Abstract: Nitrogen oxides are effectively removed from a gaseous mixture comprising the same and oxygen by adding ammonia thereto and contacting with a suitable catalyst for the nitrogen oxide-ammonia reaction. While the presence of sulfur dioxide is not essential to such removal, best results are achieved when sulfur dioxide is also present in the gaseous mixture. When sulfur dioxide is present, and particularly when the same is present in a concentration in excess of that required for most effective nitrogen oxide conversion, the excess sulfur dioxide may be separated prior to the nitrogen oxide conversion, simultaneously therewith or subsequent thereto.

Abstract: Haloalkanethiols are synthesized through the free radical liquid phase reaction of halogenated olefins with an excess of hydrogen sulfide. High product yields to the desired haloalkanethiol products are secured when a 3 to 20 fold molar excess of hydrogen sulfide to halogenated olefin is used. Desirably, the synthesis is carried out to a conversion level not exceeding 90%. The haloalkanethiol products can be subsequently dehydrohalogenated to the corresponding episulfide products by reacting the haloalkanethiol product with a substantially equal molar amount of anhydrous ammonia.

Abstract: Improved Crozat appliances useful in the treatment of maxillary and/or mandibular dental malocclusion are provided by the present invention. The improved appliance consists of clasp means that have anterior and interior sections and which are adapted to engage the outer periphery of a molar or premolar on each side of the dental arch. The clasp means are interconnected with a body wire which has an essentially flat spiral spring formed in a segment thereof and adapted to exert a spring extension force against the clasp means.

Abstract: High surface area alumina materials, which are particularly effective catalyst supports or carriers, are prepared by heating alumina monohydrate, alumina trihydrate or mixtures thereof from 450.degree.-500.degree. to at least 800.degree.F in the presence of excess elemental chlorine. The heating of the alumina material with elemental chlorine is conducted prior to said alumina material being heated to a temperature above about 450.degree.-500.degree.F in the absence of elemental chlorine. The alumina monohydrate or trihydrate compositions are derived from the aqueous phase reaction of ethylene oxide with aluminum chloride and/or aluminum hydroxychloride.

Abstract: Compositions comprising iridium and at least one additional metal, preferably platinum, are disclosed in which the iridium and the additional metal or metals are present on a refractory support as highly dispersed polymetallic clusters. The metallic atoms in a cluster are separated by distances of about 2.5 to 4.0A. The degree of coverage of the surface of said refractory support by said polymetallic clusters is lower than about 10% and frequently lower than about 1%. The compositions are useful as hydrocarbon conversion catalysts, and iridiumplatinum catalysts containing a halogen moiety are especially useful for promoting naphtha reforming reactions.

Abstract: Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residue-depleted catalyst with an elemental halogen-containing gas at a temperature of less than about 850.degree.F., (3) contacting the treated catalyst with hydrogen at elevated temperatures to reduce a substantial portion of the iridium present in the catalyst to its metallic form, and (4) contacting the catalyst from step (3) with an elemental halogen-containing gas at a temperature of at least about 850.degree.F. Steps (3) and (4) may be repeated, in sequence, at least one additional time to redisperse the iridium catalyst component to a highly active, high surface area state.

Abstract: Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst in a reaction zone with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residuedepleted catalyst in a reaction zone with hydrogen at an elevated temperature to reduce a substantial portion of the iridium present on the catalyst to its metallic form, (3) contacting the treated catalyst in a reaction zone with an elemental halogen-containing gas in a reaction zone with an elemental halogen-containing gas at a temperature greater than about 850.degree.F.

Abstract: Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by contacting the catalyst, prior to contact with oxygen at elevated temperature, with a chlorine-containing reagent to increase the catalyst chlorine content to at least 1.0 wt. %, based on anhydrous catalyst, and thereafter contacting the catalyst with a gaseous mixture containing oxygen, a chlorine containing reagent, and water at a temperature of about 750.degree. to 1000.degree.F. for a time sufficient to burn at least a portion of the carbonaceous residues from the catalyst.

Abstract: Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residue-depleted catalyst with hydrogen at an elevated temperature to convert a substantial portion of the iridium present in the catalyst to its metallic form, (3) contacting the reduced catalyst with an elemental halogen-containing gas at a temperature of at least about 300.degree.C., and (4) repeating steps (2) and (3), in sequence, at least one additional time to thereby redisperse the iridium catalyst component to a highly active, high surface area state.