Cyanohydrins acetone cyanohydrin

Cyanohydrins, Acetone cyanohydrin H N-CN (C,H,kN-CN Nitrosobenzene Nitrosodimethylaniline Isonitrosocyanoacetic esters... 

Acetobacter suboxydans, Streptococcus faecalis RCN CChCN CeH CN Adiponitrile (NC)2C = C(CN)2 Cyanohydrins, Acetone cyanohydrin H2N-CN (C2Hs)2N-CN Azodicarboxamide Azodiisobutyronitrile Nitrosobenzene Nitrosodimethylaniline Isonitrosocyanoacetic esters... 

Cyanohydrins, Acetone cyanohydrin Nitrosohenzene Nitrosodimethylaniline Isonitrosocyanoacetic esters... 

CH =C(CH3)C02Me. Colourless liquid b.p. lOO C. Manufactured by healing acetone cyanohydrin with methanol and sulphuric acid. It is usually supplied containing dissolved polymerization inhibitor, on removal of which it is readily polymerized to a glass-like polymer. See acrylate resins. 

Equip a 1-litre three-necked flask with a mechanical stirrer, a separatory funnel and a thermometer. Place a solution of 47 g. of sodium cyanide (or 62 g. of potassium cyanide) in 200 ml. of water in the flask, and introduce 58 g. (73-5 ml.) of pure acetone. Add slowly from the separatory fumiel, with constant stirring, 334 g. (275 ml.) of 30 per cent, sulphuric acid by weight. Do not allow the temperature to rise above 15-20° add crushed ice, if necessary, to the mixture by momentarily removing the thermometer. After all the acid has been added continue the stirring for 15 minutes. Extract the reaction mixture with three 50 ml. portions of ether, dry the ethereal extracts with anhydrous sodium or magnesium sulphate, remove most of the ether on a water bath and distil the residue rapidly under diminished pressure. The acetone cyanohydrin passes over at 80-82°/15 mm. The yield is 62 g. 

Mix 42 5 g. of acetone cyanohydrin (Section 111,75) and 75 g. of freshly powdered ammonium carbonate in a small beaker, warm the mixture on a water bath FUME CUPBOARD) and stir with a thermometer. Gentle action commences at 50° and continues during about 3 hours at 70-80°. To complete the reaction, raise the temperature to 90° and maintain it at this point until the mixture is quiescent (ca. 30 minutes). The colourless (or pale yellow) residue solidifies on coohng. Dissolve it in 60 ml. of hot water, digest with a little decolourising carbon, and filter rapidly through a pre-heated Buchner funnel. Evaporate the filtrate on a hot plate until crystals appear on the surface of the liquid, and then cool in ice. Filter off the white crystals with suction, drain well, and then wash twice with 4 ml. portions of ether this crop of crystals of dimethylhydantoin is almost pure and melts at 176°. Concentrate the mother liquor to the crj staUisation point, cool in ice, and collect the... 

Methyl methacrylate is obtained commercially from acetone cyanohydrin HCN CH.OH,... 

The action of sulphuric acid alone upon acetone cyanohydrin affords a-methylacrylic acid. The methyl methacrylate polymers are the nearest approach to an organic glass so far developed, and are marketed as Perspex (sheet or rod) or Dialcon (powder) in Great Britain and as Plexiglass and Luciie in the U.S.A. They are readily depolymerised to the monomers upon distillation. The constitution of methyl methacrylate polymer has been given as ... 

Out first example is 2-hydroxy-2-methyl-3-octanone. 3-Octanone can be purchased, but it would be difficult to differentiate the two activated methylene groups in alkylation and oxidation reactions. Usual syntheses of acyloins are based upon addition of terminal alkynes to ketones (disconnection 1 see p. 52). For syntheses of unsymmetrical 1,2-difunctional compounds it is often advisable to look also for reactive starting materials, which do already contain the right substitution pattern. In the present case it turns out that 3-hydroxy-3-methyl-2-butanone is an inexpensive commercial product. This molecule dictates disconnection 3. Another practical synthesis starts with acetone cyanohydrin and pentylmagnesium bromide (disconnection 2). Many 1,2-difunctional compounds are accessible via oxidation of C—C multiple bonds. In this case the target molecule may be obtained by simple permanganate oxidation of 2-methyl-2-octene, which may be synthesized by Wittig reaction (disconnection 1). 

Compounds with active hydrogen add to the carbonyl group of acetone, often followed by the condensation of another molecule of the addend or loss of water. Hydrogen sulfide forms hexamethyl-l,3,5-trithiane probably through the transitory intermediate thioacetone which readily trimerizes. Hydrogen cyanide forms acetone cyanohydrin [75-86-5] (CH2)2C(OH)CN, which is further processed to methacrylates. Ammonia and hydrogen cyanide give (CH2)2C(NH2)CN [19355-69-2] ix.orn. 6<55i the widely used polymerization initiator, azobisisobutyronitrile [78-67-1] is made (4). 

World consumption data by end use in 1987 are shown in Table 8 (39). Solvent appHcations account for the largest use of acetone worldwide, followed by production of acetone cyanohydrin for conversion to methacrylates. Aldol chemicals are derivatives of acetone used mainly as solvents (40). 

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Selected physical properties of various methacrylate esters, amides, and derivatives are given in Tables 1—4. Tables 3 and 4 describe more commercially available methacrylic acid derivatives. A2eotrope data for MMA are shown in Table 5 (8). The solubiUty of MMA in water at 25°C is 1.5%. Water solubiUty of longer alkyl methacrylates ranges from slight to insoluble. Some functionalized esters such as 2-dimethylaniinoethyl methacrylate are miscible and/or hydrolyze. The solubiUty of 2-hydroxypropyl methacrylate in water at 25°C is 13%. Vapor—Hquid equiUbrium (VLE) data have been pubHshed on methanol, methyl methacrylate, and methacrylic acid pairs (9), as have solubiUty data for this ternary system (10). VLE data are also available for methyl methacrylate, methacrylic acid, methyl a-hydroxyisobutyrate, methanol, and water, which are the critical components obtained in the commercially important acetone cyanohydrin route to methyl methacrylate (11). 

Until 1982, almost all methyl methacrylate produced woddwide was derived from the acetone cyanohydrin (C-3) process. In 1982, Nippon Shokubai Kagaku Kogyo Company introduced an isobutylene-based (C-4) process, which was quickly followed by Mitsubishi Rayon Company in 1983 (66). Japan Methacryhc Monomer Company, a joint venture of Nippon Shokubai and Sumitomo Chemical Company, introduced a C-4-based plant in 1984 (67). Isobutylene processes are less economically attractive in the United States where isobutylene finds use in the synthesis of methyl /i / butyl ether, a pollution-reducing gasoline additive. BASF began operation of an ethylene-based (C-2) plant in Ludwigshafen, Germany, in 1990, but favorable economics appear to be limited to conditions unique to that site. 

Considerable research is currendy directed toward development of novel technologies that may present economic advantages with respect to the conventional acetone cyanohydrin (ACH) route. Mitsubishi Gas Chemical Co. has developed and patented a modified acetone cyanohydrin-based route... 

Mitsubishi Gas Chemical Company Process. The commercial MMA manufacturing process based on sulfuric acid and acetone cyanohydrin suffers from the large quantities of ammonium sulfate produced. Because ammonium sulfate has only low value as fertili2er, regeneration of sulfuric acid from ammonium sulfate [7783-20-2] is required. Despite the drawbacks of using sulfuric acid, this technology is stiU the most widely practiced... 

ACH = acetone cyanohydrin C-4 = tert-butyl alcohol- isobutylene C-2 = ethylene. ... 

The handling of toxic materials and disposal of ammonium bisulfate have led to the development of alternative methods to produce this acid and the methyl ester. There are two technologies for production from isobutylene now available ammoxidation to methyl methacrylate (the Sohio process), which is then solvolyzed, similar to acetone cyanohydrin, to methyl methacrylate and direct oxidation of isobutylene in two stages via methacrolein [78-85-3] to methacryhc acid, which is then esterified (125). Since direct oxidation avoids the need for HCN and NH, and thus toxic wastes, all new plants have elected to use this technology. Two plants, Oxirane and Rohm and Haas (126), came on-stream in the early 1980s. The Oxirane plant uses the coproduct tert-huty alcohol direcdy rather than dehydrating it first to isobutylene (see Methacrylic acid). 

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