Aldehydes from formic acid

The common method of naming aldehydes corresponds very closely to that of the related acids (see Carboxylic acids), in that the term aldehyde is added to the base name of the acid. For example, formaldehyde (qv) comes from formic acid, acetaldehyde (qv) from acetic acid, and butyraldehyde (qv) from butyric acid. If the compound contains more than two aldehyde groups, or is cycHc, the name is formed using carbaldehyde to indicate the functionaUty. The lUPAC system of aldehyde nomenclature drops the final e from the name of the parent acycHc hydrocarbon and adds al If two aldehyde functional groups are present, the suffix -dialis used. The prefix formjlis used with polyfunctional compounds. Examples of nomenclature types are shown in Table 1. 

There are, however, numerous organic precendents. The Cannizzaro reaction, in which two equivalents of a nonenolizable aldehyde such as bezaldehyde are reacted with hydroxide to form a primary alcohol and the salt of a carboxylic acid, is thought to involve hydride transfer to one aldehyde carbonyl from the carbonyl-addition product of the other aldehyde and hydroxide. The Leuckart reaction, formation of a tertiary amine from formic acid, a primary amine and either a ketone or an aldehyde, seems to procede via hydride transfer from formate to an iminium ion. And the Meervein-Ponndorf-Verley-Oppenauer reaction, the reversible transfer of hydrogen between ketones and secondary alcohols in the presence of excess aluminum isopropoxide, is almost certainly a hydride-transfer reaction. This latter process is of particular interest to us because it requires a metal, just as GI does. The aluminum acts as a Lewis acid, coordinating the carbonyl oxygen and... 

C12H2ooio,MO,H O. The synthesis of alanine, C H NOS by Strecker from aldehyde ammonia, formic acid, and hydrocyanic acid, and the conversion of alanine into lactic acid by means of nitrous acid, seemed to indicate the formula C H O for lactic acid, and this was confirmed by Wurtz, who obtained it by oxidisihg propylene glycol, at the same time regarding it as dibasic (C = 12, O = 16) ... 

The common name for an aldehyde is derived from the common name of the corresponding carboxylic acid by dropping the word acid and changing the suffix -ic or -oic to -aldehyde. Because we have not yet studied common names for carboxylic acids, we are not in a position to discuss common names for aldehydes. We can, however, illustrate how they are derived by reference to two common names of carboxylic acids with which you are familiar. The name formaldehyde is derived from formic acid, and the name acetaldehyde from acetic acid ... 

Lone pair donation from the hydroxyl oxygen makes the carbonyl group less elec trophilic than that of an aldehyde or ketone The graphic that opened this chapter is an electrostatic potential map of formic acid that shows the most electron rich site to be the oxygen of the carbonyl group and the most electron poor one to be as expected the OH hydrogen... 

Hydrazinopyridazines are easily formylated with formic acid or ethyl formate and acety-lated with acetic anhydride. A-Pyridazinylthiosemicarbazides are obtained from thiocyanates or alkyl- and aryl-isothiocyanates. Hydrazinopyridazines condense with aliphatic and aromatic aldehydes and ketones to give hydrazones. 

Paint and varnish manufacturing Resin manufacturing closed reaction vessel Varnish cooldng-open or closed vessels Solvent thinning Acrolein, other aldehydes and fatty acids (odors), phthalic anhydride (sublimed) Ketones, fatty acids, formic acids, acetic acid, glycerine, acrolein, other aldehydes, phenols and terpenes from tall oils, hydrogen sulfide, alkyl sulfide, butyl mercaptan, and thiofen (odors) Olefins, branched-chain aromatics and ketones (odors), solvents Exhaust systems with scrubbers and fume burners Exhaust system with scrubbers and fume burners close-fitting hoods required for open kettles Exhaust system with fume burners... 

H. Reaction with Formic and Trichloroacetic Acids Enamines derived from aldehydes have been treated with formic acid under the conditions of the Leuckart-Wallach reaction 141) to give saturated tertiary amines 142). The enamine (98) reacts vigorously with formic acid at room temperature to give N-isobutyl morpholine (204). 

The decarbonylation of aromatic aldehydes with sulfuric acid" is the reverse of the Gatterman-Koch reaction (11-16). It has been carried out with trialkyl- and trialkoxybenzaldehydes. The reaction takes place by the ordinary arenium ion mechanism the attacking species is H and the leaving group is HCO, which can lose a proton to give CO or combine with OH from the water solvent to give formic acid." Aromatic aldehydes have also been decarbonylated with basic catalysts." When basic catalysts are used, the mechanism is probably similar to the SeI process of 11-38. See also 14-39. 

Gordon used a household microwave oven for the transfer hydrogenation of benz-aldehyde with (carbonyl)-chlorohydridotris-(triphenylphosphine)ruthenium(II) as catalyst and formic acid as hydrogen donor (Eq. 11.43) [61]. An improvement in the average catalytic activity from 280 to 6700 turnovers h-1 was achieved when the traditional reflux conditions were replaced by microwave heating. 

Figure 5.6 Alcohols, aldehydes, ketones and acids 15, ethylene glycol 16, vinyl alcohol 17, acetaldehyde 18, formaldehyde 19, glyoxal 20, propionaldehyde 21, propionaldehyde 22, acetone 23, ketene 24, formic acid 25, acetic acid 26, methyl formate. (Reproduced from Guillemin et at. 2004 by permission of Elsevier)...

The Cannizzaro reaction is by no means confined to aromatic aldehydes. Formaldehyde undergoes the same change, yielding formic acid and methyl alcohol. That the aliphatic aldehydes from acetaldehyde upwards do not undergo the reaction is due to the fact that the aldol condensation (mentioned above), in virtue of its much greater velocity, takes precedence over the Cannizzaro reaction. 

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