Monomer Of Nylon Research Articles

An Integrated Cofactor/Co‐Product Recycling Cascade for the Biosynthesis of Nylon Monomers from Cycloalkylamines

AbstractWe report a highly atom‐efficient integrated cofactor/co‐product recycling cascade employing cycloalkylamines as multifaceted starting materials for the synthesis of nylon building blocks. Reactions using E. coli whole cells as well as purified enzymes produced excellent conversions ranging from >80 and 95 % into desired ω‐amino acids, respectively with varying substrate concentrations. The applicability of this tandem biocatalytic cascade was demonstrated to produce the corresponding lactams by employing engineered biocatalysts. For instance, ϵ‐caprolactam, a valuable polymer building block was synthesized with 75 % conversion from 10 mM cyclohexylamine by employing whole‐cell biocatalysts. This cascade could be an alternative for bio‐based production of ω‐amino acids and corresponding lactam compounds.

Multilayer Engineering of Enzyme Cascade Catalysis for One-Pot Preparation of Nylon Monomers from Renewable Fatty Acids

Enzyme cascade catalysis has critical problems in obtaining the high concentrations of products, such as the low stabilities and activities of biocatalysts and the inhibition by hydrophobic reactan...

Producing adipic acid without the nitrous oxide.

Synthesis of nylon monomer from butadiene avoids emission of a potent greenhouse gas

Process Intensification Approaches to Organic Electrosynthesis: Towards Sustainable Nylon Production

The effect of fossil-fuel-derived carbon dioxide (CO2) emissions on the environment has fueled the interest in electrifying the chemical industry through electrochemistry. The implementation of electrochemical processes for the production of large volume chemicals can allow for the direct integration of renewable energy sources into chemical manufacturing. Additionally, these processes provide an opportunity for significant energy efficiency improvements and the introduction of previously unexplored chemical transformations. Although inorganic electrosynthetic processes have been successfully implemented in industry at scale (e.g. chloro-alkali and Aluminum production), the use of electrochemical methods for the production of organic chemicals has been limited, even if their potential impact is significantly larger. In spite of their advantages, organic electrosynthetic processes face common challenges such as limited reactant concentrations in the electrolyte, a complex set of competing organic side reactions, and the narrow electrochemical stability window of aqueous electrolytes.1 The low solubility of organic reactants, together with the use of high current densities that maximize reaction throughput, often result in mass transport limitations that can lower reaction selectivity. As a model case study, this work focuses on the electrohydrodimerization of acrylonitrile (AN) to adiponitrile (ADN), a precursor to Nylon 6,6.2 Although this is considered the largest and most successful organic electrosynthesis implemented in industry, it faces many challenges owing to its limited energy conversion and selectivity. Through a combination of experimental insights and artificial-intelligence-enabled models, we elucidate process intensification guidelines for mass transport enhancement in organic electrosynthesis via electrolyte optimization, complex voltage dosing, and membrane-based electrochemical flow reactors. Moreover, this work explores the development of the sequential electro-hydrogenation of ADN to hexamethylenediamine (HMDA), paving the way for a continuous electrochemical process for the production of Nylon monomers. Our results provide insights on the main challenges faced in organic electrosynthesis, and demonstrate how innovative process intensification approaches can address these challenges and enhance the competitiveness of electrochemical routes for the production of valuable organic chemicals. Blanco, D. E.; Modestino, M. A., Organic Electrosynthesis for Sustainable Chemical Manufacturing. Trends in Chemistry 2019, 1 (1), 8-10.Blanco, D. E.; Dookhith, A. Z.; Modestino, M. A., Enhancing selectivity and efficiency in the electrochemical synthesis of adiponitrile. Reaction Chemistry & Engineering 2019, 4 (1), 8-16.

Catalytic transformation of 2,5-furandicarboxylic acid to adipic acid over niobic acid-supported Pt nanoparticles.

The conversion of biomass-derived molecules into adipic acid represents a highly attractive green route for sustainable production of adipic acid, a key monomer of nylon 66 and polyurethane. Here, we report the direct synthesis of adipic acid from 2,5-furandicarboxylic acid, which can be obtained from cellulose-based 5-hydroxymethylfurfural, using a niobic acid-supported platinum catalyst under hydrogen in water.

Biosynthesis of the Nylon 12 Monomer, ω-Aminododecanoic Acid with Novel CYP153A, AlkJ, and ω-TA Enzymes.

Bioplastics are derived from renewable biomass sources, such as vegetable oils, cellulose, and starches. An important and high-performance member of the bioplastic family is Nylon 12. The biosynthesis of ω-amino dodecanoic acid (ω-AmDDA), the monomer of Nylon 12 from vegetable oil derivatives is considered as an alternative to petroleum-based monomer synthesis. In this study, for the production of ω-AmDDA from dodecanoic acid (DDA), the cascade of novel P450 (CYP153A), alcohol dehydrogenase (AlkJ), and ω-transaminase (ω-TA) is developed. The regioselective ω-hydroxylation of 1 mM DDA with near complete conversion (>99%) is achieved using a whole-cell biocatalyst co-expressing CYP153A, ferredoxin reductase and ferredoxin. When the consecutive biotransformation of ω-hydroxy dodecanoic acid (ω-OHDDA) is carried out using a whole-cell biocatalyst co-expressing AlkJ and ω-TA, 1.8 mM ω-OHDDA is converted into ω-AmDDA with 87% conversion in 3 h. Finally, when a one-pot reaction is carried out with 2 mM DDA using both whole-cell systems, 0.6 mM ω-AmDDA is produced after a 5 h reaction. The results demonstrated the scope of the potential cascade reaction of novel CYP153A, AlkJ, and ω-TA for the production of industrially important bioplastic monomers, amino fatty acids, from FFAs.

Phase Morphology and Dynamic Mechanical Properties of Nylon 6 Based Blends Prepared via Successive In Situ Ring Opening Polymerization

ABSTRACTAcrylonitrile butadiene styrene (ABS)/nylon 6 blends were prepared via in-situ polymerization and a compatibilization method with various blend compositions. The monomer of nylon 6 (ϵ-caprolactam) was polymerized using activated anionic ring opening polymerization in the presence of ABS. Hexamethylene diisocyanate (HDI) and styrene maleic anhydride (SMA) were used as microactivator and macroactivator at different concentrations. Phase morphology and dynamic mechanical properties were evaluated; and the blending method was compared with ordinary reactive extruding (melt blending). In samples with dispersed structure, the dispersed particle size decreased with increasing SMA. Also, the effects of SMA at lower levels of HDI were more significant, probably due to competition between the activators in the reaction. In some of the in-situ prepared blends, even in the co-continuous structure, particles with sizes under 500 nm were observed. A noteworthy observation in micrographs was that the sizes of the dispersed particle prepared by the in situ method were less than those prepared by the compounding method. Even the uncompatibilized in situ samples had a finer particle size in comparison with the ordinary compatibilized samples. The phase inversion point was also investigated; it was affected by both micro and macro activator concentrations. At higher HDI or SMA content, a lower phase inversion concentration (φNylon6) was observed. In samples with an ABS dispersed phase, after in situ compatibilization using SMA, extraction of the ABS phase did not happen easily in the given time because of the surrounding copolymer at the particles surfaces. These blends had ultra-small particles (under 200 nm). Comparison of changes in the TgABS and TgNylon6 showed another interesting result. While the Tgs of samples prepared by the compounding method shifted about 3°C, the Tgs of samples prepared by the in situ method shifted more obviously (around 4–30°C). This indicated the powerful compatibilization caused by the in situ polymerization and compatibilization method. All results confirmed that the in situ polymerization and compatibilization method should be considered to be useful for production of ABS/nylon 6 blends.

Chemoenzymatic synthesis of a peptide containing nylon monomer units for thermally processable peptide material application

Chemoenzymatic polymerization by papain produced the copolymer of l-leucine and nylon monomers, which showed melting behavior at around 200 °C.

In-situ Polymerization of Nylon-Cellulose Nano composite

Polymeric Nano composite has been strongly studied due to the improvement achieved when a little amount of Nano sized particles are added to the polymer matrix. This is primarily due to large surface area which increased the interaction between the nanoparticles and the polymer. There are different routes for preparation of the polymer Nano composite with Nano fillers it can be melt compound, in-situ polymerization and the solvent method. The in-situ method was found to be best method due to that the nanoparticle is introduced directly to the monomer and it allowed for few minutes to disperse well to the monomer before the initiator is added to start polymerization. The in-situ method gives control over the particle size and morphology. The present studies investigate the surface morphology and thermal properties of nylon when the cellulose Nano-whiskers of different content was added into nylon monomer. SEM for surface studies, TGA for thermal stabilities and FTIR for chemical properties were studied. TGA results reveal that nylon thermal properties changes with addition of Nano crystals compared to pure nylon.

Overexpression of transport proteins improves the production of 5-aminovalerate from l-lysine in Escherichia coli.

Bacterial transporters mediate the exchanges between intracellular and extracellular environments. Modification of transport route could be applied to speed up the metabolic reactions and promote the production of aimed compounds. Herein, lysine 2-monooxygenase (DavB) and δ-aminovaleramidase (DavA) were co-expressed in Escherichia coli BL21(DE3) to produce nylon-5 monomer 5-aminovalerate from l-lysine. Then, PP2911 (4-aminobutyrate transporter in Pseudomonas putida) and LysP (the lysine specific permease in E. coli) were overexpressed to promote 5-aminovalerate production using whole cells of recombinant E. coli. The constructed E. coli strain overexpressing transport proteins exhibited good 5-aminovalerate production performance and might serve as a promising biocatalyst for 5-aminovalerate production from l-lysine. This strategy not only shows an efficient process for the production of nylon monomers but also might be used in production of other chemicals.

Papain-Catalyzed Synthesis of Polyglutamate Containing a Nylon Monomer Unit.

Peptides have the potential to serve as an alternative for petroleum-based polymers to support a sustainable society. However, they lack thermoplasticity, owing to their strong intermolecular interactions. In contrast, nylon is famous for its thermoplasticity and chemical resistance. Here, we synthesized peptides containing a nylon unit to modify their thermal properties by using papain-catalyzed chemoenzymatic polymerization. We used l-glutamic acid alkyl ester as the amino acid monomer and nylon 1, 3, 4, and 6 alkyl esters as the nylon unit. Papain catalyzed the copolymerization of glutamic acid with nylon 3, 4, and 6 alkyl esters, whereas the nylon 1 unit could not be copolymerized. Other proteases used in this study, namely, bromelain, proteinase K, and Candida antarctica lipase (CALB), were not able to copolymerize with any nylon units. The broad substrate specificity of papain enabled the copolymerization of l-glutamic acid with a nylon unit. The peptides with nylon units demonstrated different thermal profiles from that of oligo(l-glutamic acid). Therefore, the resultant peptides with various nylon units are expected to form fewer intermolecular hydrogen bonds, thus altering their thermal properties. This finding is expected to broaden the applications of peptide materials and chemoenzymatic polymerization.

Bio–based Pentenoic Acids as Intermediates to Higher Value‐Added Mono‐ and Dicarboxylic Acids

AbstractThe acid catalyzed reactive distillation of γ‐valerolactone yields pentenoic acids (PEAs) which can be obtained in >90 % purity and >97 % selectivity. The PEAs (five isomers) can be converted into a number of useful products with commercial relevance. The hydroxycarbonylation of PEAs yields adipic acid (a Nylon monomer) in very high selectivity and with good activity. Self‐metathesis of PEAs yields C6 – C8 unsaturated dicarboxylic acids which after hydrogenation produces a mixture of adipic acid, pimelic acid and suberic acid. If the PEAs are first subjected to ethenolysis; acrylic acid, 3‐butenoic acid, and 4‐pentenoic acid are produced. The self‐metathesis of 3‐butenoic acid produces β‐hydromuconic acid in >99 % selectivity which can be hydrogenated to adipic acid, whereas the self‐metathesis of 4‐PEA followed by hydrogenation gives suberic acid with 99 % selectivity. 3‐Butenoic acid can also be hydroxycarbonylated to produce glutaric acid in 99 % selectivity.

Efficient and sustainable transformation of gamma-valerolactone into nylon monomers

A route for efficient synthesis of bio-nylon monomers from gamma-valerolactone has been developed.

Thermostabilization of glutamate decarboxylase B from Escherichia coli by structure-guided design of its pH-responsive N-terminal interdomain

Glutamate decarboxylase B (GadB) from Escherichia coli is a highly active biocatalyst that can convert l-glutamate to γ-aminobutyrate (GABA), a precursor of 2-pyrrolidone (a monomer of Nylon 4). In contrast to vigorous studies of pH shifting of GadB, mesophilic GadB has not been stabilized by protein engineering. In this study, we improved the thermostability of GadB through structural optimization of its N-terminal interdomain. According to structural analysis, the N-terminal fourteen residues (1–14) of homo-hexameric GadB formed a triple-helix bundle interdomain at acidic pH and contributed to the thermostability of GadB in preliminary tests as the pH shifted from 7.6 to 4.6. GadB thermostabilization was achieved by optimization of hydrophobic and electrostatic interactions at the N-terminal interdomain. A triple mutant (GadB-TM: Gln5Asp/Val6Ile/Thr7Glu) showed higher thermostability than the wild-type (GadB-WT), i.e., 7.9 and 7.7°C increases in the melting temperature (Tm) and the temperature at which 50% of the initial activity remained after 10min incubation (T5010), respectively. The triple mutant showed no reduction of catalytic activity in enzyme kinetics. Molecular dynamics (MD) simulation at high temperature showed that reinforced interactions of the triple mutant rigidified the N-terminal interdomain compared to the wild-type, leading to GadB thermostabilization.

Droplet characterisation of molten caprolactam for additive manufacturing applications

Droplet formation characteristics of molten caprolactam, the monomer of nylon 6, are reported in this article as part of research to develop a novel inkjet additive manufacturing process. Initial investigations confirmed the jettability of molten caprolactam at 80 °C with a printhead and recommended a range of parameters for a stable jet array. High-speed imaging was used to study the interactions between the melt and the printhead. Droplets were generated at voltages higher than 12.5 V. Nozzle wetting and crosstalk in adjacent nozzles were observed especially at higher voltages. Jetting frequency did not affect the droplet characteristics. By varying the jetting voltage though significant changes to the droplet shape, evolution and kinetics were observed. Satellite droplets were formed by disintegration of the tail at lengths of about 1 mm when a jetting voltage of 25.0 V was used. An increase of voltage from 15.0 V to 25.0 V increased the droplet velocity from 2 m/s to 8 m/s. Reynolds and Weber numbers predicted there would not be splashing upon droplet impact, which was confirmed by experiments when impinging molten caprolactam droplets on cold and heated substrates. The droplet formation study suggested a set of jetting parameters to be used for the next stage of the research on the inkjet process development.

Effects of glutamate decarboxylase and gamma-aminobutyric acid (GABA) transporter on the bioconversion of GABA in engineered Escherichia coli

Gamma-aminobutyric acid (GABA) is a non-essential amino acid and a precursor of pyrrolidone, a monomer of nylon 4. GABA can be biosynthesized through the decarboxylation of L: -glutamate by glutamate decarboxylase. In this study, the effects of glutamate decarboxylase (gadA, gadB), glutamate/GABA antiporter (gadC) and GABA aminotransferase (gabT) on GABA production were investigated in Escherichia coli. Glutamate decarboxylase was overexpressed alone or with the glutamate/GABA antiporter to enhance GABA synthesis. GABA aminotransferase, which redirects GABA into the TCA cycle, was knock-out mutated. When gadB and gadC were co-overexpressed in the gabT mutant strain, a final GABA concentration of 5.46 g/l was obtained from 10 g/l of monosodium glutamate (MSG), which corresponded to a GABA yield of 89.5%.

Jetting stability of molten caprolactam in an additive inkjet manufacturing process

This paper proposes a novel additive manufacturing concept which uses inkjet technology to manufacture parts in nylon 6. The methodology involved a series of experiments to investigate whether caprolactam, the monomer of nylon 6, could be jetted in the molten state. Once this was established, further experiments were undertaken to determine the possible boundaries for the process parameters. The main parameters were the vacuum level at which the melt could be controlled for stable jetting, the jetting voltage amplitude and frequency which were investigated against the jet array stability by monitoring the printhead’s nozzle plate. The jet(s) instability behaviour were characterised in different sets of experiments in order to optimise the jetting conditions for the molten caprolactam. The jetting voltage and vacuum level were found to have a significant effect whereas the jetting frequency did not. Instabilities occurred in the form of individual deviating jet trajectory and also jet array failures. These were found to be initiated by air motion when using inappropriate jetting voltage resulting in incorrect jet trajectory. A combination of incorrect jetting voltage and vacuum level led to air bubble entrapment during jetting and, therefore, rapid failure of the jets. Analysis of jet array instability led to a stable process window for further stages of the research on the additive inkjet manufacturing process development.

Migration of ɛ-caprolactam residues in packaging intended for contact with fatty foods

Residues of ɛ-caprolactam (CAP), a precursor monomer of nylon 6 used in food packaging materials, can migrate into foodstuffs. This work evaluated the migration of CAP into 95% ethanol (a fatty food simulant). A total of 8 (35%), 1 (33%), 2 (100%) and 3 (100%) packages intended for contact with bologna sausage, turkey blanquette, poultry breast, and pâté, respectively, presented specific migration levels exceed the limit established in Brazil and Europe (15 mg/kg of food). Therefore, in the interest of protecting human health, it is recommended that Brazilian government and its agencies develop measures to control and monitor food packaging materials containing nylon 6.

Validação de método analítico para determinar a migração de ε-caprolactama das embalagens para alimentos gordurosos

e-Caprolactam (CAP) is a monomer of nylon 6 used as food packaging for bologna sausage, turkey blanquettes, fowl breast, pâtes and ham luncheon meat. After polymerization a part of the monomer can remain in the packaging and migrate into the food. The aim of this work was develop and validate a single laboratory method to determine CAP in ethanol 95% that simulates fatty food characteristics. Thus, linear range was 2 to 32 mg/L of CAP, detection and quantification limits were 0.83 and 1.63 mg/L, respectively. Repeatability showed Hor Rat values lower than 2 while recovery range was 97.5 to 106.5%. The method was considered adequate for purpose.

Estudos sobre a toxicologia da ε-caprolactama

A ε-caprolactama (CAP) é um monômero precursor de polímeros denominados nylon 6. Esses polímeros destinam-se à produção de tapetes, vestuário e materiais plásticos tais como equipamentos, sistemas e componentes automotivos, conectores, além de embalagens plásticas. Resíduos de CAP podem migrar de embalagens plásticas de nylon 6 para os alimentos. Diante disso, foi de interesse realizar uma revisão dos efeitos relativos à exposição à CAP e o seu impacto sobre a saúde humana. Estudos epidemiológicos indicam a possibilidade da CAP causar inflamações oculares e cutâneas, além de irritações no sistema respiratório. Pode ocorrer ainda hipotensão, taquicardia, palpitações, rinorréia, ressecamento nasal, efeitos geniturinários e sobre a reprodução como distúrbios nas funções menstrual e ovariana, e complicações no parto; além de problemas neurológicos e hematológicos. Estudos com animais são consistentes com tais relatos. Os estudos de genotoxicidade in vitro e in vivo por via oral e intraperitoneal mostram em sua grande maioria, resultados negativos, bem como ausência de efeitos carcinogênicos em ratos e camundongos e sobre o desenvolvimento e reprodução em ratos e coelhos.