Antimony compounds, reaction

This reaction gives fair-to-good yields of monoorganotin tribromides and trichlorides when quaternary ammonium or phosphonium catalysts are used (149). Better yields are obtained with organic bromides and staimous bromide than with the chlorides. This reaction is also catalyzed by tri alkyl antimony compounds at 100—160°C, bromides are more reactive than chlorides in this preparation (150,151). a,C0-Dihaloalkanes also react in good yield giving CO-haloalkyltin trihaHdes when catalyzed by organoantimony compounds (152). 

Additive inhibitors have been developed to reduce the contaminant coke produced through nickel-cataly2ed reactions. These inhibitors are injected into the feed stream going to the catalytic cracker. The additive forms a nickel complex that deposits the nickel on the catalyst in a less catalyticaHy active state. The first such additive was an antimony compound developed and first used in 1976 by Phillips Petroleum. The use of the antimony additive reportedly reduced coke yields by 15% in a commercial trial (17). 

Other synthetic pathways for the preparation of group-13-element antimony compounds include dehydro- and dehalosilylation reactions of R2SbSiMe3 or Sb(SiMe3)3 with R MX or MX3 (R = SiMe3, t-Bu R = Me, Et, i-Bu M = Ga, In X = H, Cl).53 A review of the chemistry of these potential precursors for 13-15 semiconductors was recently published.55... 

The transesterification and glycolysis reactions proceed via the Aac2 mechanism described above in Section 2.1. The reactions are acid catalyzed as demonstrated by Chegolya el al. [27], who added TPA to the polycondensation of PET and observed a significant increase of the apparent reaction rate. The industrial polycondensation process is accelerated by the use of metal catalysts, with these being mainly antimony compounds. 

This renders the halogen unavailable for reaction with the antimony compound, and therefore neither the halogen nor the antimony are transported into the flame zone during combustion. 

By the action of nascent hydrogen evolved from nine and sulphuric acid upon soluble antimony compounds. In both these reactions the antimouioua hydride is ways mixed with much hydrogen ... 

Direct reaction of diphenols and dicarboxylic acids in a molten state can be catalysed by adding tin, titanium or antimony compounds such as n-butylstannic acid or tetraoctyl titanate, and values of qinh ranging above 3.0 have been obtained 99). 

Quite often additional trifluorosilane can be obtained by simply returning the unreacted silane to the reaction vessel and allowing additional reaction time. A single reaction period yields about 1.5 g. (65% based on HSiCl3 employed) of product having an observed molecular weight of 86.9 (calcd. 86.1) and an infrared spectrum consistent with pure trifluorosilane.11 However, on some occasions the product is contaminated with silicon tetra-fluoride due to a reaction of the antimony compounds with the trifluorosilane. The silicon tetrafluoride impurity does not interfere with the preparation of tetracarbonyl(trifluorosilyl)cobalt. 

Only a few reports deal with reactions of arsenic and antimony compounds with HFA. Several reports describe insertion of HFA into As—H bonds 43, 72, 155). In contrast to the heavier group IV elements, insertion leads to the formation of 2-arsanoperfluoropropanols 87. This difference can be explained by assuming nucleophilic attack by the arsenic lone pair on the highly electrophilic carbonyl carbon. 

It is now conventional to use antimony oxides, or other Sb- compounds, as synergists with halogen-contaning flame retardants. The synergistic effect of the antimony compounds is correctly attributed to the formation of volatile antimony trihalides SbXj which affect the flame reactions The more SbOj is releas into the... 

Main gruup catalysis was also studied and magnesium [212], aluminum [213], tin [214-216] and antimony compounds (217, 218] activate the reaction path shown in Equation (39). 

SAFETY PROFILE A poison by inhalation. A very reactive, corrosive liquid to skin, eyes, mucous membranes. See also FLUORIDES and ANTIMONY COMPOUNDS. Violent reaction with phosphates. When heated to decomposition it emits very toxic fumes of F and Sb. 

SAFETY PROFILE Moderately toxic by intraperitoneal route. See also ANTIMONY COMPOUNDS and SULFIDES. Flammable when exposed to heat or by chemical reaction with powerful oxidizers. Use water to fight fire. Moderately explosive when shocked or by spontaneous chemical reaction in contact with powerful oxidizers. When heated to decomposition or on contact with acid or acid fumes it emits highly toxic fumes of oxides of sulfur and antimony. Incompatible with water or steam to produce toxic and flammable vapors and with oxidizers, e.g., Ag(C103)2, HCIO3,... 

SAFETY PROFILE Poison by skin contact and subcutaneous routes. Human systemic effects by skin contact with very small amounts primary irritant, corrosive. Explodes on contact with potassium, white phosphorus. Ignites on contact with antimony. Vigorous reaction with metal oxides (e.g., silver oxide, lead(II) oxide, lead(IV) oxide, lead(II)(IV) oxide). When heated to decomposition it emits very toxic fumes of Cl" and Se. See also SELENIUM COMPOUNDS and CHLORIDES. 

SAFETY PROFILE Poison by inhalation. Potentially explosive decomposition at 200°C. Flammable when exposed to heat or flame. Explosive reaction with ammonia + heat, chlorine, concentrated nitric acid, ozone. Incompatible with oxidants. The decomposition products are hydrogen and metallic antimony. When heated to decomposition it emits toxic fumes of Sb. Used as a fumigating agent. See also ANTIMONY COMPOUNDS and HYDRIDES. 

The reaction of oxiranes and CO2 yields 1,3-dioxolanones in the presence of various catalysts, such as organic antimony compounds, organic tin compounds, MoCl5-Ph3P, a mixture of phenols, alkali metal iodides, and metal oxides, and Ni° complexes (Eq. 201). ... 

The course of the reaction may be followed by gas-liquid chromatography using a silicone oil stationary phase. The reaction is complete after about 3 hours and the mixture is then filtered and the solvent removed under reduced pressure. An opaque gum remains and is extracted with five 100-mL portions of hot petroleum ether (40-60° fraction). About 1 mL of water is then added to the combined extracts and, on shaking, any antimony compounds remaining are precipitated. Filtration gives a clear solution to which is added another few drops of water to ensure completeness of separation of antimony residues. The water is removed and the solution is dried over anhydrous CaCh for 2 hours. Removal of the petroleum ether under reduced pressure gives a colorless liquid of sufficient purity for the reaction with HBr (Sec. D). 

In commercial practice, all PET is made using an antimony compound for the final polycondensation stage. The transesterification reaction between DMT and the glycol is catalysed by salts of manganese, zinc, calcium, cobalt, or other metals. At the end of the ester-interchange stage, when essentially all of the methanol has been evolved, the transesterification catalyst is converted to a catalytically inactive and substantially colourless form by reaction with a phosphorus compound such as triphenyl phosphate or phosphite. Polyesters of 1,4-cyclo-hexanedimethanol and DMT or TA are made using complex titanium catalysts. 

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