Hydrogen reaction with chlorine

As usual, this hypothesis is associated with the names of Bodenstein and Semenov. The latter introduced a concept of partial quasi-stationarity realized for some intermediates. Christiansen described the history of the problem as follows [36] "... the first who applied this theory was S. Chapman and half the year later Bodenstein referred to it in his paper devoted to hydrogen reaction with chlorine. His efforts to confirm his viewpoint were so energetic that this theory is quite naturally associated with his name . 

The reaction with fluorine occurs spontaneously and explosively, even in the dark at low temperatures. This hydrogen—fluorine reaction is of interest in rocket propellant systems (99—102) (see Explosives and propellants, propellants). The reactions with chlorine and bromine are radical-chain reactions initiated by heat or radiation (103—105). The hydrogen-iodine reaction can be carried out thermally or catalyticaHy (106). 

Disilenes readily add halogens14,66 and active hydrogen compounds (HX), such as hydrogen halides,63,66 alcohols, and water,27 63 as well as hydride reagents, such as tin hydride and lithium aluminum hydride.66 These reactions are summarized in Scheme 9. The reaction of the stereo-isomeric disilene (E)-3 with hydrogen chloride and alcohols led to a mixture of E- and Z-isomers, but the reaction with chlorine gave only one of the two possible stereoisomers, thus indicating that the former two reactions proceed stepwise while the latter occurs without Si—Si rotation. 

The chemiluminescent reaction with chlorine dioxide provides a highly sensitive and highly selective method for only two sulfur compounds, hydrogen sulfide and methane thiol [81]. As in the flame photometric detector (FPD), discussed below, atomic sulfur emission, S2(B3S -> ) is monitored in the wave-... 

Before the availability of high-purity lanthanide metals, the most popular starting material was the oxide, readily available pure. Because of their high stability, the oxides cannot readily be converted into the respective trihalides simply by reaction with chlorine or hydrogen chloride as oxochlorides are formed nevertheless, Templeton and Carter (45) have prepared pure trichlorides using this method. 

There is a marked difference in chemical reactivity between bridging and terminal hydrogens. Terminally bonded hydrogens readily react in a similar manner to that observed for mononuclear hydrides. Thus reactions with chlorinated hydrocarbons such as carbon tetrachloride yield the chloro cluster complexes and chloroform. In contrast, bridging hydrides are stable and may be studied in chlorinated sol-... 

Combination of the Hantzsch ester mediated transfer hydrogenation together with chlorine (116) or fluorine (117) electrophiles allows for the formal addition of HCl or HF aaoss a double bond in a catalytic asymmetric manner (Scheme 48) [178], Within this paper the reactions were further refined by the use of two cycle-specific secondary amines which effectively operated independently within the same reaction mixture. Impressively, this allowed access to either diastereoisomer of the product depending upon the absolute configuration of the catalyst used in the second step of the sequence. 

Horn, A. B., J. R. Sodeau, T. B. Roddis, and N. A. Williams, Mechanism of the Heterogeneous Reaction of Hydrogen Chloride with Chlorine Nitrate and Hypochlorous Acid on Water Ice, J. Phys. Chem. A, 102, 6107-6120(1998). 

Syntheses of 5-halogenotetrazoles from metallic derivatives have met with mixed fortunes. Lithiation of 1-methyltetrazole followed by reaction at -60°C with bromine, iodine, or cyanogen bromide gave the 5-bromo and 5-iodo compounds in 36-55% yields (71CJC2139). 1,2-Disubstituted tetrazolium tetraphenylborates were lithiated in the 5-position, but subsequent reaction with chlorine or bromine failed to trap the anion. Instead, oxidation produced a radical cation, which abstracted a hydrogen atom from the solvent [91 AG(E)1162]. 

On reaction with chlorine, hydrogen cyanide gives cyanogen chlorides, forming a trimer—cyanuric chloride (XII). The latter is a liquid with a melting point of 146°C and a boiling point of 196°C. Next, cyanuric triazide (XI) is obtained by the action of sodium azide in an aqueous solution, at room temperature on compound (XII). 

A hydrogen atom on the carbon atom between the carbonyl and the dithiole ring can be substituted by a nitroso group by reaction with nitrous acid in acetic acid at 5°C.50 Sulfury] chloride can also replace this hydrogen atom with chlorine.26 It is also replaced on Vilsmeier-Haack formylation of a (5-aryl-l,2-dithiol-3-ylidene)aceto-phenone.39... 

The small arrows in the above structures represent the shift of electron density toward the chlorine atoms. The effect of substituting a hydrogen atom with chlorine diminishes as the chlorine gets farther and farther from the site of reaction thus, C1CH2CH2CH2C00H is almost the same strength as CH3CH2CH2COOH. 

It is attacked by fluorine but there is no reaction with dry hydrogen fluoride, and only a slow reaction with hydrofluoric acid. Reaction with chlorine produces molybdenum pentachloride. Heating in hydrogen reduces the disulphide directly to molybdenum metal. 

Bulk aluminum may undergo the following dangerous interactions exothermic reaction with butanol, methanol, 2-propanol, or other alcohols, sodium hydroxide to release explosive hydrogen gas. Reaction with diborane forms pyrophoric product. Ignition on contact with niobium oxide + sulfur. Explosive reaction with molten metal oxides, oxosalts (nitrates, sulfates), sulfides, and sodium carbonate. Reaction with arsenic trioxide + sodium arsenate + sodium hydroxide produces the toxic arsine gas. Violent reaction with chlorine trifluoride, Incandescent reaction with formic acid. Potentially violent alloy formation with palladium, platinum at mp of Al, 600°C. Vigorous dissolution reaction in... 

Dichlorotetrafluoroethane is prepared by the reaction of hydrogen fluoride with chlorine and perchloroethylene in the presence of a suitable catalyst such as polyvalent antimony. 

WO2 dissolves in warm, concenhated mineral acids and in boiling, concentrated alkali hydroxide solutions. It dissolves rapidly in diluted and cone. H2O2. Nitric acid oxidizes it to WO3. About the behavior with respect to hydrogen, see Chapter 3. Higher oxides are formed with oxygen at elevated temperature. Reaction with chlorine leads to the formation of WOCI4 and WO2CI2, while with bromine and iodine only the dioxodihalides are formed. 

In contrast to this imide-based synthesis, amides of the type RC(0)NH2 are decarbonylated to primary amines (RNH2) with chlorine in the presence of base. This process, often called the Hofmann reaction, involves an intermediate isocyanate (R-N = C = 0) (Fieser and Fieser, 1961 Sandler and Karo, 1983). Aromatic oximes, lacking an a-hydrogen, react with chlorine to form intermediates that are converted to nitrile Af-oxides with base. (Nitrile N-oxides are highly reactive species.)... 

In the second, reaction with chlorine or bromine causes one of the hydrogen substituents of an alkane to be replaced by halogen. 

Fig. 4. Relative rates of reaction of the isotopic hydrogen molecules with chlorine atoms as a function of temperature. Solid lines calculated from the Wheeler, Topley, and Eyring potential for H,C1.

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