Calcium halides iodide

The conversion of alcohols to iodides with inversion using triphenylphosphine-iodine-imidazole, or triphenylphosphine-2,4,5-tri-iodoimidazole, (4,157) has now been described in detail. The purity and yield of tertiary iodides (or bromides) prepared from the alcohols and aqueous HI (or HBr) at 0 can be improved by addition of lithium or calcium halides it is believed the metal salts retard competing hydrolysis of the tertiary halides. Secondary alkyl bromides have been prepared from the alcohols with retention of configuration via the inverted selenides (Scheme 35). Two other new reagents for the... 

Dissolve 37.5 g (0.25 mol) of dry sodium iodide (1) in 250 ml of dry acetone in a 500-ml flask fitted with a reflux condenser protected by a calcium chloride guard-tube, and add 30.2 g (25 ml, 0.2 mol) of l-bromo-3-methylbutane. A precipitate of sodium bromide soon begins to form leave the reaction mixture at room temperature for 30 minutes, and then boil under reflux for 45 minutes to complete the reaction. Allow to cool and filter off the sodium bromide, washing the residue with a little acetone. Remove the acetone from the filtrate on a rotary evaporator, and shake the residual organic halide with 100 ml of water. Separate the lower dark-coloured layer and wash it twice more with 50 ml portions of water incorporate sufficient crystals of sodium thiosulphate into the first portion of wash-water to decolourise the organic phase. Dry the product over anhydrous calcium sulphate, filter and distil, collecting the l-iodo-3-methylbutane at 145-147 °C. The yield is 26 g (66%). 

Metal Halides. Reacts explosively or violently with the following calcium bromide iron(III) bromide or chloride iron(II) bromide or iodide cobalt(II) chloride silver fluoride all four mercury(II) halides copper(I) chloride, bromide or iodide copper(II) chloride and bromide ammonium tetrachlorocuprate zinc and cadmium chlorides, bromides, and iodides aluminum fluoride, chloride, and bromide thallium bromide tin(II) or (IV) chloride tin(IV) iodide arsenic trichloride and triiodide antimony and bismuth trichlorides, tribromides, and triiodides vanadium(V) chloride chromium(IV) chloride manganese(II) and iron(II) chlorides and nickel chloride, bromide, and iodide.17,22"25... 

H2O2, hydrogen chloride, hydrazine, Pb20Cl2, Pb02, PbS04, maleic anhydride, metal halides (e.g., calcium bromide, iron(III) bromide, iron(III) chloride, iron(II) chloride, iron(II) bromide, iron(II) iodide, cobalt(II) chloride, chromium tetrachloride, silver fluoride, mercury(II) bromide, mercury(II) chloride, mercury(II) fluoride, mercury(II) iodide, copper(I) chloride. 

RC = CCH,X — RCX = C==CH,. /S.y- and 7,S-Acetylenic alcohols can be transformed to the halides in better yields by an alternative procedure, which consists in their esterification with p-toluenesulfonyl chloride and subsequent cleavage of the ester by the action of sodium iodide, lithium chloride, or calcium bromide in an appropriate solvent (60-90%). Halo ethers are prepared by the action of phosphorus tribromide on hydroxy ethers, as in the preparation of /3-ethoxyethyl bromide (66%). In a similar manner, /3-halo esters have been prepared without appreciable dehydration of the /3-hydroxy ester (40-60%). The reaction of cyanohydrins leads to a-halo nitriles. Treatment of 2-nitro-l-propanol with phosphorus pentachloride gives l-chloro-2-nitropropane (47%). ... 

The catalysts used are bromine, iodine, haloamides I and/or polymerization inhibitors, in general in amounts of from 0.0001 to 0.1 preferably from 0.001 to 0.05, mole of catalyst per mole of methyi ketone. Instead of the above catalysts, it is also possible to usr compounds which form such catalysts under the reaction conditions, e.g to use bromides and iodides in place of bromine or iodine. Water-soluble halides are preferred and are advantageously used in the form of thei alkaline earth metal salts or, especially, their alkali metal salts, e.g calcium bromide, calcium iodide, magnesium bromide, magnesiais iodide, lithium bromide, lithium iodide and especially sodium bromide or iodide or potassium bromide or iodide... 

The obtained solubility data are presented in Table 3.7.19. The oxide-solubility changes in molten potassium halides can be explained successfully in the framework of the HSAB concept. Indeed, Ca2+ ion belongs to the hard acids, whereas chloride ion is a hard base, bromide ion is an intermediate base and iodide ion is a soft base. Therefore, the stability of calcium hahde complexes should reduce in the chloride-bromide-iodide sequence. Since an increase in the halide complex s stability results in the elevation of the oxide solubility in the melts, one should expect a reduction in the solubility of... 

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