Arsenic chloride catalysts

Poisons for the nickel catalyst are sulfur, arsenic, chlorides or other halogens, phosphates, copper and lead. A 15 percent nickel catalyst is poisoned at 775°C if the gas contains as little as 0.005 percent (50 ppm) sulfur. 

Another early development of the Bart procedure was the use of diazonium fluoroborates instead of the more usual chlorides 144, 145). Subsequently Doak and Freedman 146) found that dry diazonium fluoroborates react with arsenic trichloride in dry ethanol to give both arsonic and arsinic acids. Under these conditions maximum yields of the arsonic acid are obtained using a cuprous chloride catalyst. In 80% ethanol quite high yields of the arsinic add are obtained using cuprous bromide as catalyst. These workers later found that fluorozincates and fluorosilicates give similar results 147). 

Poisons for the nickel catalyst are sulfur, arsenic, chlorides or other halogens, phosphates. and copper or lead. A 15 percent nickel catalyst is poisoned at 775°C, should the gas contain 0.005 percent sulfur. This is equivalent to reaction of all the nickel on the surface of the crystallites 1 micron in diameter. For lower operating temperatures, the amount required for poisoning is even lower. When using naphtha as a feedstock, 0.5 ppm of sulfur (w/w) in the naphtha is the maximum allowed concentration for operation at 775°C. 

The success of the Bart reaction when applied to nuclear- substituted anilines is often much affected by the pH of the reaction-mixture. Furthermore, the yields obtained from some m-substituted anilines, which under the normal conditions are usually low, arc considerably increased by the modifications introduced by Scheller, and by Doak, in which the diazotisation is carried out in ethanolic solution followed by reaction with arsenic trichloride in the presence of a cuprous chloride or bromide catalyst. 

When heated, polyvinyl chloride (PVC) and polyvinyl alcohol (PVA) lose HC1 and H20, respectively, to produce dark-colored conductive polyacetylene. Superior polymers of acetylene can be made by the polymerization of acetylene with Ziegler-Natta catalysts. The conductivity of polyacetylene is increased by the addition of dopants, such as arsenic pentafluoride or sodium naphthenide. 

By the action of chlorine and chlorine compounds on arsenic pentoxide. Arsenic trichloride is formed when chlorine is passed over the heated oxide.16 Hydrogen chloride reacts at ordinary temperatures, but not at -20° C.17 Aqueous hydrochloric acid, or sulphuric acid and a metallic chloride, also reacts with the oxide or with alkali arsenates to produce arsenic trichloride. The reaction with hydrochloric acid is greatly influenced by catalysts such as ferrous sulphate18 or chloride,19 potassium bromide20 or iodide,21 hydrobromic acid,22 methyl alcohol23... 

Reactions of a,(3-unsaturated ketones with anilines are not very diverse and usually yield the appropriate quinolines [204, 205, 206, 207, 208, 209, 210, 211]. As catalysts in such reactions, hydrochloric acids are often used [204, 205, 206, 207]. In [208] besides hydrochloric acid, the use of arsenic acid and zinc chloride was proposed, which led to increase of the yields. In [209] it was reported that the catalyst used was 3-nitrobenzensulfonic acid (Scheme 3.74). 

Thionyl fluoride can be prepared by the reaction of thio-nyl chloride with metal fluorides such as zinc(II) fluoride1 and arsenic (III) fluoride,2 and with metal fluorosulfites.3 It is also obtained by the action of hydrogen fluoride upon a mixture of tetrasulfur tetranitride and copper(II) oxide4 and by the reaction of hydrogen fluoride with thionyl chloride in the absence of6 or in the presence of6 antimony(V) fluoride as catalyst. Another method and the simplest on a laboratory scale involves the reaction of antimony(III) fluoride with thionyl chloride in the presence of antimony ) chloride as catalyst.7 This last procedure is described below. 

The redistribution reaction in lead compounds is straightforward and there are no appreciable side reactions. It is normally carried out commercially in the liquid phase at substantially room temperature. However, a catalyst is required to effect the reaction with lead compounds. A number of catalysts have been patented, but the exact procedure as practiced commercially has never been revealed. Among the effective catalysts are activated alumina and other activated metal oxides, triethyllead chloride, triethyllead iodide, phosphorus trichloride, arsenic trichloride, bismuth trichloride, iron(III)chloride, zirconium(IV)-chloride, tin(IV)chloride, zinc chloride, zinc fluoride, mercury(II)chloride, boron trifluoride, aluminum chloride, aluminum bromide, dimethyl-aluminum chloride, and platinum(IV)chloride 43,70-72,79,80,97,117, 131,31s) A separate catalyst compound is not required for the exchange between R.jPb and R3PbX compounds however, this type of uncatalyzed exchange is rather slow. Again, the products are practically a random mixture. 

Phosphorus(III) fluoride can be prepared by the reaction of antimony (III) fluoride with phosphorus (III) chloride, using antimony (V) chloride as a catalyst,1 or by heating copper phosphide with lead fluoride.2 The procedure described here involves the reaction of arsenic(III) fluoride with phosphorus (III) chloride, using antimony(Y) chloride as a catalyst.3,4... 

Many studies on the direct reaction of methyl chloride with silicon-copper contact mass and other metal promoters added to the silicon-copper contact mass have focused on the reaction mechanisms.7,8 The reaction rate and the selectivity for dimethyldichlorosilane in this direct synthesis are influenced by metal additives, known as promoters, in low concentration. Aluminum, antimony, arsenic, bismuth, mercury, phosphorus, phosphine compounds34 and their metal complexes,35,36 Zinc,37 39 tin38-40 etc. are known to have beneficial effects as promoters for dimethyldichlorosilane formation.7,8 Promoters are not themselves good catalysts for the direct reaction at temperatures < 350 °C,6,8 but require the presence of copper to be effective. When zinc metal or zinc compounds (0.03-0.75 wt%) were added to silicon-copper contact mass, the reaction rate was potentiated and the selectivity of dimethyldichlorosilane was enhanced further.34 These materials are described as structural promoters because they alter the surface enrichment of silicon, increase the electron density of the surface of the catalyst modify the crystal structure of the copper-silicon solid phase, and affect the absorption of methyl chloride on the catalyst surface and the activation energy for the formation of dimethyldichlorosilane.38,39 Cadmium is also a structural promoter for this reaction, but cadmium presents serious toxicity problems in industrial use on a large scale.41,42 Other metals such as arsenic, mercury, etc. are also restricted because of such toxicity problems. In the direct reaction of methyl chloride, tin in... 

Biswas and Mishra reported that arsenic trichloride can initiate the polymerisation of a-methylstyrene in benzene and methylene chloride at 25°C. No exhaustive study was made of this system. The same authors also reported that PCI3, PBra and POCI3 are effective initiators for the polymerisation of a-methylstyrene, particularly in nitrobenzene. The latter catalyst was selected for a more detailed investigation water was considered as detrimental to initiation, which was postulated to occur directly as... 

When acetylene is passed izito anhydrous arsenic trichloride, only slight absorption of the gas takes place, and the gas is again evolved if the liquid is boiled. This points to no chemical reaction taking place, or only one in which the compounds formed arc decomposed by heat. If, however, anhydrous aluminium chloride is used as a catalyst, a... 

PLATINUM (7440-06-4) Pt Powdered form is highly reactive catalyst, and may cause fire and explosions on contact with many substances including oxidizers, acetone, strong acids, finely divided aluminum, dioxygen difluoride, ethyl alcohol, hydrazine, hydrogen peroxide, lithium, methyl hydroperoxide, nitrosyl chloride, ozonides, peroxymonosulfliric acid, red phosp] oms. Incompatible with ammonia, arsenic, chlorine dioxide, hydrogen, methyl hydroperoxide, selenium, tellurium, vanadium dichloride. 

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