Mohammad Asif Ali

1H NMR and FT-IR dataset based structural investigation of poly(amic acid)s and polyimides from 4,4′-diaminostilbene

Structural investigation of polymers by various available analytical methods is important in order to correlate the structure with polymer properties for which understanding of polymer structure is very important factor. The data presented here in this article shows the 1H NMR spectra used for the characterization of prepared poly(amic acid)s (PAAs). It is often difficult to assigns the peak in NMR of polymers due to its complexity. Data presented here helps in assigning the proton peak in complex NMR of PAAs prepared from aromatic diamines. Further functionality in polymer chains can be confirmed by FT-IR spectra. Change in functionality during some reaction or process can be monitored by disappearance or appearance of peaks in FT-IR. The complete imidization of PAAs to Polyimides (PIs) is difficult to analyze because of the chemical stability i.e. insolubility of PIs in most of the solvent therefore the completion of imidization process was confirmed using FTIR.

Microbe-Derived Itaconic Acid: Novel Route to Biopolyamides

Itaconic acid is a white crystalline organic compound with the formula C5O4H4 and is classified as an unsaturated carbonic acid. Today, this organic acid is widely used for the production of resins, biofuel components, pharmaceutical products, artificial glass, plastics and in the textile industry and agriculture. Because many potentially useful substances can be prepared from this organic acid it can be considered a platform chemical. Using biotechnology, itaconic acid can be synthesized from Aspergillus sp. such as A. itaconicus and A. terreus, which have ability to produce the unsaturated itaconic acid. Itaconic acid has been particularly used in the vinyl polymer industries but recently we have used it for the development of novel biobased polyamides. Polyamides are industrially established compounds containing a –CONH– linkage, which can enhance the performance of materials, especially thermal and mechanical moduli. Itaconic acid-based polyamides contain a pyrrolidone ring, which constitutes the polyamide backbone. This pyrrolidone ring backbone is promising for the future development of biobased materials for a wide range of engineering plastics.

Biological Routes for the Synthesis of Platform Chemicals from Biomass Feedstocks

Development of processes to produce fuels and chemical from biomass offers an exciting opportunity to achieve a sustainable supply from renewable sources as compared to fossil fuel-based methods. Technologies relying only on chemical catalytic routes have shown limitations in achieving the desired yield of a product molecule. Therefore, recent developments in research have emphasized the importance of integrating a biocatalytic route to a chemo-catalytic route to produce commodity chemicals with high conversion and selectivity. Microorganisms including bacteria, fungus and algae are versatile in nature and have potential to yield platform molecules which can be upgraded to produce their petrochemical counterparts. Genetic engineering techniques combined with metabolic flux analysis are employed to further enhance the productivity. On subsequent purification, the platform molecule may be used as a reactant for chemo-catalytic processing to produce a range of high-value chemicals. In this way, a novel integrated fermentation and catalytic processing strategy is envisaged, which will open avenues for producing chemicals from renewable sources. The chapter covers the progress made in this direction by summarizing the routes for producing a platform molecule via biocatalytic transformations.

Bio-based mesoporous sponges of chitosan conjugated with amino acid-diketopiperazine through oil-in-water emulsions

Fully bio-based chitosan derivative was synthesized using 3-benzyl-2,5-diketopiperazine-6-acetic acid (DKP) activated by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. From IR and 1H NMR spectra, the structure of the bioconjugated chitosan and the quantitative modification were confirmed. Oil-in-water (o/w) emulsion of the obtained product was presented with the various ratios of water and benzene solution. Continuously the obtained o/w emulsions were freeze-dried to produce the mesoporous sponge, depended on the ratio of the water and benzene. These amphiphilic properties were observed by the property of the pendant DKP moieties in chitosan. The pore size in the sponges was controlled in a range from 0.1 to 0.3 μm by changing the solvent ratios.

Polypeptide gels incorporating the exotic functional aromatic amino acid 4-amino-L-phenylalanine

High-molecular-weight polypeptides with functional aromatic side chains, poly(4-amino-L-phenylalanine), 4APhe, were prepared by the metal-initiated polymerization of the Nα-carboxyanhydride of the corresponding amino acid, which is a microbial derivative of phenylalanine. The polypeptide P4APhe has good water solubility as opposed to those of the conventional aromatic poly(amino acid)s such as poly(L-phenylalanine) or poly(L-tyrosine). On the other hand, P4APhe shows an in situ gelation ability upon the swelling of dried samples in solvents, due to the formation of crystalline β-sheet domains that work as cross-linking junctions. Moreover, the cationic copolymers of 4APhe with L-lysine showed a pH-responsive gelling behavior resulting from changes in the amphipathic balance of crystalline β-strands, α-helical structures, and hydrophilic random coils. Notably, small amounts of 4APhe units in copolypeptides with L-lysine were found to enhance adoption α-helical conformations.