Search results
Results From The WOW.Com Content Network
Phenylhydrazine was the first hydrazine derivative characterized, reported by Hermann Emil Fischer in 1875. [7] [8] He prepared it by reduction of a phenyl diazonium salt using sulfite salts. Fischer used phenylhydrazine to characterize sugars via formation of hydrazones known as osazones with the sugar aldehyde. He also demonstrated in this ...
Since the reaction requires a free carbonyl group, only "reducing sugars" participate. Sucrose, which is nonreducing, does not form an osazone. A typical reaction showing the formation of an osazone. D-glucose reacts with phenylhydrazine to give glucosazone. The same product is obtained from fructose and mannose.
Phenylhydrazine and 2,4-dinitrophenylhydrazine had been used historically in analytical chemistry to detect and identify compounds with carbonyl groups. Phenylhydrazine was used to study the structure of carbohydrates, because the reaction of the sugar's aldehyde groups lead to well crystallizing phenylhydrazones or osazones.
Hydrazones can also be synthesized by the Japp–Klingemann reaction via β-keto acids or β-keto-esters and aryl diazonium salts. Hydrazones are converted to azines when used in the preparation of 3,5-disubstituted 1 H - pyrazoles , [ 12 ] a reaction also well known using hydrazine hydrate .
Reaction 3: 4 NH 3 + N 2 H 4 → 3 N 2 + 8 H 2. The first two reactions are extremely exothermic (the catalyst chamber can reach 800 °C in a matter of milliseconds, [28]) and they produce large volumes of hot gas from a small volume of liquid, [29] making hydrazine a fairly efficient thruster propellant with a vacuum specific impulse of about ...
The Fischer indole synthesis is a chemical reaction that produces the aromatic heterocycle indole from a (substituted) phenylhydrazine and an aldehyde or ketone under acidic conditions. [1] [2] The reaction was discovered in 1883 by Emil Fischer. Today antimigraine drugs of the triptan class are often synthesized by this method. The Fischer ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Food physical chemistry is considered to be a branch of Food chemistry [1] [2] concerned with the study of both physical and chemical interactions in foods in terms of physical and chemical principles applied to food systems, as well as the applications of physical/chemical techniques and instrumentation for the study of foods.