Hydrogen halides, reaction with

The introduction of phosphine into liquid hydrogen chloride results in the formation of PH4CI 95.328). j jg observed earlier similarly 

PH4Br can be obtained from hydrogen bromide and phosphine 307,309,328) 

Both phosphonium halides are almost completely dissociated at room temperature and normal pressure. 

The reaction between dry phosphine and hydrogen iodide, first described in 1817 by J. J.Houtonde la Billardiere produces phosphonium iodide. The simplest laboratory preparation of this compound is by the hydrolysis of an intimate mixture of diphosphorus tetraiodide and white phosphorus According to X-ray diffraction investigations, phosphonium iodide crystallises in a caesium chloride type lattice 3m,32s). 326) hydrogen atoms 

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The major portion of the present chapter concerns the conversion of alcohols to alkyl halides by reaction with hydrogen halides... 

Reaction with hydrogen halides (Sec tion 4 7) The order of alcohol reactiv ity parallels the order of carbocation staiiility RjC" > R2CH > RCHj" > CHj" Benzylic alcohols react readily... 

Just as the carbon-oxygen bond of alcohols is cleaved on reaction with hydrogen halides (Section 4 8) so too is an ether linkage broken... 

Because phenols are not converted to aryl halides by reaction with hydrogen halides reac tion proceeds no further than shown m the preceding general equation For example... 

Two kinds of starting materials have been examined in nucleophilic substitution reactions to this point. In Chapter 4 we saw that alcohols can be converted to alkyl halides by reaction with hydrogen halides and pointed out that this process is a nucleophilic substitution taking place on the protonated fonm of the alcohol, with water serving as the... 

Glycosyl halides, a very important group of carbohydrate derivatives, are commonly prepared14 from per-O-acylated sugars by reaction with hydrogen halides or halides of aluminum or titanium. The selection of the method depends mainly on the anomeric configuration of the substrate, the kind of its O-acyl groups, and the stability of the product to be prepared. 

I. Reaction with hydrogen halides Alcohols react with hydrogen halides to form alkyl halides (Refer Unit 10, Class Xll). 

Analytically, epoxy groups are determined by the reaction with hydrogen halide and back titration with a standard base. Other functional groups present may cause interference problems and result in poor end points. Pyridinium chloride-pyridine is a recommended reagent for the analysis of bisphenol-diglycidyl ether resins [22,23],... 

Secondary and tertiary alcohols undergo S l reactions with hydrogen halides. The reaction of an HX with 3° alcohol proceeds readily at room temperature, whereas the reaction of an HX with a 2° alcohol requires heat. 

Since reactive species such as H , OH, and R would be formed in greater concentrations at ignition temperatures than at lower temperatures, their reactions with hydrogen halides (shown below) would be important in ignition. 

Alcohols and phenols are also weak bases. They can be protonated on the oxygen by strong acids. This reaction is the first step in the acid-catalyzed dehydration of alcohols to alkenes and in the conversion of alcohols to alkyl halides by reaction with hydrogen halides. Alkyl halides can also be prepared from alcohols to alkyl halides by reaction with hydrogen halides. Alkyl halides can also be prepared from alcohols by reaction with thionyl chloride or phosphorus halides. 

N Reactions of the betaines I with initial cleavage of the P-N bond (type B) are rarely observed. One example is the reaction with hydrogen halides leading to dihalogeno phosphates and -thiophosphates ... 

Organotin halides can also be obtained from oxides or hydroxides on reaction with hydrogen halides (or ammonium halides) (equation 61) and from tin-tin bonded species on reaction with halogens (equation 62). 

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