaction of propane, propylene or isobutylene by reducing the polymer formation above the feed tray in the heads tower.

Abstract: A conical reactor head for use in chemical processes or other systems is provided. The reactor head includes a robust internal insulator to boost efficiency while maintaining safety by allowing the reactor head to self-radiate at high temperatures. The reactor head also includes a plurality of support lugs to protect its bottom flange from scratches or other damage when the reactor head is set on the ground. The reactor head is adapted to connect to a catalyst-containing barrel which is specially designed to facilitate easy installation and removal of catalysts or other equipment from outside the barrel. The reactor may be coupled with a rotation vane to induce laminar flow at the inlet of the reactor to increase reactor efficiency and prolong catalyst life.

Abstract: A process and a device for reducing the nitrous oxide which is formed during the catalytic combustion of ammonia and oxygen to form nitrogen oxides. A catalyst system including at least one first catalyst mesh element and at least one second catalyst mesh element is used for the catalytic combustion of ammonia and oxygen to form nitrogen oxides, where the minimum of one first catalyst mesh element is a platinum-rhodium mesh and the minimum of one second, downstream catalyst mesh element is a palladium-rhodium mesh with 2-4 wt. % of rhodium.

Abstract: A conical reactor head for use in chemical processes or other systems is provided. The reactor head includes a robust internal insulator to boost efficiency while maintaining safety by allowing the reactor head to self-radiate at high temperatures. The reactor head also includes a plurality of support lugs to protect its bottom flange from scratches or other damage when the reactor head is set on the ground. The reactor head is adapted to connect to a catalyst-containing barrel which is specially designed to facilitate easy installation and removal of catalysts or other equipment from outside the barrel.

Abstract: A conical reactor head for use in chemical processes or other systems is provided. The reactor head includes a robust internal insulator to boost efficiency while maintaining safety by allowing the reactor head to self-radiate at high temperatures. The reactor head also includes a plurality of support lugs to protect its bottom flange from scratches or other damage when the reactor head is set on the ground. The reactor head is adapted to connect to a catalyst-containing barrel which is specially designed to facilitate easy installation and removal of catalysts or other equipment from outside the barrel.

Abstract: The invention provides a process for recovering hydrogen cyanide from an aqueous solution by extracting the hydrogen cyanide into an organic solvent phase. The organic solvent may comprise a neutral organophosphorous compounds, such as compounds selected from the group consisting of alkyl or aryl substituted phosphates, phosphonates and phosphine oxides. In alternative embodiments the organophosphorous compound is tri-butyl phosphate, di-butyl-butyl-phosphonate or tri-alkyl phosphine oxides. The organic solvent may be diluted in an organic diluent, such as an aliphatic or kerosene-type diluent. Alternative dilutions may be used, such as 75%, 50% or 25%. In some embodiments, the pH of the aqueous solution containing dissolved cyanide may be adjusted to between 2 and 8, or between 3 and 7, or between 4 and 6. The organic solvent may be contacted following extraction with a basic aqueous solution to strip cyanide from the organic solvent into a basic aqueous cyanide strip solution.

Abstract: According to this method for the adsorptive extraction of hydrocarbons from aqueous solutions of hydrocyanic acid, the initial solutions containing 1 to 50 wt. % hydrocyanic acid and 2 to 1000 wt. ppm aliphatic and/or aromatic hydrocarbons, the latter having 6 to 30 C atoms each, are passed, preferably continuously, at temperatures between 2 and 50.degree. C. and at a maximum flow velocity of 500 m/h through a fixed-bed, activated-carbon adsorber whose interior surface is preferably>100 m.sup.2 /kg. In this way it is possible to quantitatively free aqueous solutions of hydrocyanic acid from hydrocarbons, in particular from benzene, with means of relatively low technical complexity.

Abstract: In the process for preparing acetylene and hydrocyanic acid by pyrolyzing acrylonitrile in a reactor, the gaseous reaction products of the pyrolysis are quenched down to less than 100.degree. C. immediately, advantageously within seconds, preferably within .ltoreq.1 s, of leaving the pyrolysis zone.

Abstract: An ammoxidizable compound is reacted with an ammonium salt, especially an inorganic ammonium salt, in the presence of a source of oxygen and an ammoxidation catalyst at 100 to 700.degree. C., preferably 200 to 700.degree. C., in order to produce cyano compounds of the formula R--CN, in which R is H or an organic group.

Abstract: Process for recovering cyanide values from a mill tailings stream remaining after gold and silver have been leached from an ore, by treating the tailings stream containing both ore insolubles and remaining cyanide leachant, without a preliminary filtration, to acidification with an acid to a pH of at least 4, stripping the cyanide values therefrom with a stripping gas in a stripping column such as a baffle plate column wherein the average residence time of the column is sufficiently low that the pH of the stream does not rise above about 4 and the ore insolubles do not plug the column, introducing the stripping gas and stripped cyanide values into an absorbing column containing an alkaline liquor to absorb the cyanide values, recovering the absorbed cyanide values, and removing a stripped tailings stream reduced in cyanide values.

Abstract: This invention is a method for producing hydrocyanic acid by using an element which comprises a foraminous structure fabricated from a material consisting essentially of a metal selected from the group consisting of platinum, rhodium, palladium and alloys of mixtures thereof characterized by (a) a novel configuration whereby the initial product of the formula: curve the flat ratio (C/F) multiplied by mesh size (N) and wire diameter (d.sub.w), for said element is greater than at least about 0.08 and (b) where, for a given methane and ammonia throughput, the conversion efficiency is a function of the curve to flat ratio (C/F), wire diameter (d.sub.w) and mesh size (N) combination and conversion efficiency is improved by increasing the mesh size (N) for a given wire diameter, increasing the wire diameter (d.sub.w) for a given mesh size, and increasing the curve to flat ratio (C/F) to a ratio of above 1.0. Preferably the initial product of the formula is greater than 0.

Abstract: The manufacture of hydrogen cyanide by the catalytic reaction of air/oxygen, ammonia and a hydrocarbon gas employing an improved catalytic reaction zone comprising a sequential array of layers/piles in which the surface density of the catalyst in layers/piles decreases from the entrance to the exit of the catalytic reaction zone.

Abstract: The present invention provides a coating for electrodes for use in electrochemical cells having an electrochemically active species and an electrolyte. The coating contains active species material and is selectively permeable allowing for the diffusion of the active species through the coating during operation of the cell while providing a substantially impervious barrier to the electrolyte. The coating optionally further includes a polymer layer over the active species containing coating or layer for maintaining the mechanical integrity of the active species layer.Electrodes utilizing the coatings described herein may be used in primary and secondary cells over a wide range of operating temperatures to deliver better electrochemical performance even at room temperature.Methods of making the coating and an apparatus for performing these methods on a continuous basis are disclosed.A novel composition of matter is disclosed comprising lithium, silicon, and fluorine prepared by exposing lithium metal to SiF.sub.

Abstract: A method for recovery of metal and cyanide from plating baths and rinse waters includes formation of hydrogen cyanide by acid treatment of such solutions, followed by HCN removal through diffusion across a microporous membrane. The method is applicable in a system wherein soluable metal cyanides and metal cyanide complexes are concentrated through use of a basic anion exchange system. Free hydrogen cyanide is released from the anion exchange system by means of an acid regenerant. In a preferred application of the invention, HCN, once having diffused through the microporous membrane, is neutralized with sodium hydroxide, to form a sodium cyanide solution that can be returned to a plating bath.

Abstract: Reaction products of hydrogen cyanide are prepared by a process in which hydrogen cyanide prepared in a conventional manner by pyrolysis at from 250.degree. to 650.degree. C. over a solid under from 5 to 200 mbar is cooled to a temperature of from 200.degree. to -10.degree. C. together with the other pyrolysis products, the hydrogen cyanide is then fed to a chemisorption reaction with a base or with a carbonyl compound, and the reaction products of hydrogen cyanide which are formed therein are removed from the system and brought to atmospheric pressure. In this process, the handling of large amounts of hydrogen cyanide is avoided.

Abstract: The present invention provides a gel having excellent separation ability, operability and a long life, for separating useful components from a rhodanate-containing detoxication treated liquid. The gel consists of a cross-linked polymer with more than 50 weight % of repeating units which are composed of 2,3-dioxypropyl (meth)acrylate or 2,3-dioxypropyl (meth)allyl ether, and whose average particle diameter is more than 10.mu. and gel water content is from 30 to 150%. The present invention also provides a method of separation using said gel.

Abstract: A process is described for the substantially complete recovery of cyanide reagent and metal forming water soluble metal-cyanide complexes contained in mill effluents and waste waters. The process is comprised of a loading cycle wherein the metal-cyanide complexes are adsorbed onto a basic ion exchange resin and the free cyanide containing column effluent is returned to the mill. The metal ions, which are usually mostly copper, nickel and zinc, and the complexing cyanide are eluted in the subsequent regenerant cycle by an acid solution having controlled pH and controlled redox potential, the latter being measured against the saturated calomel electrode. The preferred oxidant to control the redox potential of the regenerant solution is hydrogen peroxide. The generated hydrogen cyanide is sparged with air, or removed by subatmospheric pressure from the regenerant solution, and dissolved in an alkaline scrubber solution for reuse. The metal ions are recovered from a bleed solution.

Abstract: A process is described by which copper and optionally silver and gold are recovered from sulfide and oxide ores, concentrates or slag, which contain the metals. The particulate materials are treated with an aqueous solution of an alkali cyanide or alkaline earth cyanide, the laden solution is filtered, if desired, a water-soluble sulfide compound is added to the laden solution or filtered laden solution, the laden solution is subsequently adjusted to a pH value below 5 by an addition of acid to precipitate the metal sulfide, which is filtered off, and the resulting hydrocyanic acid is recovered. The process steps of precipitation and filtration of the metal sulfide and the recovery of the free hydrocyanic acid contained in the filtrate are carried out under superatmospheric pressure of 1.5 to 15 bars. The precipitation is preferably effected at a pH value of 1.5 to 2.0. The free hydrocyanic acid is recovered as alkali cyanide or alkaline earth cyanide and is recirculated to the leaching stage.

Abstract: Processes for carrying out catalytic exothermic and endothermic high-pressure gas reactions with a single-walled pressure vessel or shell containing cross-flow (e.g., radial flow) heat transfer exchangers, a continuous catalytic bed having at least two stages, and means for effecting "cross-over" material flows from "outside" to "inside" (for exothermic reactions) and vice versa (for endothermic reactions), whereby conditions of: maximum gas temperature always being in the core of said vessel or shell, minimal pressure drop, and minimal compression of catalyst particles are achieved, along with significant economic savings in cost of the pressure vessel or shell and catalyst (through extension of catalyst life).

Abstract: Hydrogen cyanide is produced by reacting an organic nitrile with hydrogen at temperatures of 400-700.degree. C in the presence of selected catalysts. Exemplary is the reaction of benzonitrile and hydrogen at 600.degree. C in the presence of chromia on alumina to produce hydrogen cyanide.

Abstract: The salt of a weak acid and a weak base is removed from a solution by contacting said solution with an emulsion. Said emulsion comprises an exterior phase which is characterized as immiscible with said solution and permeable to the weak acid and/or weak base in their un-ionized forms. One of the species which can permeate through said exterior phase reacts with a reactant present in the interior phase of the emulsion which converts said permeating species to a non-permeable form, i.e., by neutralization, thus providing a continuing driving force for the permeation of said permeating species. The other nonreacting or nonpermeating species is stripped from solution by passing an inert gas through said solution. Stripping and neutralization in the interior phase of the emulsion are carried out simultaneously.

Abstract: An improved process for recovery of hydrogen cyanide contained in a gaseous mixture is provided which comprises (a) contacting the gaseous mixture with an aqueous solution of an alkali metal carbonate to form an aqueous solution of the alkali metal cyanide and the corresponding bicarbonate, (b) contacting the aqueous solution of (a) with a ketone to produce a cyanohydrin-ketone mixture immiscible in the aqueous solution and a regenerate the alkali metal carbonate, separating the alkali metal carbonate solution and returning it to the gas absorption step (a) and recovering the cyanohydrinketone mixture. Alternately, the cyanohydrin in the cyanohydrin-ketone mixture of step (b) can be decomposed to the corresponding ketone and hydrogen cyanide.