Dihydrogen reactions

Catalyst Dihydrogen Reaction Order n-Heptane Reaction Order... 

Characterization of oxygen-treated carbides of molybdenum and tungsten for /i-hexane-dihydrogen reactions... 

Direct titrations are commonly carried out using disodium dihydrogen ethylenediaminetetraace-tate, NajHjY, which is available in pure form. The reaction of the chelon with the indicator must be rapid for a practical, direct titration. Where it is slow, heating of the titration medium is often expedient, or another indicator is employed. 

Hexafluoroarsenic acid [17068-85-8] can be prepared by the reaction of arsenic acid with hydrofluoric acid or calcium fluorosulfate (29) and with alkaH or alkaline-earth metal fluorides or fluorosulfonates (18). The hexafluoroarsenates can be prepared directly from arsenates and hydrofluoric acid, or by neutrali2ation of HAsF. The reaction of 48% HF with potassium dihydrogen arsenate(V), KH2ASO4, gives potassium hydroxypentafluoroarsenate(V)... 

Electronegatively substituted acetylenes, such as dimethyl acetylenedicar-boxylate, do not react under normal conditions but will add the elements of hydrogen fluoride by reaction with fluoride ion (e g, CsF or tetraalkylammonium dihydrogen trifluoride) and a proton source under phase-transfer conditions [49, 50] (equation 8)... 

Deoxy-D-jcylo hexose 6-(dihydrogen phosphate) (21) has also been synthesized (2) the reaction sequence makes use of 3-deoxy l 2,5 6-di-O-isopropylidene D-galactofuranose (16), a compound that can be easily prepared from D-glucose (2, 60). The mono-isopropylidene derivative (17) formed by partial hydrolysis of the di-ketal is converted into the 6-tosylate (18) by reaction with one molar equivalent of p-toluenesulfonyl chloride. From this the epoxide (19) is formed by reaction with sodium methoxide. Treatment of the anhydro sugar with an aqueous solution of disodium hydrogen phosphate (26) leads to the 6-phosphate (20)... 

A more complicated reaction sequence has been used by Ukita and Nagasawa (59) in their synthesis of 2-deoxy D-ribose 5-phosphate (2-deoxy D-erythro-pentose 5-(dihydrogen phosphate)), (29). They phosphorylated a mixture of the anomeric methyl deoxyribofuranosides (24)... 

The rate of the reaction in various buffer solutions, covering the pH range 4-8, was determined, and in hydrogen phosphate-dihydrogen phosphate buffers the rate at constant pH decreased as the concentration of dihydrogen phosphate increased. Similarly, with acetic acid-acetate and phosphoric acid-dihydrogen phosphate buffers the rate was inversely dependent upon the concentration of the molecular acid in addition, with the latter buffer, the kinetic plots showed an unexplained departure from linearity after 50 % reaction. 

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