Halogen acids, reactions

Plutonium reacts with hydrogen at high temperatures forming hydrides. With nitrogen, it forms nitrides, and with halogens, various plutonium hahdes form. Halide products also are obtained with halogen acids. Reactions with carbon monoxide yields plutonium carbides, whde with carbon dioxide, the products are both carbides and oxides. Such reactions occur only at high temperatures. 

Strictly speaking the alkyl halides are esters of the halogen acids, but since they enter into many reactions (t.g., formation of Grignard reagents, reaction with potassium cyanide to yield nitriles, etc.) which cannot be brought about by the other eaters, the alkyl halides are usually distinguished from the esters of the other inorganic acids. The preparation of a number of these is described below. 

Reaction with Other Inorganic Halogen Compounds. Anhydrous HCl forms addition compounds at lower temperatures with halogen acids such as HBr and HI, and also with HCN. These compounds are stable at room temperature. 

Reaction with Organic Compounds. Aluminum is not attacked by saturated or unsaturated, aUphatic or aromatic hydrocarbons. Halogenated derivatives of hydrocarbons do not generally react with aluminum except in the presence of water, which leads to the forma tion of halogen acids. The chemical stabiUty of aluminum in the presence of alcohols is very good and stabiUty is excellent in the presence of aldehydes, ketones, and quinones. 

Fire Hazards - Flash Point Not flammable Flammable Limits in Air (%) Not flammable Fire Extinguishing Agents Use water, foam, or dry chemical on adjacent flres Fire Extinguishing Agents Not to be Used Any agent with an acid reaction (e.g. carbon dioxide or halogenated agents) will... 

Annotinine, C gHjjOjN, (1). M.p. 232° perchlorate, m.p. 267°. In a later paper (1947) Manske and Marion record the results of the action of alkali and of halogen acids on annotinine, and of the oxidation of the base and discuss the reaction products. They conclude that two of the oxygen atoms are present as a lactone group and that the third oxygen may form an ether bridge in a 5- or 6-membered ring. 

It was pointed out earlier that the low nucleophilicity of fluoride ion and its low concentration in HF solutions can create circumstances not commonly observed with the other halogen acids. Under such conditions rearrangement reactions either of a concerted nature or via a true carbonium ion may compete with nucleophilic attack by fluoride ion. To favor the latter the addition of oxygen bases, e.g., tetrahydrofuran, to the medium in the proper concentration can provide the required increase in fluoride ion concentration without harmful reduction in the acidity of the medium. 

The addition of mineral acids to hypohalous acids produces a large increase in the rate at which these latter acids halogenate and reaction under these conditions is usually referred to as positive haiogenation which has been subjected to intensive kinetic studies. Whilst there is ample evidence supporting the existence... 

The function of halogen-containing compounds as flame retardants has been explained by the radical trap theory. Liberated halogen acid (HX) competes in the above reactions for those radical species that are critical for flame propagation. 

The monosubstituted adduct offers the ready synthesis of a whole range of monosubstituted adducts (see Scheme 6) it is often possible to isolate in these reactions intermediates that are not readily obtained by alternative methods. Thus, in the reaction with halogen acids to yield the bridged hydrido complexes HOs3(CO)10X, it is possible to identify the intermediate HOs3(CO)uX complex in which the halogen functions as a one-electron donor bonding to only one metal center (158). 

The facility of these decarbonylation reactions is obviously related to the donor capacity of the ligand groups. The halogens follow the variation that may be anticipated for this series. The reactions of Os COlnL with the halogen acids HX (X = Cl, Br, I) involve sequential evolution of carbon monoxide, but their facility increases with the donor capacity of the halogen, Cl < Br < I (157,162). 

Addition reactions at the alkyne bonds are dealt with in the section on alkenylstannanes that are produced. The alkynyl-tin bond is more readily cleaved by both electrophiles and nucleophiles than is the alkenyl- or alkyl-tin bond. Strong electrophiles such as halogens or halogen acids attack at the z/Mzi-position of the triple bond to give a /3-stannyl cation that is stabilized by C-Sn hyperconjugation, but this is followed by cleavage of the C-Sn bond (Equation (83)). 

The addition of halogens and halogen acids to alkenes has been shown to be predominantly trans and where the results do not agree, explanations have been given in terms of steric factors. Dewar has proposed that in all electrophilic addition reactions where a classical carbocation is formed, cis addition is the rule and where there is the preponderance of the trans product, the effect is due to steric factors. 

As esters the alkyl halides are hydrolysed by alkalis to alcohols and salts of halogen acids. They are converted by nascent hydrogen into hydrocarbons, by ammonia into amines, by alkoxides into ethers, by alkali hydrogen sulphides into mercaptans, by potassium cyanide into nitriles, and by sodium acetate into acetic esters. (Formulate these reactions.) The alkyl halides are practically insoluble in water but are, on the other hand, miscible with organic solvents. As a consequence of the great affinity of iodine for silver, the alkyl iodides are almost instantaneously decomposed by aqueous-alcoholic silver nitrate solution, and so yield silver iodide and alcohol. The important method of Ziesel for the quantitative determination of alkyl groups combined in the form of ethers, depends on this property (cf. p. 80). 

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