Cyanoethylation

Cyanoethylation of wood meal has been used to impart thermoplasticity to wood (Morita and Sakata, 1986 Hon and San Luis, 1989). Treatment of cyanoethylated wood with a chlorine solution has also been found to improve the solubility of the treated wood in various organic solvents (Morita etal, 1987). Films have been prepared by casting from DMF solution on to glass (Yamawaki etal, 1990). 

Many inorganic and organic compounds possessing labile hydrogen atoms add acrylonitrile readily with the formation of compounds containing a cyancethyl grouping (—CHa. CH2. CN). This reaction is usually known as cyanoethylation  

Typical compounds which undergo cyanoethylation include the following  

Compounds containing one or more —OH or —SH groups, such as water, alcohols, phenols, oximes, hydrogen sulphide and thiols. 

Compounds containing one or more —NH— groups, e.g., ammonia, primary and secondary amines, hydrazines, hydroxylamines and amides. 

Ketones or aldehydes possessing a —CH—, —CH —, or —CH3 group adjacent to the carbonyl group. 

---

The last-named reaction provides an excellent method for the preparation of a-substituted glutaric acids the intermediate alkyl (aryl) -2-cyanoethyl-malonate is both hydrolysed and decarboxylated re ily by boiling with an excess of 48 per cent, hydrobromic acid solution. 

The exchange resins 6nd application in (i) the purification of water (cation-exchange resin to remove salts, followed by anion-exchange resin to remove free mineral acids and carbonic acid), (ii) removal of inorganic impurities from organic substances, (iii) in the partial separation of amino acids, and (iv) as catalysts in organic reactions (e.g., esterification. Section 111,102, and cyanoethylation. Section VI,22). 

A widely used protecting agent is 2-cyanoethanol (- 3-hydroxypropanonitrile, hy-dracrylonitrile), which is condensed with phosphates with the aid of DCC. The 2-cyanoethyl (Ce) group is quantitatively removed as acrylonitrile by treatment with weak bases (H.G. Kho-rana, 1965). 

Because coupling is not always quantitative, the non-reacted terminal deoxynucteoside must be excluded from the following synthesis cycles. Otherwise deletion sequences will render the isolation of the pure final product difficult. Therefore a capping step (step 3) follows, e.g., acetylation with acetic anhydride and N,N-dimethyl-4-pyridinamine (DMAP) in dioxane. Capping times should be as short as possible, especially with 2-cyanoethyl phosphite triesters, which are sensitive to bases such as DMAP. 

Acrylonitrile reacts with the sodium salt of 4.5-dimethvl-A-4-thiazoline-2-thione (73J (R4 = R5 = Me) to yield 3-(2-cyanoethyl)-4.5-dimethyl-A-4-thiazoline-2-thione (74) (R4 = R, = Me) (Scheme 35 (160). Humphlett s studies of this reaction showed that the size of the R4 substituent is a determinant factor for the S versus N ratio (161. 162). If R4 == H, 100% of the N-substituted product (74) is obtained this drops to 50% when R4 = methyl, and only the S-substituted product (75) is obtained when R4 = phenyl. The same trend is observed with various CH2 = CH-X (X = C00CH3. COCH3) reagents (149). The S/N ratio also depends on the electrophilic center for CH2 = CH-X systems thus S-reaction occurs predominantly with acrylonitrile, whereas N-substitution predominates with methvlvinvlketone (149). 

THACRYLIC ACID AND DERIVATIVES] (Vol Id) N-(2-Cyanoethyl)-Nmethylmethacrylamide [7d392-04-d]... 

Small amounts of propionitrile and bis(cyanoethyl) ether are formed as by-products. The hydrogen ions are formed from water at the anode and pass to the cathode through a membrane. The catholyte that is continuously recirculated in the cell consists of a mixture of acrylonitrile, water, and a tetraalkylammonium salt the anolyte is recirculated aqueous sulfuric acid. A quantity of catholyte is continuously removed for recovery of adiponitrile and unreacted acrylonitrile the latter is fed back to the catholyte with fresh acrylonitrile. Oxygen that is produced at the anodes is vented and water is added to the circulating anolyte to replace the water that is lost through electrolysis. The operating temperature of the cell is ca 50—60°C. Current densities are 0.25-1.5 A/cm (see Electrochemical processing). 

N- acetylmethacryl- amide /V-m eth a cry oylm al e- am ic acid methacryloylamido-acetonitrile N- (2-cyanoethyl)meth-acrylamide l-methacrjioylurea... 

N,N- dimethylmeth-acrylamide N,N- diethylmethacryl- amide N- (2-cyanoethyl)-A/-methylmethacrylami de... 

Com and rice starches have been oxidized and subsequently cyanoethylated (97). As molecular size decreases due to degradation during oxidation, the degree of cyanoethylation increases. The derivatized starch shows pseudoplastic flow in water dispersion at higher levels of cyanoethylation the flow is thixotropic. Com and rice starches have been oxidized and subsequently carboxymethylated (98). Such derivatives are superior in the production of textile sizes. Potato starch has been oxidized with neutral aqueous bromine and fully chemically (99) and physically (100) characterized. Amylose is more sensitive to bromine oxidation than amylopectin and oxidation causes a decrease in both gelatinization temperature range and gelatinization enthalpy. 

Reaction of olefin oxides (epoxides) to produce poly(oxyalkylene) ether derivatives is the etherification of polyols of greatest commercial importance. Epoxides used include ethylene oxide, propylene oxide, and epichl orohydrin. The products of oxyalkylation have the same number of hydroxyl groups per mole as the starting polyol. Examples include the poly(oxypropylene) ethers of sorbitol (130) and lactitol (131), usually formed in the presence of an alkaline catalyst such as potassium hydroxide. Reaction of epichl orohydrin and isosorbide leads to the bisglycidyl ether (132). A polysubstituted carboxyethyl ether of mannitol has been obtained by the interaction of mannitol with acrylonitrile followed by hydrolysis of the intermediate cyanoethyl ether (133). 

In a much different approach based on cyanamide, acrylonitrile, and acetonitrile, cyanoacetamidine [56563-07-6] (32) is cyanoethylated and the condensation product [56563-10-1] (33) is dehydrogenated and hydrogenated direcdy to Grewe diamine in the presence of Raney cobalt and ammonia (56). 

---