Formic acid, esters, decomposition

Finally, decomposition with water yields the tertiary alcohol. In the case of the esters of formic acid, used in excess, the reaction can be checked at the first stage, and by decomposing the product... 

The simplest or lowest member of the fatly acid series is formic acid, HCOOH. followed by acetic acid, CHiCOOH. propionic acid with three carbons, butyric acid with four carbons, valeric acid with five carbons, and upward to palmitic acid with sixteen carbons, stearic acid with eighteen carbons and melissic acid with thirty carbons. Fatty acids are considered to be the oxidation product of saturated primary alcohols. These acids are stable, being very difficult [with the exception of formic acid) to convert to simpler compounds they easily undergo double decomposition because of the carboxyl group they combine with alcohols to form esters and water they yield halogen-subslitulion products they convert to acid chlorides when reacted with phosphorus pcntachloridc and Iheir acidic qualities decrease as their formula weight increases. 

Diphenyl Malonate and Diphenyl Oxalate. Above 200°C, the half ester of malonic acid decomposes to carbon dioxide and an ester of acetic acid, and the half ester of oxalic acid decomposes to carbon dioxide and an ester of formic acid. Diphenyl malonate and diphenyl oxalate are chain extenders that decrease the terminal PET COOH content by these decomposition reactions. 

Esters of formic acid (Expt 5.143) are most simply prepared from the alcohol and an excess of formic acid, which, being a comparatively strong acid, does not require the use of added mineral acid to catalyse the esterification reaction. Sulphuric acid in any case should not be added since it causes the decomposition of formic acid to carbon monoxide. 

SAFETY PROFILE Moderately toxic by ingestion. Mildly toxic by inhalation. Human systemic effects by inhalation muscle contractions and spasticity, conjunctiva irritation, and unspecified respiratory changes. An irritant and narcotic in high concentrations. See also ESTERS, n-BUTYL ALCOHOL, and FORMIC ACID. Dangerous fire hazard when exposed to heat or flame. To fight fire, use alcohol foam, foam, CO2, dry chemical. Incompatible with oxidizing materials. When heated to decomposition it emits acrid and irritating fumes. 

SAFETY PROFILE Mildly toxic by ingestion. A human skin irritant. Combustible liquid. When heated to decomposition it emits acrid smoke and irritating fumes. See also ESTERS and FORMIC ACID. 

FORMIC ACID, METHYL ESTER (107-31-3) Forms explosive mixture with air (flash point —25°F/—32°C). Reacts with water, causing slow decomposition. Reacts violently with strong oxidizers. Incompatible with strong acids, alkalis, nitrates. Attacks some plastics and coatings. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

Reduction of the acid stage to the aldehyde 2S8 or 290 is possible by catalytic hydrogenation of the corresponding a-ketophosphonic esters [615] and subsequent termal [617] or alkaline [618] decomposition of the a-hydroxyphosphonic esters. Another possibility is the selective reduction of the ester with deactivated aluminum-hydrides [619] or catalytic reduction of the acid chloride [620]. On a bench scale, reduction of the bromofluoro benzonitrile with Raney nickel in formic acid [621] is particularly advisable. 

Z-Eburnamonine (XXXVI) has been produced by other reactions of vincamine. Oxidation of vincaminic acid (XL R = H) by means of ammoniacal silver nitrate was one way, and periodic acid fission of vincaminol was another (16). A different group of workers, who had probably attempted to prepare vincaminol by lithium aluminum hydride reduction of vincamine, obtained instead Z-ebumamonine in excellent yield (18). This has been rationalized as illustrated (partial formulas) by analogy with the base-induced decomposition of formic esters to carbon monoxide and alkoxide ion ... 

Base-catalysed loss of carbon monoxide has occasionally been observed as well as the acid-catalysed decarbonylation. Such reactions include the decomposition of formic esters to carbon monoxide and alcohols under the influence of alkali alkoxides,61 e.g. ... 

The Michaelis-Arbuzov reaction is unable to provide the simplest of the acylphospho-nic acids, namely (oxomethyl)phosphonic acid, the diethyl ester of which, 493, has been obtained from triethyl phosphite and formic-acetic anhydride at -10 °C at a higher temperature, decomposition sets in with the liberation of CO and formation of diethyl hydrogenphosphonate. Ensuing reactions lead ultimately to 494 ... 

---