Cyanacetic acid

Citral also forms a crystalline derivative with cyanacetic acid, citrylidene-cyanacetic acid of the formula—... 

It is obtained hy mixing 1 molecule of cyanacetic acid, 1 molecule oh citral, and 2 molecules of caustic soda. The reaction liquid is extracted with ether, in order to remove non-aldehydes, and the clear liquid acidified with acetic acid. The separated acid is dissolved in benzene and precipitated hy petroleum ether when it forms yellow crystals, melting at 122° in the case of a-citral, and at 94° to 95° in the case of -citral. 

It also forms citronellylidene-cyanacetic acid, melting at 137° to 138°. It forms additive compounds with sodium bisulphite, which are similar in characters to the corresponding citral compounds. 

Dipropyl acetic acid or valproic acid may be prepared the next way. Propylbromide is mixed with cyanacetic acid in the presence of sodium ethylate, made from absolute ethanol and sodium. By that prepared a,a-dipropylcyanacetic acid ethyl ester is saponified with equimolecular amounts of NaOH to give dipropylacetonitril. The desired dipropylacetic acid is produced by saponification of dipropylacetonitryl with aquatic NaOH. It is colorless liquid. BP 219°-220°C. 

The crude ester obtained in this way was then treated with a solution of 7.5 g of flaked sodium hydroxide in 67.5 ml of water. The mixture was introduced into a 250 ml spherical flask, equipped with a condenser, and then the reaction medium was slowly brought to 60°-70°C. This temperature was maintained for 3 hours, whereafter the mixture was cooled to about 50°C and the ethanol which had formed and the residue of n-propanol were eliminated under a pressure of 70 mm Hg. The solution thus obtained was cooled to 20°C and acidified, while stirring, by addition of 26.25 g of 36% hydrochloric acid. During this operation, the temperature of the reaction medium was kept below 40°C by cooling. Stirring was continued for 30 minutes, whereafter the mixture was left standing for 30 minutes. The oily layer of di-n-propyl cyanacetic acid was decanted and the aqueous phase extracted with 35 ml of toluene. The extract in toluene was then added to the decanted di-n-propyl cyanacetic acid, whereafter the solution in toluene was washed, in a separation funnel, with a solution of 1.5 g of sodium chloride in 14 ml of water. The toluenic phase was decanted and the toluene distilled under atmospheric pressure. 

Using this procedure, 25 g of crude di-n-propyl cyanacetic acid were obtained, (b) Di-n-propyl acetonitrile... 

Finally, mention may be made of two further syntheses, which employ as crucial stages the condensation of iV-acetyl-5-benzyloxyindoxyl (112) or 5-methoxyisatin (113) with cyanacetic acid to give the intermediates XVI and XVII, respectively these were then converted into 5-hydroxy -tryptamine by standard procedures. 

Volume of the cyanacetic acid solution and concentrations ( z H and Cg. connected by the equation... 

Monomers have been prepared in benzene solvent by Knoevanagel reaction between 4-vinyl benzaldehyde and malonic derivatives at room temperature, by use of two catalysts chosen according to the nature of compounds (Table I). For carboxylic acids as malonic or cyanacetic acids piperidine can be used for esters as ethylmalo-nate or ethyl cyanacetate piperidinium benzoate is prefered. 

The carboxyl group thus formed is then acted on in the same way as the carboxyl group of cyanacetic acid abovej with the formation of an ester ... 

CYANACETIC ACID (372-09-8) Combustible solid (flash point 226°F/107°C cc). Dust or powder may form explosive mixture with air. Reacts with water, forming a medium-strong acid solution. Incompatible with oxidizers, strong acids, alkalis, reducing agents, furfuryl alcohol. Aqueous solution is incompatible with sulfuric acid, alkalis, ammonia, aliphatic amines, alkanolamines, alkylene oxides, amides, epichlorohydrin, organic anhydrides, isocyanates, vinyl acetate. Attacks metals in the presence of moisture. 

Synonyms Cyanacetic Acid Malonic Mononitrile Chemical Formula CNCHjCOOH (ii) Observable Characteristics— Physical State (as normally shipped) Solid Color. Wliite Odor Data not available (iii) Physical and Chemical Properties — Physical State at 15 C and I atm. Solid Molecular Weight 85.06 Boiling Point at 1 atm. Not pertinent (decomposes) Freezing Point 151. 66. 339 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity > 1.1 at 20 C (solid) Vapor (Gas) Density Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat of Vaporization Not pertinent Heat of Combustion ... 

A process depending on the use of cyanacetic acid was proposed by the author some years s o, which depends on the condensation of cyancMjetic acid with citral in alkaline solution, according to the following equation —... 

---