Abstract: Interchange reactions between organosulfides and mercaptans are promoted by the use of catalysts containing tungsten and molybdenum oxide.

Abstract: A cracking catalyst used to crack oil to produce gasoline or higher-boiling hydrocarbon fuel is contacted with both (A) antimony or a compound thereof such as antimony tris(0,0-dipropyl phosphorodithioate) and (B) a modifying composition consisting essentially of carbon, hydrogen, nitrogen, and sulfur produced by the treatment of a metal salt of a dialkyl dithiocarbamate with a hydrolyzable germanium (IV) compound such as germanium tetrachloride, the contacting of the catalyst with (A) and (B) prior to, during, or after use of the catalyst in a cracking process being effective in precluding or reducing adverse effects of metals such as nickel, vanadium, and iron.

Abstract: A cracking catalyst used to crack oil to produce gasoline or higher-boiling hydrocarbon fuel is contacted with both (A) antimony or a compound thereof such as antimony tris(O,O-dipropyl phosphorodithioate) and (B) a modifying composition consisting essentially of carbon, hydrogen, nitrogen, and sulfur produced by the treatment of a metal salt of a dialkyl dithiocarbamate with a hydrolyzable germanium (IV) compound such as germanium tetrachloride, the contacting of the ctalyst with (A) and (B) prior to, during, or after use of the catalyst in a cracking process being effective in precluding or reducing adverse effects of metals such as nickel, vanadium, and iron.

Abstract: Gallium compounds are usefully employed to modify hydrocarbon cracking catalysts.

Abstract: Deposits on a cracking catalyst are passivated by contacting the cracking catalyst with tin and at least one of phosphorus or sulfur.

Abstract: Antimony passivators for cracking catalysts are rendered more stable by employing excess alcohol during their preparation.

Abstract: In the present invention, an epitaxial layer of a doped III-V alloy is grown on a semiconductor substrate by a molecular beam epitaxy process using a molecular beam of lead together with molecular beams of the constituent elements of the doped III-V alloy. The magnitude of the lead flux is sufficient to form and maintain a presence of from 5 to 20% of a monolayer of lead on the growth surface. The technique is directed particularly to ternary and quaternary III-V compositions.

Abstract: Gallium compounds are usefully employed to modify hydrocarbon cracking catalysts.

Abstract: A novel cracking catalyst, a method of preparing same, and an improved hydrocarbon cracking process are provided wherein the adverse effects of metals such as nickel, vanadium, iron, copper, and cobalt on the cracking catalys are reduced by contacting the cracking catalyst with a sufficient amount of at least one indium modifier selected from the group consisting of elemental indium and indium compounds free of the element antimony.

Abstract: A method of extruding polypropylene filaments in which the polypropylene is extruded at a temperature below 375.degree. F., such as in the range 335.degree. F. to 365.degree. F., particularly about 350.degree. F., into a quiescent hot zone having a temperature sufficiently high to retard cooling of the extruded polypropylene filaments. The filaments are then passed through and cooled in a quench zone across which cooling air is blown. The polypropylene has a narrow molecular weight distribution with a swell value less than 2.5, and its melt flow may be greater than 30. The yarn is drawn-down in the hot zone and the filaments may be drawn-down to an undrawn denier of less than 15 with substantial elimination of resonance.

Abstract: An extruder screw for extruding solution dyed polypropylene at low temperatures, for example, in the range 335.degree. F. to 365.degree. F., has feed, transition and metering sections, the length of the transition section being at least equal to the sum of the lengths of the feed and metering sections. The transition section has a compression ratio of at least 4.5:1 to create substantial backflow of the melt therein to thoroughly mix the melt. The transition section may be a continuous compression zone or have two compression portions connected by a dwell portion.

Abstract: A method of melt spinning solution dyed polypropylene filaments, with quicker color changes, comprises passing solution dyed polypropylene melt of a first color at a temperature below 400.degree. F., particularly in the range 350.degree. F. to 360.degree. F., through a plurality of shallow horizontally disposed cavities in a spin pack. Each cavity contains a set of horizontally disposed mesh screens which occupies at least one-third of the depth thereof, the melt passing through all of the sets of mesh screens and occupying only a low internal volume in the spin pack as it passes therethrough and is extruded therefrom. Then, when it is needed to change color, natural polypropylene melt is passed through the spin pack and natural filaments extruded. Thereafter, solution dyed melt of a second color is passed through the spin pack and filaments of the second color extruded, the color change from the first color to the second color being effected quickly and completely by purging through the spin pack.

Abstract: Deposits on a cracking catalyst are passivated by contacting the cracking catalyst with tin and at least one of phosphorus or sulfur.

Abstract: A method of extruding multi-filament polypropylene yarn in which the polypropylene is extruded at a temperature below 425.degree. F., such as in the range 415.degree. F. to 350.degree. F., particularly about 400.degree. F., into a hot zone having a temperature sufficiently high to retard cooling of the extruded polypropylene yarn. The temperature of the hot zone can be within 60.degree. F. of the temperature of extrusion. The yarn is then passed through a quenching zone across which air is blown to cool the yarn. The swell value of the polypropylene can be less than 3 and its melt flow may be greater than 30. The yarn is drawn down in the hot zone and the filaments may be drawn down to an undrawn denier of less than 40.

Abstract: A used petroleum or hydrocarbon conversion or cracking catalyst having metal contaminants thereon which are leachable by water therefrom is treated with tin and/or indium and/or a compound of tin and/or a compound of indium to reduce leachability of said metal therefrom rendering the thus treated contact mass or catalyst more safe to be disposed of at a landfill.

Abstract: A passivating agent is added to a cracking catalyst which has not been previously treated with the passivating agent by mixing the untreated cracking catalyst with a refractory material which has been previously treated with a passivating agent. At least a portion of the passivating agent is transferred by inter-particle transfer from the treated refractory material to the untreated cracking catalyst.A passivating agent may also be recovered from a previously treated cracking catalyst which has become contaminated by contacting the contaminated cracking catalyst with a refractory material which has not previously been treated with the passivating agent. At least a portion of the passivating agent will transfer by inter-particle transfer from the contaminated catalyst to the refractory material while the contaminants on the contaminated cracking catalyst will not transfer.

Abstract: A novel cracking catalyst, a method of preparing same, and an improved hydrocarbon cracking process are provided wherein the adverse effects of metals such as nickel, vanadium, iron, copper, and cobalt on the cracking catalyst are reduced by contacting the cracking catalyst with a sufficient amount of at least one indium modifier selected from the group consisting of elemental indium and indium compounds free of the element antimony.

Abstract: Air quench extrusion apparatus and method are described for extruding yarn from polyolefin material. The yarn is first extruded downwards into a hot zone surrounded by a shroud, and then passes through a quenching zone across which cooling air, or gas, is moved to cool the yarn. Immediately adjacent the lower end of the quenching zone is disposed a denier control roll for pulling the yarn out of the quenching zone at a controlled rate causing the yarn to be drawn down in denier in the hot zone. The hot zone is small in volume relative to the quenching zone and contains quiescent air at a temperature close to that at which the material is extruded. The height of the apparatus from extrusion to the denier control roll is less than 10 feet, allowing the apparatus to be located in a single story building. At least two multi-filament yarns are simultaneously extruded into the hot zone which is rectangular in cross-section.

Abstract: Apparatus and method are described for extruding filaments of thermoplastic material, particularly polypropylene, by liquid quench melt spinning in which a baffle arrangement is disposed in the quench liquid around the location where the filaments enter to reduce turbulence, vortexing, and liquid level variation. The baffle arrangement forms an opentopped box-like structure with two quench liquid inlet apertures and one quench liquid outlet aperture. Yarn guides are disposed inside this structure and the filaments, after solidifying, pass around the yarn guides and then upwards, at an angle of about 30 degrees to the horizontal, through the quench liquid outlet aperture. The passage of the filaments creates a pumping action of the quench liquid in through the two inlet apertures and out through the outlet aperture. The area of the outlet aperture is less than the sum of the areas of the inlet apertures, to create an inefficient pump.

Abstract: A method of extruding multi-filament polypropylene yarn in which the polypropylene is extruded at a temperature below 425.degree. F., such as in the range 415.degree. F. to 350.degree. F., particularly about 400.degree. F., into a hot zone having a temperature sufficiently high to retard cooling of the extruded polypropylene yarn. The temperature of the hot zone can be within 60.degree. F. of the temperature of extrusion. The yarn is then passed through a quenching zone across which air is blown to cool the yarn. The swell value of the polypropylene can be less than 3 and its melt flow may be greater than 30. The yarn is drawn down in the hot zone and the filaments may be drawn down to an undrawn denier of less than 40.