Acrylic acid synthesis routes

Figure 4A.26 Acrylic acid synthesis routes. (Adapted from Ref. S3 a)...

Acryl amide is an important bulk chemical used in coagulators, soil conditioners and stock additives. The chemical synthesis has several drawbacks because the rate of acryl amide formation is lower than the formation of the by-product acrylic acid [54]. Further, the double bonds of the reactants and products cause by-product formations as well as formation of polymerization products. As a result of optimization with methods of molecular engineering, a very high activity of the biocatalyst nitrile hydratase at low temperature is yielded, enabling a successful biotransformation that is superior to the chemical route. Here, the synthesis is carried out at a low temperature of about 5°C, showing a conversion of 100%. 

The preparation of fluorinated alcohols was carried out in multistep routes according to the reported procedures.1012 The synthesis of acrylic and methacrylic esters as shown in Table 11.1 was carried out in a fluorocarbon solvent such as Freon 113 by the reaction of the respective fluorinated alcohol with acryloyl chloride or methacryloyl chloride and an amine acid acceptor such as triethyla-mine with examples shown in Scheme 1. Other attempts to esterify the fluoroalcohols directly with acrylic acid or acrylic anhydride were not successful.11 Product purification by distillation was not feasible because of the temperature required, but purification by percolation of fluorocarbon solutions through neutral alumina resulted in products of good purity identified by TLC, FTIR, and H-, 13C-, and 19F- FTNMRs. 

The dimerization of acrylonitrile is a cheaper route to the synthesis of highly valuable hexamethylenediamine, which is one component of the starting materials for nylon-6,6 [ 16,35] In some cases of the dimerizations of acrylic acid... 

Acetylene-Based Routes. Walter Reppe, die father of modem acetylene chemistry, discovered the reaction of nickel carbonyl with acetylene and water or alcohols to give acrylic acid or esters (75,76). This discovery7 led to several processes which have been in commercial use. The original Reppe reaction requires a stoichiometric ratio of nickel carbonyl to acetylene. The Rohm and Haas modified or semicatalytic process provides 60 —80% of the carbon monoxide from a separate carbon monoxide feed and the remainder from nickel carbonyl (77—78). The reactions for the synthesis of ethyl acrylate are... 

By this route, Monsanto researchers were able to obtain both (S)-naproxen 22 and (S)-ibu-profen 57 by exploiting the Ru/BINAP-catalyzed hydrogenation originally developed by Noyori and his group. In the synthesis of both drugs the required acrylic acid was obtained by the relevant procedure outlined in Fig. 20. 

The current industrial production of methylmethacrylate by the acetone-cyanohydrin process suffers from a number of drawbacks, which make it environmentally unfriendly. In particular, it makes use of a very toxic reactant (HCN) and intermediate (acetone cyanohydrin), and coproduces large amounts of impure ammonium sulphate, contaminated with organic compounds. Among the several alternative synthetic routes which have been proposed, particularly interesting from both the practical and scientific points of view is the single-step oxidation of isobutane to methacrylic acid, intermediate in the synthesis of methylmethacrylate. Several industrial companies have studied this reaction (and the selective oxidation of propane to acrylic acid, as well), and it has been established that the most active and selective catalysts are those which are based on Keggin-type polyoxometalates (POM s), containing phosphorus and molybdenum as the main components [1-18]. 

The synthesis of those 2-bromomethyl-2-aryl-acrylic acids (84) that are not accessible by the above routes due to failure of the MBH reaction can be accomplished by methoxide-induced addition of methyl acrylate to aromatic and heteroaromatic aldehydes (Scheme 3.24). Thus, it may serve as an alternate method in cases where the MBH reaction is slow or fails altogether. 

Monomer Synthesis. Methyl acrylate is commercially produced by routes similar to those used for acrylic acid. 

One of the first asymmetric catalysts to be successfully employed for asymmetric synthesis was the rhodium complex of (12.372a), due to Knowles [12,56], This ligand, which contains two asymmetric P atoms, was used in the Monsanto process for the production of L-amino acids by asymmetric hydrogenation of acylamino-acrylic acids. Only the L isomer, namely L-dopa is effective in the treatment of Parkinson s disease, and the synthesis of this compound by the route (12.374) represents an early commercial success [48]. The synthesis of L-dopa in yields of up to 95% optical purity can also be secured with the rhodium complex of (12.372b), the asymmetry of the catalyst in this case arising from the C atoms. 

Environmentally benign synthesis routes for umbelliferone (I), 7-hydroxy-4-methylcoumarin (II), 3,4-dihydrocoumarin (III), and tricyclic coumarin (IV) (Figure 10.2) were developed using zeolite-H-p or Amberlyst-15 as solid catalysts. This resulted in the minimization of harmful mineral acid wastes. The reactions of resorcinol with acrylic acid, propynoic acid, and ethyl acetoacetate were investigated in toluene and p-chlorotoluene under reflux conditions to obtain coumarins in 60%-80% yield (Hoefnagel et al. 1995 Gunnewegh et al. 1995). 

Although already discovered in 1780 by the Swedish chemist Carl Wilhelm Scheele,who isolated the lactic acid from sour milk, lactic acid has attracted more recently a great deal of attention due to its widespread applications, mainly in food, chemical, cosmetic, and pharmaceutical industries. Also, it has a great potential for the production of biodegradable and biocompatible polylactic acid (PLA) and, besides 3-hydroxypropionic acid, as an intermediate for sugar-based acrylic acid. Lactic acid production can be achieved either by chemical synthesis routes or by fermentative production (lactic acid fermentation). By the chemical synthesis route, a racemic mixture of DL-lactic acid is usually... 

Bhuniya, S. R Rahman, S. Satyanand, A. J. Ghana, M. M. Dave, A. M. Novel route to synthesis of allyl starch and biodegradable hydrogel by copolymerizing allyl-modified starch with meth-acrylic acid and acrylamide. J. Polym. Sci. Part A Poly. Chem. 41(11) 1650-1658 (2003). 

Alternative Synthesis of Acidic Poiymers. There are two approaches to homo- and copolymers of acrylic and methacrylic acids. In addition to the conventional use of acrylic acid and methacrylic acid monomers, the main theme of this article, there exists the possibility of converting polymers of the derivatives of these two monomers to acidic polymers. There would obviously have to be very extenuating circumstances to take this route industrially because of cost penalties. However, there are situations where there is a reason to do this. AvailabiUty of monomers is a good example. Acrylonitrile was at one time more available than acrylic acid in some parts of the world and simple hydrolysis of the polymer gave poly(acrylic acid). Other potential routes exist from such homo- and copolymers of acrylamide, acrylic and methacryUc esters, and acid chlorides. Although not further discussed here, the reader is reminded that polymer synthesis with acrylic monomers is very versatile and forethought is always necessary before plimging ahead. 

One advantage of the RAFT process is its eompatibility with a wide range of monomers, including fnnctional monomers. Thus narrow polydispersity block copolymers have been prepared with monomers containing acid (e.g., acrylic acid), hydroxy (e.g., 2-hydroxyethyl methacrylate), and tertiary amino [e.g., 2-(dimethylamino) ethyl methacrylate] functionality (Chiefari et al., 1998). Linear block copolymers are the simplest polymeric architecmres achievable via RAFT process. There are two main routes for the synthesis of block copolymers by the RAFT process, viz., (i) sequential monomer addition (chain extension) and (ii) synthesis via macro-CTAs (by R- or Z-group approaches). These are schematically shown in Fig. 11.37. Linear block copolymers are the simplest polymeric architectures achievable via RAFT process. 

Actual operating capacities of Reppe carbonylation processes are difficult to estimate since only a few data are available in the literature. However, it is known that some of the syntheses are carried out on an industrial scale, e. g. the synthesis of acrylates from acetylene, carbon monoxide and alcohols (BASF) [1004, 1005], the acetic acid synthesis from methanol and carbon monoxide and the synthesis of higher molecular weight saturated carboxylic acids from olefins, carbon monoxide and water. Propionic acid (30,000 tons/year) and to a smaller extent heptadecanoic dicarboxylic acid are manufactured via the carbonylation route at BASF. Butanol is made from propylene in Japan [1003, 1004]. 

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