Aliphatic halogen compounds

In neutral or acidic medium, unactivated primary and secondary alkyl chlorides and bromides are not hydrogenolyzed over palladium, but iodides, as well as tertiary chlorides and bromides, are lost to some extent at least, on hydrogenation at room temperature and atmospheric pressure. 23. 24 an yi fluorides, 

Almost any type of base can be used to promote this reaction but potassium hydroxide and magnesium oxide 25 are particularly effective. Triethylamine was found to be inferior to potassium hydroxide. 26 if calcium. 

Halogens on a cyclopropane ring can be removed without hydrogenolysis of the ring itself. The selective removal of one bromine from 1,1-dibromo-cyclopropanes occurred over palladium on charcoal or platinum oxide in methanolic potassium hydroxide at room temperature and atmospheric pressure. Complete debromination resulted from the use of Raney nickel under the same conditions (Eqn. 20.56). 31 

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Table 111,42 deals with a number of aliphatic halogen compounds together with their crystalline derivatives. Some aromatic compounds, which simulate the properties of aliphatic haUdes in some respects, are included. 

Aliphatic Halogen Compounds, Table III, 42 Aromatic Halogen Compounds, Table IV, 28. Aliphatic Ethers, Table III, 60. 

The alkali salts of thiophenethiols react normally with aliphatic halogen compounds to give and have also been... 

It is only in relatively recent years that the interaction of indole Grignard reagents with unsaturated aliphatic halogen compounds has... 

B. Sample Mass Spectrum of an Aliphatic Halogenated Compound... 

Heating the Tube.—Place the iron case with its tube in a bomb or tube furnace in such a way that the end with the capillary is raised somewhat and directed towards the wall on which a shield is fixed and close the furnace. Several tubes may be heated simultaneously. Light all the burners and heat gradually to the desired temperature, regulating the gas supply at the main tap. For aliphatic halogen compounds (and many sulphur compounds) this temperature is about 250°, for the aromatic compounds (and sul-phonic acids) it is about 300°. Most substances are completely oxidised after three to four hours, but in the case of aromatic compounds the heating is continued for some hours longer. 

McLafferty, F.W. Mass Spectrometric Analysis. 1. Aliphatic Halogenated Compounds. Anal. Chem. 1962,34,2-15. 

Devotta, S., and V. R. Pendyala, Modified Joback Group Contribution Method for Normal Boiling Point of Aliphatic Halogenated Compounds. Ind. Eng. Chem. Res., 1992 31, 2042-2046. 

Reaction XXXVUI. (a) Action of Aqueous and Alcoholic Potassium or Sodium Cyanide on Aliphatic Halogen Compounds, and Hydrolysis of the Nitriles so formed. (B., 14, 1965 15, 2318.)—The preparation and hydrolysis of nitriles are dealt with on p. 151 and p. 239 respectively. In many cases, however, it is unnecessary to isolate the nitrile it can be directly hydrolysed to the corresponding acid on its formation. Among others, the following syntheses have been carried out in this way — i (i.) w-Valeric acid [jpentan acid] from w-butyl bromide (Am. Soc., 42, 310). 

Reaction CXXXII. Action of Aliphatic Halogen Compounds on Aliphatic or Aromatic Primary Amines.—Secondary, tertiary and quaternary compounds may be formed. 

Table 10.10, deals with a number of aliphatic halogen compounds together with their crystalline derivatives. 

In analogy to the reduction of aliphatic halogen compounds, the reduction of sulfonates can be used for the alkylation of phenylacetic acids 435) ... 

There has been a growing interest in applying high performance liquid chromatography, to the determination of the not only volatile compounds, such as aliphatic and polyaromatic hydrocarbons, saturated and unsaturated aliphatic and polyaromatic hydrocarbons, saturated and unsaturated aliphatic halogen compounds, haloforms and some esters, phenols and others but also non volatile components of water. 

Other applications of gas chromatography to the determination of haloforms and aliphatic halogen compounds in non saline waters are discussed in Table 15.9. 

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