Reactive hydrogen

Secondary and pnmary alcohols do not react with HCl at rates fast enough to make the preparation of the conespondmg alkyl chlorides a method of practical value There fore the more reactive hydrogen halide HBr is used even then elevated temperatures are required to increase the rate of reaction... 

Toluene diisocyanate Midget impinger 15 ml Marcali solution 1 25 95 Diazotlzation and coupling reaction Materials containing reactive hydrogen attached to oxygen (phenol) certain other diamines... 

Interesting amine flexibilisers have also been described. These materials are made by cyanoethylation of amine hardeners such as diethylenetriamine, to such an extent that only two reactive hydrogens remain and the material is only difunctional, e.g. Figure 26.21. 

The weight in grams to provide one reactive hydrogen atom for every epoxide group in lOOg of liquid epoxide resin of epoxide equivalent 190. 

The best preparative results from autoxidation are encountered when only one relatively reactive hydrogen is available for abstraction. The oxidation of isopropylbenzene (cumene) is carried out on an industrial scale, with the ultimate products being acetone and phenol ... 

For the acetoxy radical, the for decarboxylation is about 6.5 kcal/mol and the rate is about 10 s at 60°C and 10 s at —80°C. Thus, only very rapid reactions can compete with decarboxylation. As would be expected because of the lower stability of aryl radicals, the rates of decarboxylation of aroyloxy radicals are slower. The rate for p-methoxybenzoyloxy radical has been determined to be 3 x 10 s near room temperature. Hydrogen donation by very reactive hydrogen-atom donors such as triethylsilane can compete with decarboxylation at moderate temperatures. 

Rhoeadine crystallises from a mixture of chloroform and ether, sublimes at 215-25" /0-02 mm., and then melts at 256-57-5° (vac.), and has [a] / ° -f 232° (CHClj). According to Awe it has m.p. 272-4° (Kofler s micro-apparatus), and [a]] ° -f 243° (CHClj). A crystalline liydriodide, B. HI. 2H2O, was prepared by the addition of potassium iodide to a solution of the alkaloid in acetic acid. Rhoeadine contains one methoxyl group and a dioxymethylene group, but no reactive hydrogen (Zerewitinoff). 

Per reactive hydrogen relative to toluene as standard. 6 AtWC. 

In the single-stage production of polyurethanes, di-, tri-, or polyisocyanates are mixed directly with molecules containing two or more reactive hydrogen atoms, such as diols, diamines, and dicarboxylic acids. We typically increase the reaction rate by adding amine or organotin based catalysts. The reaction normally occurs rapidly, evolving much heat. In order to ensure... 

Polymeric molecules contain reactive hydrogen sites in the form of alcohols and carboxylic acids. The reaction sequence, alcohol plus anhydride and acid plus oxirane, results in an increase of one in the degree of polymerization if the oxirane is DGEBA. Polymeric species also supply oxiranes via the pendant R. These reactions are generalized by the notation ... 

The sum is invariant and equals the cumulative number of reactive hydrogen sites present. 

Alkyl Radical, R, in Poly (R-Methacrylate) Reactive Hydrogen on Alkyl Carbon Atom No. Intrinsic Viscosity in MEK, 23°C Hours to Attain 50% Insolubility... 

Chemically it behaves like the other bromine fluorides, but is more reactive. Hydrogen... 

The hydrogen set free can add to unsaturated compounds these reactions occur in the lower reaches of the Titanian atmosphere. Hydrogen cannot escape from the upper atmosphere before it reacts. The authors suggest a catalytic scheme in which reactive hydrogen atoms are converted into molecular hydrogen (H2) without a net loss of unsaturated compound (here C4H2) ... 

The metallic component of HCK catalysts provides hydrogenation, dehydrogenation, hydrogenolysis, and isomerization. The number and nature of reactive hydrogen species created by the interaction of a bifunctional catalyst with hydrogen is not well understood [103], on the other hand, neither the action of those species on the catalytic sites is understood. The main limitation in this understanding is the dynamic character of the interaction however, now that in situ characterization techniques are becoming available, research would soon defeat the limitations. 

Jr Carbene Formation Reactive Hydrogen Containing Compound Or Insertion with Covalent Bond Formation (Reaction 56)... 

This equation shows that the most relevant computational information on the drug-receptor complex is encoded both in reactivity (hydrogen bond donor propensity) and in shape descriptors. 

Keeping items (1) to (4) in mind we may next envisage a potentially negative centre on the enzyme and also a closely located centre containing a reactive hydrogen (perhaps an OH or a NH group) (see fig. 19 (a)). 

The production of aniline from nitrobenzene proceeds in such a way that the reactive hydrogen is added to the nitro-group, the oxygen is eliminated as water, and finally hydrogen is again added on. The process is not a simple one and involves a series of intermediate stages ... 

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