Формамид

Химические свойства

Formamide is a colorless, viscous liquid. Faint ammonia-like odor.

Использование

Formamide destabilizes nucleic acid duplexes and may be used, typically, at a concentration of 50%, in hybridization protocols requiring lower hybridization temperatures.

Определение

ChEBI: The simplest monocarboxylic acid amide, obtained by formal condensation of formic acid with ammonia. The parent of the class of formaldehydes.

Методы производства

Formamide is produced commercially by two processes (Eberling 1980). In a direct synthesis, ammonia and carbon monoxide react at 100-300 atm and 80-100°C in methanolic sodium methoxide. In the second, a two-stage synthesis, carbon monoxide and methanol form methylformate in the presence of sodium methoxide. The methylformate is treated with liquid or gaseous ammonia at 2-6 atm and 80-100°C.

Общее описание

A colorless liquid with a faint odor of ammonia. Denser than water. Freezing point 36°F.

Реакции воздуха и воды

Hygroscopic. Water soluble.

Профиль реактивности

Formamide is incompatible with strong oxidizers, acids and bases. Sensitive to light. Reacts with water very slowly at room temperature, but rate is accelerated by acids and bases at elevated temperatures. Incompatible with iodine, pyridine and sulfur trioxide. Reacts explosively with furfuryl alcohol, H2O2, Tl(NO3)3.H2O, nitromethane and P2O5. An effective solvent: dissolves casein, glucose, tannins, starch, lignin, polyvinyl alcohol, cellulose acetate, nylon, the chlorides of copper, lead, zinc, tin, cobalt, iron, aluminum and nickel, the acetates of the alkali metals, some inorganic sulfates and nitrates. Attacks copper and brass .

Опасность

Toxic material. Toxic by skin absorption.

Угроза здоровью

Formamide is moderately irritating to the skin and mucous membranes (Windholz 1983).

Сельскохозяйственное использование

Fonnamide is an organic compound containing the amide group -CONH₂. It is made from formic acid or its ester with ammonia. It is also made from ammonia and carbon monoxide.
Formamide is used in making liquid fertilizers for foliar application of nitrogen. For example, a mixture of formamide, urea and ammonium nitrate is used as a solution fertilizer and has a salt-out temperature of 0°C. It contains more than 35% nitrogen, unlike the aqueous formulations of urea, and ammonium nitrate, which have 32 % nitrogen.Formamide is a good solvent for many organic compounds.

Промышленное использование

Formamide is used in the large scale production of formic acid by reaction with inorganic acids, as an intermediate in the chemical industry, as a solvent in the processing of plastics, and as a solvent in felt-tip pens (Eberling 1980).

Профиль безопасности

Poison by skin contact and subcutaneous routes. Moderately toxic by ingestion, intraperitoneal, and intramuscular routes. An irritant to skin, eyes, and mucous membranes. Experimental teratogenic and reproductive effects. An eye irritant. Mutation data reported. Combustible when exposed to heat or flame; can react vigorously with oxidizing materials. Incompatible with 12, pyridine,SO3. When heated to decomposition it emits toxic fumes of NOx. Has exploded while in storage.

Возможный контакт

Formamide is a powerful solvent. It is also used as an intermediate in pharmaceutical manufacture.

Экологическая судьба

If released to air, formamide will exist solely as a vapor in the ambient atmosphere. Vapor-phase formamide will be degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals. The half-life for this reaction in air is estimated to be 8.0 days. If released to soil, formamide is expected to have very high mobility. Volatilization from moist soil surfaces is not expected to be an important fate process. If released into water, formamide is not expected to adsorb to suspended solids and sediment. Several biodegradation screening studies have observed significant biodegradation of formamide, which suggests that biodegradation may be important. Volatilization from water surfaces is not expected to be an important fate process based upon this compound’s estimated Henry’s law constant.

Метаболизм

There are only very few reports on the metabolic fate of formamide in the literature. Halsey (1898) found that formamide gave rise to as much urinary formate in the dog as did formic acid, and assumed complete hydrolysis of the amide in vivo. In a study by Bray et al (1949) the hypothesis was tested that formamide undergoes metabolic hydrolysis in rabbits. Acidic substances were titrated after extraction by ether, before and after hydrolysis of urine samples. The ether-soluble acid determined in hydrolyzed urine was assumed to reflect the amount of formamide excreted unchanged. The difference between the amount of amide administered and the total amount excreted unchanged was considered to represent amide which was metabolically hydrolyzed. After administration of 2-4 g per rabbit orally, 39% of the dose was recovered unchanged using this method. When formamide was incubated with rabbit liver extracts or liver slices, only very little hydrolysis was detected by this method.

Перевозки

UN2810 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.

Методы очистки

Formamide is easily hydrolysed by acids and bases. It also reacts with peroxides, acid halides, acid anhydrides, esters and (on heating) alcohols, while strong dehydrating agents convert it to a nitrile. It is very hygroscopic. Commercial material often contains acids and ammonium formate. Vorhoek [J Am Chem Soc 58 2577 1956] added some bromothymol blue to formamide and then neutralised it with NaOH before heating to 80-90o under reduced pressure to distil off ammonia and water. The amide is again neutralised and the process is repeated until the liquid remained neutral on heating. Sodium formate is added, and the formamide is concentrated under reduced pressure at 80-90o. The distillate is again neutralised and redistilled. It is then fractionally crystallised in the absence of CO2 and water by partial freezing. Formamide (specific conductance 2 x 10-7 ohm-1 cm-1) of low water content is dried by passage through a column of 3A molecular sieves, then deionized by treatment with a mixed-bed ion-exchange resin loaded with H+ and HCONH-ions (using sodium formamide in formamide)[Notley & Spiro J Chem Soc (B) 362 1966]. [Beilstein 2 IV 45.]

Несовместимости

Forms hydrocyanic acid with water solutions. Hygroscopic (absorbs moisture from air). Incompatible with nonoxidizing mineral acids; strong acids; ammonia, cresols, iodine, isocyanates, oleum, phenols, pyr idine, sulfur trioxide; oxidizers, iodine, pyridine. Formamide decomposes on heating @ 180℃ forming ammonia, water, carbon monoxide and hydrogen cyanide. Attacks metals, such as aluminum, iron, copper, brass, lead, and natural rubber. Thermal decomposition may release deadly hydrogen cyanide. Compounds of the carboxyl group react with all bases, both inorganic and organic (i.e., amines) releasing substantial heat, water and a salt that may be harmful. Incompatible with arsenic compounds (releases hydrogen cyanide gas), diazo compounds, dithio carbamates, isocyanates, mercaptans, nitrides, and sulfides (releasing heat, toxic and possibly flammable gases), thiosulfates and dithionites (releasing hydrogen sulfate and oxides of sulfur).

Утилизация отходов

Dissolve in a combustible solvent and dispose by burning in a furnace equipped with an alkali scrubber for the exit gases.