Compendio degli studi più significativi con riferimento a proprietà, assunzione, effetti.

Hermens JGH, Jensma A, Feringa BL. Highly Efficient Biobased Synthesis of Acrylic Acid. Angew Chem Int Ed Engl. 2022 Jan 21;61(4):e202112618. doi: 10.1002/anie.202112618. 

Abstract. Petrochemical based polymers, paints and coatings are cornerstones of modern industry but our future sustainable society demands greener processes and renewable feedstock materials. A challenge is to access platform monomers from biomass resources while integrating the principles of green chemistry in their chemical synthesis. We present a synthesis route starting from biomass-derived furfural towards the commonly used monomers maleic anhydride and acrylic acid, implementing environmentally benign photooxygenation, aerobic oxidation and ethenolysis reactions. Maleic anhydride and acrylic acid, transformed into sodium acrylate, were isolated in yields of 85 % (2 steps) and 81 % (4 steps), respectively. With minimal waste and high atom efficiency, this biobased route provides a viable alternative to access key monomers.

Cie, A., Lantz, S., Schlarp, R., & Tzakas, M. (2012). Renewable acrylic acid.

Abstract. Acrylic acid is an important industrial chemical, used as a raw material in a wide variety of consumer end products. The present predominant source of acrylic acid is from the partial oxygenation of propene, produced as a by-product in the industrial production of ethylene and gasoline. Both processes depend heavily on the processing of petrochemicals as the base raw material. The purpose of this process is to produce acrylic acid from renewable carbon sources (such as corn or sugarcane) in an economically preferential manner. Our process has used genetically recombinant Escherichia coli (E. coli) to ferment the carbohydrate content of the proposed feedstock to 3-hydroxypropionic acid (3-HP) which is then dehydrated in the presence of strong acid catalyst (phosphoric acid) to form acrylic acid. The acrylic acid is then purified to the standard required for use as a polymer raw material (99.98% by mass) with total capacity of 160,000 MT/year of product. This design analyzes two proposed locations, the US Midwest or Brazil, and their associated renewable feedstocks, corn or sugarcane juice, respectively. This report investigates the relative economic attractiveness of each option. The US case requires location near an existing industrial ethanol fermentation plant to give easy access to dry-ground corn as a carbohydrate source. This case yields an IRR of 17.56% and an overall NPV of $35.2 million at a 15% discount rate. The Brazil case has comparatively cheaper feedstock, however because of seasonality and total usable carbohydrate content, it requires a greater mass of feedstock and increased capital investment relative to the US case. The NPV difference of the two cases is extremely sensitive to the assumed price of sugarcane juice which has recently shown extraordinary volatility. Based on this analysis, the US location seems most promising; however, detailed laboratory level studies are needed to confirm the profitability and assumptions made.

Straathof AJ, Sie S, Franco TT, van der Wielen LA. Feasibility of acrylic acid production by fermentation. Appl Microbiol Biotechnol. 2005 Jun;67(6):727-34. doi: 10.1007/s00253-005-1942-1. 

Abstract. Acrylic acid might become an important target for fermentative production from sugars on bulk industrial scale, as an alternative to its current production from petrochemicals. Metabolic engineering approaches will be required to develop a host microorganism that may enable such a fermentation process. Hypothetical metabolic pathways for insertion into a host organism are discussed. The pathway should have plausible mass and redox balances, plausible biochemistry, and plausible energetics, while giving the theoretically maximum yield of acrylate on glucose without the use of aeration or added electron acceptors. Candidate metabolic pathways that might lead to the theoretically maximum yield proceed via beta-alanine, methylcitrate, or methylmalonate-CoA. The energetics and enzymology of these pathways, including product excretion, should be studied in more detail to confirm this. Expression of the selected pathway in a host organism will require extensive genetic engineering. A 100,000-tons/year fermentation process for acrylic acid production, including product recovery, was conceptually designed based on the supposition that an efficient host organism for acrylic acid production can indeed be developed. The designed process is economically competitive when compared to the current petrochemical process for acrylic acid. Although the designed process is highly speculative, it provides a clear incentive for development of the required microbial host, especially considering the environmental sustainability of the designed process.

Kausar, A. (2021). Poly (acrylic acid) nanocomposites: Design of advanced materials. Journal of Plastic Film & Sheeting, 37(4), 409-428.

Abstract. Poly(acrylic acid) is a synthetic polymer that is polymerized from acrylic acid monomers. Poly (acrylic acid) is a high molecular weight polymer having good water solubility. Poly(acrylic acid) also exists in the cross-linked forms. Poly(acrylic acid) is an important polymer for making polymeric blends and nanocomposites. This state-of-the-art review is an endeavour to define the unique capabilities of poly (acrylic acid) to form high performance nanocomposites. The nanofiller nanomaterials including carbon nanotube, graphene, nanodiamond, and inorganic nanoparticles are promising nanofillers for a poly(acrylic acid) matrix. Consequently, the article discusses the following categories: poly(acrylic acid)/carbon nanotube, poly(acrylic acid)/graphene, poly(acrylic acid)/nanodiamond, and poly(acrylic acid)/inorganic nanoparticle nanocomposites. The nanocomposite characteristics are significantly enhanced with the added nanoparticles. Especially, the nanoparticles influenced the electrical conductivity, thermal stability, strength, biocompatibility, adsorption, and anti-bacterial features of the poly(acrylic acid) nanocomposites. Their high performance was related to the interface interactions between the matrix and the nanofillers. The poly (acrylic acid) derived nanocomposites have been used to form advanced hybrid materials for batteries, sensors, antibacterial, and water filters.

Park, H., & Robinson, J. R. (1987). Mechanisms of mucoadhesion of poly (acrylic acid) hydrogels. Pharmaceutical research, 4, 457-464.

Abstract. It has been proposed that mucoadhesives which adhere to the gastric mucus layer may be used to prolong gastric retention time of oral dosage forms. Preliminary studies, using acrylic hydrogels, have established that the density of carboxyl groups on the polymer chain is important for mucoadhesion. To understand the role(s) of the carboxyl groups in mucoadhesion, acrylic acid–aerylamide random copolymers [P(AA-co-AM)] were synthesized, and the adhesion strength of the cross-linked polymers to the gastric mucus layer was examined as a function of the pH, initial concentration of the cross-linking agent, degree of swelling, and carboxyl-group density. From the study on mucoadhesion of various P(AA-co-AM), it was found that at least 80% of the vinyl groups of the polymer must possess carboxyl groups in the protonated form. The dependence of mucoadhesion on pH and carboxyl-group density suggests that mucoadhesion occurs through hydrogen bonding. In addition, the density of the cross-linking agent significantly affects mucoadhesion. As the density of the cross-linking agent is lowered, the mucoadhesive strength increases, although the density of carboxyl groups in the test surface area is reduced. It is concluded that for mucoadhesion to occur, polymers must have functional groups that are able to form hydrogen bonds above the critical concentration (80% for vinyl polymers), and the polymer chains should be flexible enough to form as many hydrogen bonds as possible.

Vijay S, Sati OP, Majumdar DK. Acrylic acid-methyl methacrylate copolymer for oral prolonged drug release. J Mater Sci Mater Med. 2010 Sep;21(9):2583-92. doi: 10.1007/s10856-010-4104-7. 

Abstract. Acrylic acid (AA)-methyl methacrylate (MMA) based copolymers, in different molar ratios (3:7, 4:6, 5:5, 6:4, and 7:3) were synthesized using tetrahydrofuran as solvent and AIBN as free radical initiator. Increase in acrylic acid concentration promoted pH-dependent swelling of copolymer and copolymer AA:MMA (3:7) was selected due to minimum swelling. ATR/FTIR and (1)H NMR spectra of the copolymer showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. The copolymer was hemocompatible. Flurbiprofen sodium microspheres made with the copolymer, by oil/oil solvent evaporation, were spherical, anionic (zeta potential -59.0 mV) and contained 4.53% drug. ATR spectrum of microspheres showed peaks for aromatic C=C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. XRD analysis revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26 degrees C against broad endotherms of copolymer and microspheres having peaks at 82.24 and 86.59 degrees C, respectively. The thermogram of microspheres did not show the melting peak of flurbiprofen. The microspheres exhibited no drug release at pH <6.8 and released 83.4 and 99% drug at pH 6.8 and 7.4 in 3 h. The microspheres did not adhere on gastric mucosa at pH 1.2 but showed mucoadhesion time of 28 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in distal ileum, suggesting the potential of the hemocompatible copolymer for enteric coating for prolonged drug release.

Gao, Y., Ou, Y., & Gooßen, L. J. (2019). Pd‐Catalyzed Synthesis of Vinyl Arenes from Aryl Halides and Acrylic Acid. Chemistry–A European Journal, 25(37), 8709-8712.

Abstract. Acrylic acid is presented as an inexpensive, non-volatile vinylating agent in a palladium-catalyzed decarboxylative vinylation of aryl halides. The reaction proceeds through a Heck reaction of acrylic acid, immediately followed by protodecarboxylation of the cinnamic acid intermediate. The use of the carboxylate group as a deciduous directing group ensures high selectivity for monoarylated products. The vinylation process is generally applicable to diversely substituted substrates. Its utility is shown by the synthesis of drug-like molecules and the gram-scale preparation of key intermediates in drug synthesis.