Production Of Nylon Research Articles

OPTIMASI SINTESIS ASAM AZELAT DARI ASAM OLEAT DAN HIDROGEN PEROKSIDA MENGGUNAKAN KATALIS ASAM TUNGSTAT


 Azealic acid is an oleochemical product which is an output from oleic acid with oxidation cleavage process and commonly its aplication in polymer industry such as nylon production, plastic industry, glue industry and also as fiber in polyester industry. The purpose of this research is to obtain comparison design and analysis of variance in two method of synthesis azelaic acid namely one step and two steps oxidation. The result design reviewed by Response Surface Methodology using Minitab 17 trial version program with percent mass of the catalyst variable, molar ratio of the substrate variable and temperature variable. Based on the statistic analysis the percentage conversion (Y)in one step Y : 97,99 + 3,907X1 + 3,651X2 – 4,556X3 – 1,467X12 – 4,299X22 – 4,453X32 + 0,57X1X2 + 0,63X1X3 + 1,37X2X3 and for two steps Y : 98,505 + 6,164X2 + 2,164X3-7,83X22-5,18X32. The design has R2 = 92,80 % for one step and 89,95 % in two steps.

Improved cadaverine production from mutant Klebsiella oxytoca lysine decarboxylase

Cadaverine has the potential to become an important platform chemical for the production of nylon. Previously, a system that overexpresses the Klebsiella oxytoca lysine decarboxylase in Escherichia coli was engineered. The system was optimized by codon optimization, and tuning the expression level of the gene by testing various promoters and inducer concentrations. Here, we further improved the system by optimizing the sequence located in the region of the ribosome‐binding site in order to enhance translation efficiency. We also identified mutant lysine decarboxylase enzymes that demonstrated enhanced cadaverine‐production ability. Together, these modifications increased cadaverine production in the system by 50%, and the system has a yield of 80% from lysine‐HCl under the conditions we tested. This is the first time that a system to produce cadaverine using the lysine decarboxylase from K. oxytoca performed at a level that is competitive with the traditional systems using the E. coli lysine decarboxylases in both lab‐scale and batch fermentation conditions.

Synthesis and characterization of MC nylon/modified yttrium hydroxide nanocomposites

ABSTRACTIn this article, monomer casting (MC) nylon is synthesized. MC nylon could replace nonferrous metals in certain applications, including gears, wheels, and other moving parts. However, compared with metals, MC nylon products have poor strength and stiffness, and crack easily, especially at low temperatures. In addition, the dimensional stability of MC nylon is poor, especially in the large casting nylon products, causing significant internal stresses due to shrinkage. Thus, MC nylon cracks easily when cast and molded. The yttrium hydroxide particles are modified by stearic acid and dispersed in the caprolactam. The polymerization time is short due to fast anionic polymerization. Copolymerization with different ratios of yttrium hydroxide particles can be used to prepare the copolymer. The effects of different amounts of yttrium hydroxide on the performance of the monomer casting nylon are studied. The products are characterized using X‐ray diffraction, impact, and tensile testing. When the percentage of modified yttrium hydroxide is 0.3 wt %, the composite exhibits the maximum impact strength, thus the 0.3 wt % of modified yttrium hydroxide is the suitable percentage to enhance the impact strength of MC nylon. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43356.

Interlaboratory Study on Caprolactam Test for Food-Contact Nylon Products.

The Japanese Food Sanitation Law sets a limit on the migration level of caprolactam for food-contacting nylon products. Here, we carried out an interlaboratory study in twenty laboratories to evaluate the performance of the official GC-FID test method and a GC-MS method as an alternative test method to the official method. Each laboratory quantified caprolactam in three test solutions in 20% ethanol as blind duplicates using GC-FID or GC-MS. The official method (GC-FID with absolute calibration) gave trueness, repeatability (RSDr) and reproducibility (RSDr) values of 96-97%, 3.3-5.4% and 4.0-6.7%, respectively. These values met the target criteria (trueness: 80-110%, RSDr: 10%, RSDr: 25%). The performance of the method was further improved by the introduction of heptalactam as an internal standard. As for GC-MS method, some values of the RSDr exceeded 10% when absolute calibration was used. However, when an internal standard was introduced, the trueness, RSDr and RSDr of GC-MS method were all acceptable at 94-96%, 2.0-4.4% and 7.0-9.4%, respectively. Therefore, GC-MS with an internal standard is available as an alternative test method to the official method.

Isothermal and nonisothermal crystallization kinetics of bio-sourced nylon 69

Bio-sourced nylon 69, one of promising engineering plastics, has a great potential in developing sustainable technology and various commercial applications. Isothermal and nonisothermal crystallization kinetics of nylon 69 is a base to optimize the process conditions and establish the structure–property correlations for nylon 69, and it is also highly beneficial for successful applications of nylon products in industry. Isothermal and nonisothermal crystallization kinetics has been investigated by differential scanning calorimetry for nylon 69, bio-sourced even–odd nylon. The isothermal crystallization kinetics has been analyzed by the Avrami equation, the calculated Avrami exponent at various crystallization temperatures falls into the range of 2.28 and 2.86. In addition, the Avrami equation modified by Jeziorny and the equation suggested by Mo have been adopted to study the nonisothermal crystallization. The activation energies for isothermal and nonisothermal crystallization have also been determined. The study demonstrates that the crystallization model of nylon 69 might be a two-dimensional (circular) growth at both isothermal and nonisothermal crystallization conditions. Furthermore, the value of the crystallization rate parameter (K) decreases significantly but the crystallization half-time (t1/2) increases with the increase of the isothermal crystallization temperature. To nonisothermal crystallization, the crystallization rate increases as the cooling rate increases according to the analysis of Jeziorny's theory. The results of Mo's theory suggest that a faster cooling rate is required to reach a higher relative degree of crystallinity in a unit of time, and crystallization rate decreases when the relative degree of crystallinity increases at nonisothermal crystallization conditions.

Development of a chronic inhalation reference value for hexamethylenediamine using an exposure model based on the dihydrochloride salt

The Texas Commission on Environmental Quality has developed a chronic inhalation Reference Value (ReV) for hexamethylenediamine (HMDA, CAS 124-09-4) based on respiratory effects identified in an animal study. HMDA is used in the fiber and plastics industry as an intermediate in the production of nylon, high-strength resins and polyamide adhesives. As a toxicant, HMDA acts primarily as a respiratory irritant with effects occurring in the upper respiratory tract, although systemic effects have been noted at higher concentrations. ReVs are chemical-specific air concentrations derived to protect human health. Acute and chronic ReVs were developed for HDMA based on an inhalation study conducted by the National Toxicology Program (NTP), which used the salt of HMDA, hexamethylenediamine dihydrochloride (HDDC, CAS 6055-52-3). For the chronic evaluation, rats and mice were exposed to 0, 1.6, 5, 16, 50 and 160 mg HDDC/m3 for 13 weeks. The critical effect identified for the most sensitive species was hyaline degeneration in the olfactory epithelium in mice. The data provided in this study were suitable to benchmark concentration (BMC) modeling. Dosimetric adjustments using the rat and mouse Multiple-Path Particle Dosimetry Model (version 3.0) were made to the 95% lower limit of the BMC(10) to determine the human equivalent point of departure. Uncertainty factors were applied to account for variation in sensitivity within the human population, toxicodynamic differences between mice and humans, and use of a subchronic study. The ReV was initially calculated for HDDC and then adjusted for HMDA. The chronic ReV is 1.8 µg/m3 for respirable HMDA ≤ 10 µm in diameter.

Continuously Conducted Selective Hydrogenation of Benzene to Cyclohexene in a Four‐Phase System

AbstractCurrently, the production of nylon 6 and nylon 6.6 is based on the complete hydrogenation of benzene to cyclohexane over nickel or platinum catalysts and its subsequent oxidation at very low conversions to a mixture of cyclohexanol/cyclohexanone. This mixture is further reacted to ϵ‐caprolactam or adipic acid. Alternatively, the reaction can be carried out by selective hydrogenation of benzene to cyclohexene and subsequent hydration with acidic catalysts to cyclohexanol. A laboratory method for the selective hydrogenation of benzene in a continuous stirred‐tank reactor (CSTR) using a gas/liquid/liquid/solid system is presented.

Identification of novel transaminases from a 12‐aminododecanoic acid‐metabolizing Pseudomonas strain

A Pseudomonas species [Pseudomonas sp. strain amino alkanoate catabolism (AAC)] was identified that has the capacity to use 12-aminododecanoic acid, the constituent building block of homo-nylon-12, as a sole nitrogen source. Growth of Pseudomonas sp. strain AAC could also be supported using a range of additional ω-amino alkanoates. This metabolic function was shown to be most probably dependent upon one or more transaminases (TAs). Fourteen genes encoding putative TAs were identified from the genome of Pseudomonas sp. AAC. Each of the 14 genes was cloned, 11 of which were successfully expressed in Escherichia coli and tested for activity against 12-aminododecanoic acid. In addition, physiological functions were proposed for 9 of the 14 TAs. Of the 14 proteins, activity was demonstrated in 9, and of note, 3 TAs were shown to be able to catalyse the transfer of the ω-amine from 12-aminododecanoic acid to pyruvate. Based on this study, three enzymes have been identified that are promising biocatalysts for the production of nylon and related polymers.

Reducing Isozyme Competition Increases Target Fatty Acid Accumulation in Seed Triacylglycerols of Transgenic Arabidopsis

One goal of green chemistry is the production of industrially useful fatty acids (FAs) in crop plants. We focus on hydroxy fatty acids (HFAs) and conjugated polyenoic FAs (α-eleostearic acids [ESAs]) using Arabidopsis (Arabidopsis thaliana) as a model. These FAs are found naturally in seed oils of castor (Ricinus communis) and tung tree (Vernicia fordii), respectively, and used for the production of lubricants, nylon, and paints. Transgenic oils typically contain less target FA than that produced in the source species. We hypothesized that competition between endogenous and transgenic isozymes for substrates limits accumulation of unique FAs in Arabidopsis seeds. This hypothesis was tested by introducing a mutation in Arabidopsis diacylglycerol acyltransferase1 (AtDGAT1) in a line expressing castor FA hydroxylase and acyl-Coenzyme A:RcDGAT2 in its seeds. This led to a 17% increase in the proportion of HFA in seed oil. Expression of castor phospholipid:diacylglycerol acyltransferase 1A in this line increased the proportion of HFA by an additional 12%. To determine if our observations are more widely applicable, we investigated if isozyme competition influenced production of ESA. Expression of tung tree FA conjugase/desaturase in Arabidopsis produced approximately 7.5% ESA in seed lipids. Coexpression of VfDGAT2 increased ESA levels to approximately 11%. Overexpression of VfDGAT2 combined with suppression of AtDGAT1 increased ESA accumulation to 14% to 15%. Our results indicate that isozyme competition is a limiting factor in the engineering of unusual FAs in heterologous plant systems and that reduction of competition through mutation and RNA suppression may be a useful component of seed metabolic engineering strategies.

EYE ON CHINA

WuXi PharmaTech acquires NextCODE Health to create global leader in genomic medicine. CardioKinetix completes enrollment in Chinese trial of first-of-its-kind parachute device for treatment of heart failure. Hua Medicine raises $25 million in Series B financing to start Phase 2 trials. BCI forms partnership with CBIA. Greener nylon production could cut costs and pollution. Innovent Biologics, Inc. completes $100 million Series C financing funds to advance novel biologic pipeline and internal operations. PerkinElmer opens new medical laboratory in Suzhou, China. 3SBio acquires Sirton Pharmaceuticals SpA.

From zero to hero – Production of bio-based nylon from renewable resources using engineered Corynebacterium glutamicum

Polyamides are important industrial polymers. Currently, they are produced exclusively from petrochemical monomers. Herein, we report the production of a novel bio-nylon, PA5.10 through an integration of biological and chemical approaches. First, systems metabolic engineering of Corynebacterium glutamicum was used to create an effective microbial cell factory for the production of diaminopentane as the polymer building block. In this way, a hyper-producer, with a high diaminopentane yield of 41% in shake flask culture, was generated. Subsequent fed-batch production of C. glutamicum DAP-16 allowed a molar yield of 50%, a productivity of 2.2gL−1h−1, and a final titer of 88gL−1. The streamlined producer accumulated diaminopentane without generating any by-products. Solvent extraction from alkalized broth and two-step distillation provided highly pure diaminopentane (99.8%), which was then directly accessible for poly-condensation. Chemical polymerization with sebacic acid, a ten-carbon dicarboxylic acid derived from castor plant oil, yielded the bio-nylon, PA5.10. In pure form and reinforced with glass fibers, the novel 100% bio-polyamide achieved an excellent melting temperature and the mechanical strength of the well-established petrochemical polymers, PA6 and PA6.6. It even outperformed the oil-based products in terms of having a 6% lower density. It thus holds high promise for applications in energy-friendly transportation. The demonstration of a novel route for generation of bio-based nylon from renewable sources opens the way to production of sustainable bio-polymers with enhanced material properties and represents a milestone in industrial production.

Reconstructing suspended sediment mercury contamination of a steep, gravel-bed river using reservoir theory

We use sediment ages and mercury (Hg) concentrations to estimate past and future concentrations in the South River, Virginia, where Hg was released between 1930 and 1950 from a manufacturing process related to nylon production. In a previous study, along a 40 km (25 mi) reach, samples were collected from 26 of 54 fine-grained deposits that formed in the lee of large wood obstructions in the channel and analyzed for grain size, Hg concentration, and organic content. We also obtained radiometric dates from six deposits. To create a history that reflects the full concentration distribution (which contains concentrations as high as 900 mg/kg [900 ppm]), here, we treat the deposits as a single reservoir exchanging contaminated sediments with the overlying water column, and assume that the total sediment mass in storage and the distribution of sediment ages are time invariant. We use reservoir theory to reconstruct the annual history of Hg concentration on suspended sediment using data from our previous study and new results presented here. Many different reconstructed histories fit our data. To constrain results, we use information from a well-preserved core (and our estimate of the total mass of Hg stored in 2007) to specify the years associated with the peak concentration of 900 mg/kg. Our results indicate that around 850 kg (1874 lb) of Hg was stored in the deposits between 1955 and 1961, compared to only 80 kg (176 lb) today. Simulations of future Hg remediation suggest that 100-yr timescales will be needed for the South River to remove Hg-contaminated sediments from the channel perimeter through natural processes.

Nitrogen-Functionalized Ordered Mesoporous Carbons as Multifunctional Supports of Ultrasmall Pd Nanoparticles for Hydrogenation of Phenol

N-functionalized ordered mesoporous carbons could be readily obtained by post-synthesis treatment with nitrogen containing molecules to achieve materials with a nitrogen loading as high as 8.6 wt % and well preserved mesopore structure. Using NH3 as nitrogen source dramatically increased the Brunauer–Emmett–Teller (BET) surface area and pore volume of the resultant hybrid material; however, N-doping with melamine as a source resulted in the contrary results. The N-doped carbons were used as supports to immobilize small-sized Pd nanoparticles (PdNPs), which provided a unique platform to investigate the influence of metal nanoparticle size, mesostructural properties, and N-functionalized supports on the selective hydrogenation of phenol to cyclohexanone, an important intermediate in the production of nylon 6 and nylon 66 in the chemical industry. The catalyst with ultrasmall (about 1.2 nm) PdNPs gave the best reaction activity and selectivity under mild conditions. In addition, the present multifunctional c...

Fluid Phase Coexistence for the Oxidation of Cyclohexane in CO2 Expanded Liquids: COSMO‐SAC vs. Molecular Simulation

The oxidation of cyclohexane to cyclohexanol and cyclohexanone is an important industrial reaction and a key step in the nylon production chain. A novel route is to use supercritical carbon dioxide to expand the reactive liquid, which enhances the mobility of both the reactants and the products, to obtain a higher conversion rate and a better yield. However, only little experimental phase equilibrium data for design of carbon dioxide expanded oxidation processes is available, especially for a high pressure and multicomponent system. In previous works, we also performed experimental measurements. However, it would be a lot of work to measure all desired experimental data. Therefore, it would be interesting to examine the accuracy of prediction from molecular simulation and thermodynamic models. In this study, three theoretical approaches, i.e., molecular simulation, the Peng-Robinson equation of state (PR EOS), and COSMO-SAC, were investigated in a comprehensive study with respect to their predictive and descriptive capabilities for fluid phase coexistence data of an industrially important pentenary mixture. Overall, the PR EOS provides the poorest performance and the performance of molecular simulation and COSMO-SAC is good and very similar. Both molecular simulation and COSMOSAC are capable to predict multicomponent VLE with an excellent accuracy, if one state-independent binary parameter is introduced. Beside these satisfactory results, it was found that improvements are necessary, especially when no experimental binary data are available. In predictive mode, deviations up to 50% in terms of the vapor pressure or the Henry’s law constant were encountered for some systems. The presented data and models can be used for the optimization of the reaction conditions for the oxidation of cyclohexane in carbon dioxide expanded liquids.

Thermal, physical and mechanical properties of hydrogenated dimer acid-based Nylon 636/Nylon 66 copolymers

Hydrogenated dimer acid-based Nylon 636/Nylon 66 copolymers were synthesized by in situ polymerization. The effects of Nylon 66 contents on the copolymers were characterized by intrinsic viscosity measurements, attenuated total reflection-Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and mechanical tests. The results showed that incorporation of Nylon 66 into hydrogenated dimer acid-based Nylon had no significant effect on the glass transition or melting temperatures. However, the crystallization temperature, crystallinity degree and the maximum rate of decomposition temperature from derivative thermogravimetry measurements vary. Mechanical testing data revealed that with increasing Nylon 66 concentrations, the tensile strength of copolymers increased, while the elongation at break point and notched izod impact strength decreased. The physical and mechanical properties of HN-40, HN-50 and HN-60 are similar to those of the current PA11, PA1212, and PA1111 Nylon products.

Liquid–liquid equilibrium for the system water + 1,4-dioxane + cyclohexanol over the temperature range of 313.2–343.2 K

Cyclohexanol is an important chemical intermediate in nylon production. A new route, using a cosolvent for cyclohexanol production by direct hydration of cyclohexene in a reactive distillation column, was put forward. Liquid–liquid equilibrium (LLE) data for the ternary system water+1,4-dioxane+cyclohexanol were investigated experimentally at 1atm over the temperature range of (313.2–343.2)K. The Othmer–Tobias correlation was used to determine the reliability of the experimental tie-lines. The measured LLE data were compared with the values correlated by the nonrandom two-liquids (NRTL) and improved UNIQUAC models. It was found that both the NRTL and improved UNIQUAC models could provide good correlation results for this system. The NRTL and UNIQUAC equations were fitted to the experimental data with a root-mean-square deviation (RMSD%) of less than 0.19 and 0.41, respectively.

BIOAMBER FILES FOR PUBLIC OFFERING

RENEWABLE CHEMICALS start-up BioAmber hopes to raise up to $150 million in an initial public offering (IPO) of stock. The firm’s first product is succinic acid, a fermentation-derived intermediate that several other companies are also developing. BioAmber says its industrial biotechnology process yields cost-competitive replacements for petroleum-derived chemicals. Succinic acid can be a raw material for plastics, food additives, and personal care ingredients and a building block for other intermediates including 1,4-butanediol (BDO). BioAmber says it is also developing biobased adipic acid and caprolactam, both used in the production of nylon. In its filing with the Securities & Exchange Commission, BioAmber says it has made 221 metric tons of biobased succinic acid at its facility in Pomacle, France, but has yet to book any sales. Instead, the firm touts its strategic partnerships with potential succinic acid buyers including Mitsubishi Chemical, Lanxess, and Solvay. To achieve sales, BioAmber will need...

Causation, Evidence, Argumentation Theory: The Case of Pleural Mesothelioma

Which evidence for causation? Mr. X, an inhabitant of the city V, is diagnosed with a disease, m. It has a curious name, pleural mesothelioma, but it's one of those that leave no escape. You can live, yes you can do this for a short time, at least, but you have to spend too much time to fix your stuff, waiting for the “almost” certain death. Damned disease. Breathing is possible, this is not the question. Breathing is difficult, this may be the question. What does he breathe? Mr. X has a job. Everyone has a job in the city V. But his job is particular. He works in the company M which produces nylon fibres. About three thousand persons work with him in the same company. Maybe the city V should build a monument to the company M. It employs all, at least all those who needed a job. Oh yes, because everyone would like to work outdoors. It is also true that everyone would like to have a job, provided that this is necessary. My grandmother used to say that if you feel good, you can have fun, without working. She has worked a lifetime, apparently she was not so good. In general, however, in the city V, it is not so easy to survive; what do you think about to live in it? We need, in short, going to go and work in the little factory of fibres, which are a bit heavy. Of course, not everyone in the factory work in the same department, there are those who work in the office and there are those, however, who work in the workplaces Y, Z, W. Nylon production processes have one rather boring characteristic: they require manufacturing processes carried out in heated environments, with tubes and machines capable of supporting the “ torrid temperature.” No problem, we would say. Who loves low temperatures? Not many, it is believed, and in any case in the area of V most people dreams of tropical beaches, there is enough cold to bear in V area. To avoid those hot causes damages, in the premises of M, there is a department of insulation, a bad word to say that there are produced coatings, especially for the protection of pipelines. Is that all? Only coatings? The question is that the substance used to make clothes to pipelines is one of those who are hard to bear, if you are not a pipeline and if you find yourself to be an ordinary mortal: asbestos, A. Why asbestos? The decision to continue using asbestos to insulate the cooling pipes pertaining to the high temperature nylon processing, is very simple: it is cheaper than glass fibre or other non-cancerous or less cancerous materials, used in other plants of the same M. In Verbania are employed 3600 workers who have not been informed on the risks of diseases related to asbestos “used in a massive way” and “ no serious and radical change in the risk situation” is implemented.

Migration of Monomers and Primary Aromatic Amines from Nylon Products

Migration of 2 kinds of monomer and 21 kinds of primary aromatic amines (PAAs) from 21 kinds of nylon products such as turners, ladles and wrap film were determined. Samples were classified as regards materials by mean of pyrolysis-GC/MS. One sample was classified as nylon 6, 15 samples as nylon 66 and three samples as nylon 6/66 copolymers, while two samples were laminate of nylon 6 with polyethylene or polypropylene. All of the nylon 66 samples contained a small amount of ε-caprolactam (CPL), which is the nylon 6 monomer. Migration levels of monomers and PAAs at 60°C for 30 min into 20% ethanol were measured by LC/MS/MS. CPL was detected at the level of 0.015-38 µg/mL from all samples, excluding one wrap film sample, and 1,6-hexamethylenediamine was detected at the level of 0.002-0.013 µg/mL from all nylon 66 samples and one nylon 6/66 sample. In addition, 0.006-4.3 µg/mL of 4,4'-diaminodiphenylmethane from three samples, 0.032-0.23 µg/mL of aniline from four samples, 0.001 µg/mL of 4-chloroaniline from two samples, and 0.002 µg/mL of 2-toluidine and 0.066 mg/mL of 1-naphthylamine from one sample each were detected. The migration levels at 95 or 121°C were about 3 and 10 times the 60°C levels, respectively.

Preparation and properties of (epoxy resin)/(nylon 6,6 oligomer) blends

A series of polymer alloys based on different compositions of Nylon 6,6 oligomers (NYL66Oґs) and epoxy resin have been prepared. The oligomer was extracted from the waste residues of the industrial production of nylon 6,6 and was dissolved in the epoxy resin. The mixture was crosslinked at 333 K using dodecenylsuccinic anhydre (DDSA) as a curing agent. The tensile strength and flexural modulus were found to increase with the addition of NYLO66O up to a maximum value of 2 wt % oligomer content. Both, the tensile and impact strength show a maximum increase due to the addition of 35 wt % NYLO66O. The compressive strength testing revealed a considerable increase, up to 87 %, over that of the neat epoxy with the addition of 1 wt % NYLO66O. An interesting relationship between the mechanical properties and the developed morphology of the blends has been found.