Acrylamide route

The current routes to acrylamide are based on the hydration of inexpensive and readily available acrylonitrile [107-13-1] (C3H3N, 2-propenenittile, vinyl cyanide, VCN, or cyanoethene) (see Acrylonitrile). For many years the principal process for making acrylamide was a reaction of acrylonitrile with H2SO4 H2O followed by separation of the product from its sulfate salt using a base neutralization or an ion exclusion column (68). 

Even ia 1960 a catalytic route was considered the answer to the pollution problem and the by-product sulfate, but nearly ten years elapsed before a process was developed that could be used commercially. Some of the eadier attempts iacluded hydrolysis of acrylonitrile on a sulfonic acid ion-exchange resia (69). Manganese dioxide showed some catalytic activity (70), and copper ions present ia two different valence states were described as catalyticaHy active (71), but copper metal by itself was not active. A variety of catalysts, such as Umshibara or I Jllmann copper and nickel, were used for the hydrolysis of aromatic nitriles, but aUphatic nitriles did not react usiag these catalysts (72). Beginning ia 1971 a series of patents were issued to The Dow Chemical Company (73) describiag the use of copper metal catalysis. Full-scale production was achieved the same year. A solution of acrylonitrile ia water was passed over a fixed bed of copper catalyst at 85°C, which produced a solution of acrylamide ia water with very high conversions and selectivities to acrylamide. 

The yield of acrylonitrile based on propylene is generally lower than the yield of acryhc acid based on the dkect oxidation of propylene. Hence, for the large volume manufacture of acrylates, the acrylonitrile route is not attractive since additional processing steps are involved and the ultimate yield of acrylate based on propylene is much lower. Hydrolysis of acrylonitrile can be controUed to provide acrylamide rather than acryhc acid, but acryhc acid is a by-product in such a process (80). 

Polyamines can also be made by reaction of ethylene dichloride with amines (18). Products of this type are sometimes formed as by-products in the manufacture of amines. A third type of polyamine is polyethyleneimine [9002-98-6] which can be made by several routes the most frequently used method is the polymeriza tion of azitidine [151 -56 ] (18,26). The process can be adjusted to vary the amount of branching (see Imines, cyclic). Polyamines are considerably lower in molecular weight compared to acrylamide polymers, and therefore their solution viscosities are much lower. They are sold commercially as viscous solutions containing 1—20% polymer, and also any by-product salts from the polymerization reaction. The charge on polyamines depends on the pH of the medium. They can be quaternized to make their charge independent of pH (18). 

Most recently new applications for substrate-controlled branched-selective hydroformylation of alkenes substituted with inductively electron-with drawing substituents have emerged. A recent example is the hydroformylation of acrylamide with a standard rhodium/triphenylphosphine catalyst, which yields the branched aldehyde exclusively (Scheme 4) [40]. Reduction of the aldehyde function furnishes 3-hydroxy-2-methylpropionamide, which is an intermediate en route to methyl methacrylate. 

Acrylamide has also been reported to act as a skin tumor initiator in mice by three exposure routes and to increase the yield of lung adenomas in another strain of mice. "... 

Radical carbonylation reaction serves as a powerful tool for the synthesis of a range of carbonyl compounds. Radical carbonylation has been successfully applied to the synthesis of functionalized ketones from alkyl, aryl, and alkenyl halides.The radical aminocarbonylation reaction of alkynes and azaenynes provided efficient routes to 2-substituted acrylamides, lactams, and pyrrolidinones. For example, the aminocarbonylation of 4-pentyn-l-yl acetate 318 initiated by tributyltin hydride (Bu"3SnH) (30mol%) with AIBN (20mol%) gave acrylamide 325 in 92% yield (Scheme 43).A proposed mechanism starts from the addition of tributyltin radical 319 to alkyne... 

E.J. Corey reported (J. Am. Chem. Soc. 2004,126,6230) the first route to 1. The acrylamide 5 was prepared from (S)-threonine methyl ester. Highly diastereoselective (9 1) intramolecular Baylis-Hillman... 

Because reduction of the oligosaccharide occurs in the reductive-amination reaction, affinity adsorbents prepared by this route contain one glycosyl residue fewer than the original oligosaccharide. Adsorbents having such ligands may have low utility. The structure of the product obtained from lactose and 2-aminoethylpoly(acrylamide) by the reductive-amination route is shown in 6. 

Michael addition of amines to bis(acrylamides) has provided a versatile method for the preparation of poly(amidoamines) (70MH1102). A wide variety of piperazine-containing polyamides may be prepared by this route when a piperazine, 1,4-diacryloylpiperazine... 

The current routes to acrylamide are based on the hydration of inexpensive and readily available acrylonitrile (C3H3N, 2-propenenitnle, vinyl cyanide, VCN, 01 cyanoethene) See also Acrylonitrile. 

Methylene-2-azetidmones. A versatile route to these /1-lactams starts with the 2,4,6-triisopropylbenzenesulfonylhydrazone (1) of an oc-keto amide, which can be converted as shown into acrylamides (2).1 Treatment of 2 with -butyllithium (2 equiv.) and then TsCl results in thep-toluenesulfonates 3, which can be isolated. They slowly cyclize to 4 on standing at 25°. The cyclization is more rapid in the presence of NaH.2... 

In basic chemicals, nitrile hydratase and nitrilases have been most successful. Acrylamide from acrylonitrile is now a 30 000 tpy process. In a product tree starting from the addition of HCN to butadiene, nicotinamide (from 3-cyanopyridine, for animal feed), 5-cyanovaleramide (from adiponitrile, for herbicide precursor), and 4-cyanopentanoic acid (from 2-methylglutaronitrile, for l,5-dimethyl-2-piperidone solvent) have been developed. Both the enantioselective addition of HCN to aldehydes with oxynitrilase and the dihydroxylation of substituted benzenes with toluene (or naphthalene) dioxygenase, which are far superior to chemical routes, open up pathways to amino and hydroxy acids, amino alcohols, and diamines in the first case and alkaloids, prostaglandins, and carbohydrate derivatives in the second case. 

One of the best examples for discussing biotransformations in neat solvents is the enzymatic hydrolysis of acrylonitrile, a solvent, to acrylamide, covered in Chapter 7, Section 7.1.1.1. For several applications of acrylamide, such as polymerization to polyacrylamide, very pure monomer is required, essentially free from anions and metals, which is difficult to obtain through conventional routes. In Hideaki Yamada s group (Kyoto University, Kyoto, Japan), an enzymatic process based on a nitrile hydratase was developed which is currently run on a commercial scale at around 30 000-40 000 tpy with resting cells of third-generation biocatalyst from Rhodococcus rhodochrous J1 (Chapter 7, Figure 7.1). 

Figure 5.24 Unlike the chemical route, the biocatalytic hydrolysis of acrylonitrile to acrylamide is highly selective, owing to the specific function of the nitrile hydratase enzyme.

The principal synthetic route to making acrylamide involves the hydration of acrylonitrile (ACRN). In this process an aqueous ACRN solution reacts over... 

Nitto Chemical (now Dia-Nitrix) introduced a biosynthetic route from ACRN to acrylamide in Japan in 1985. This process uses an immobilized nitrile hydratase biocatalyst that converts the ACRN solution to acrylamide with a yield of 99.5%. This high yield allows a concentrated acrylamide solution to be made without the need for ACRN recycle or solution concentration. This process therefore has lower energy costs282. The initial plant capacity was 4,000 tonnes per year it was expanded to 20,000 tonnes per year in 1991 and that is its capacity as of 2002. 

Kolen ko YV, Amakawa K, Naumann d Alnoncourt R, Girgsdies F, Weinberg G, Schlogl R, Trunschke A. Unusual phase evolution in MoVTeNb oxide catalysts prepared by a novel acrylamide-gelation route. ChemCatChem. 2012 4(4) 495-503. 

---