Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Aldehydes, halogenation hydration

Examples are given of common operations such as absorption of ammonia to make fertihzers and of carbon dioxide to make soda ash. Also of recoveiy of phosphine from offgases of phosphorous plants recoveiy of HE oxidation, halogenation, and hydrogenation of various organics hydration of olefins to alcohols oxo reaction for higher aldehydes and alcohols ozonolysis of oleic acid absorption of carbon monoxide to make sodium formate alkylation of acetic acid with isobutylene to make teti-h ty acetate, absorption of olefins to make various products HCl and HBr plus higher alcohols to make alkyl hahdes and so on. [Pg.2110]

The hydration reaction just described is typical of what happens when an aldehyde ot ketone is treated with a nucleophile of the type H-Y, where the Y atom is electronegative and can stabilize a negative charge (oxygen, halogen, or sulfur, for instance). In such reactions, the nucleophilic addition is reversible, with the equilibrium generally favoring the carbonyl reactant rather than the tetrahedral addition product. In other words, treatment of an aldehyde or... [Pg.706]

Studies of aliphatic a-haloaldehydes in water-dioxane have shown that the electrochemical behavior of these compounds is affected by the equilibrium between the hydrated and unhydrated forms of the aldehyde [92]. Each carbon-halogen bond is broken in a two-electron, one-proton process, and the resulting nonhalogenated aldehyde undergoes reduction at a more negative potential [93]. [Pg.227]

The possibility of hydrogenating halogenated aldehydes and ketones by means of phytochemical reduction was tested as early as 1913 the successful results in this field clearly demonstrate the importance of this method. Lintner and Ltters found that chloral hydrate can be converted to trichloroethyl alcohol. This transformation takes place so easily that, according to Willstatter and Duisberg, it can be used under favorable experimental conditions as a convenient method for the preparation of the halogenated alcohol. The tribromoethyl alcohol may be prepared in an analogous manner. [Pg.81]

Acyl-substituted imidazoles have distinctive UV and IR spectra, and can exist as hydrates in solution, e.g. imidazole-2-carbaldehyde. The aldehyde group is sufficiently electron withdrawing to assist nucleophilic displacement of an adjacent halogen atom. The normal aldehyde derivatives such as oximes, acetals and hydrazones can be formed, and the kinetics of oxime formation with the 4-carbaldehyde have been studied. The tautomeric ratio (zwitterion uncharged aldehyde form) of 1-substituted imidazole- and benzimidazole-2-aldoximes rises in parallel with an increase in basicity of the parent molecule (73CHE1074). These compounds have been shown by NMR studies to adopt the syn configuration. With hydrazine hydrate, imidazole-4,5-dicarbaldehydes give imidazo[4,5-d]pyridazines (208 Scheme 110). [Pg.436]

Passerini, M. The isonitriies. III. Reaction with halogen aldehyde hydrates. Gazz. Chim. Itai. 1922, 52, 432-435. [Pg.645]

Near infrared studies on a solution of chloral hydrate show the existence of a labile equilibrium between the gem-diol and a dimolecular 1 1 complex of the aldehyde and water. It is thought that the gem-diol structure results from the electronic effect of the halogens transmitted through the molecule, rather than from intramolecular hydrogen bonding between the halogens and the hydroxyl hydrogens. [Pg.89]


See other pages where Aldehydes, halogenation hydration is mentioned: [Pg.124]    [Pg.646]    [Pg.40]    [Pg.472]    [Pg.764]    [Pg.706]    [Pg.766]    [Pg.786]    [Pg.2130]    [Pg.53]    [Pg.264]    [Pg.112]    [Pg.224]    [Pg.553]    [Pg.642]    [Pg.891]    [Pg.956]    [Pg.1004]    [Pg.1077]    [Pg.766]    [Pg.2116]    [Pg.315]    [Pg.104]    [Pg.574]    [Pg.38]    [Pg.472]    [Pg.1042]    [Pg.63]    [Pg.640]    [Pg.650]   
See also in sourсe #XX -- [ Pg.1262 ]




SEARCH



Aldehyde hydrate

Aldehydes halogenation

Aldehydes hydrated

Aldehydes hydration

Halogen aldehydes

Halogenated aldehydes

© 2024 chempedia.info