On the optimization of caprolactam polymerization

Reimschuessel, H. K.; Nagasubramanian, K.

doi:10.1016/0009-2509(72)80023-x

Cited by 60 publications

(49 citation statements)

References 9 publications

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“…For the constants of Tai et al, 9 the enthalpy balance (#1 / #2 Å #3) closes to within 16 cal/mol and the entropy balance to within 0.005 cal/mol/ЊC. The constants of Reimschuessel et al 10 also balance closely. However, the situa-…”

Section: Introductionmentioning

confidence: 71%

“…One is very tightly bound with a dielectric used to calculate K add in eq. (10). Values for the constant like that of ice; this state is similar to equilibrium model parameters are summarized in that discussed earlier for nylon (Fig.…”

Section: Results Of Model-equilibriummentioning

confidence: 95%

“…The kinetic model presented here will assume instead that all reaction is acid catalyzed Furthermore, as mentioned above, by knowing DH 1 / DH 2 Å DH 3 with reaction numbers defined in Figure 1, the model, with coefficients from Table II, predicts an enthalpy of ring opening of 04.4 kcal/mol. By contrast, Tai et al 9 and Reimschuessel et al 10 found enthalpies of ring opening of 1.9 and 2.1 kcal/mol, respectively. The ring opening enthalpy of this work (04.4 kcal/mol) compares reasonably well with the experimental value of 05.7 kcal/mol [Strepikheev et al and eq.…”

Section: Figurementioning

confidence: 85%

“…9,10 The constants of Tai et al 9 are currently the standard for modeling nylon 6 melt reactions (Table I).…”

Section: Estimation Methodsmentioning

confidence: 99%

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A comprehensive model for nylon melt equilibria and kinetics

Mallon

Ray

1998

J. Appl. Polym. Sci.

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ABSTRACT:A model for handling the effect of water on nylon equilibria and kinetics has been developed and tested. Observed variations in the equilibria and kinetics are attributed to microscopic phenomena, not an empirical expression. The equilibrium variation is modeled based on two states of water in the nylon melt, and the kinetic variation is modeled as due to a changing dielectric constant. All reactions are assumed to be acid catalyzed. Results are good at water to polymer ratios ranging from 0.01 to 30 and from temperatures from 200 to 280ЊC. The model framework also allowed the calculation of interchange rates and ring oligomer concentrations. The model is compared with published data and other proposed models.

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Section: Introductionmentioning

confidence: 71%

Section: Results Of Model-equilibriummentioning

confidence: 95%

Section: Figurementioning

confidence: 85%

“…9,10 The constants of Tai et al 9 are currently the standard for modeling nylon 6 melt reactions (Table I).…”

Section: Estimation Methodsmentioning

confidence: 99%

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A comprehensive model for nylon melt equilibria and kinetics

Mallon

Ray

1998

J. Appl. Polym. Sci.

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“…CL is converted into the polymer by the mechanism of hydrolytic polymerization [26,[34][35][36][37][38] ).…”

Section: Kinetics Of Hydrolytic Polymerization Of Caprolactam In the mentioning

confidence: 99%

Solid-phase synthesis of polyamide-6

Mizerovskii

Bazarov

2006

Fibre Chem

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678.675:66 09Solid-phase synthesis of PA-6, simultaneously discovered with the reaction of conversion of CL into a polymer and of practical interest primarily as a method for obtaining a polymer constructed of strictly linear macromolecules and containing a minimum amount of CL and especially cyclic oligomers, is not solid-phase in the generally understood meaning of this term. This essentially concerns a set of liquid-phase reactions which differ from ordinary reactions due to the fact that some of the participants and primarily the solvent molecules, which the kinetic segments of transfer chains act as, are free of translational mobility, and the entire reaction volume is in a stressed state due to differences in the coefficients of thermal expansion of amorphous and crystalline microregions of the polymer and the developed process of additional crystallization. The presence of an important reaction volume which persists in a relatively wide temperature range and the very large amplitudes of vibrations of translationally immobile reactive groups makes the process kinetically more advantageous than solid-phase polycondensation of monomeric ε-aminocaproic acid.Low-temperature hydrolytic polymerization of caprolactam (CL) accompanied by crystallization of the polycaproamide formed (PA-6) and the subsequent evolution of the reaction as formally solid-phase was described for the first time in the patent [1] obtained by Hubert and Ludewig in Germany in 1939. The possibility of this process also follows from the sense of the patents [2, 3] obtained by Schlack in Germany in 1938 and in the US in 1941.In 1942, this version of synthesis of PA-6 was used by Staudinger and Warder .4, p. 19/] for obtaining a polymer of rigorously linear structure. However, it has not yet been implemented on the industrial scale due to the lack of an acceptable method of giving the solid polymer a shape convenient for processing it into yarn [5, p. 90].The studies conducted in [1959][1960][1961][1962][1963][1964][1965][1966][1967][1968][1969][1970][1971][1972] showed that Klares ideas [5, p. 90] concerning solid-phase synthesis of PA-6 from ε-aminocaproic acid were also practically unrealizable.The low rate of the process and mainly the very narrow temperature range in which the first stage can take place conversion of the monomer into an oligomer are a stumbling block in this case.Moreover, the research conducted in this period on solid-phase additional polycondensation of demonomerized PA-6 obtained by purely liquid-phase hydrolytic polymerization of CL to significantly increase its molecular weight and correspondingly the physicomechanical indexes of the spun yarns allowed Kudryavtsev, Nosov, and Volokhina to conclude in the second half of the 70s that the technical and economic advantages of solid-phase complete polyamidation of such PA-6 are obvious, but the process and implementation of the process require further development [6].Today solid-phase additional polycondensation is widely used in synthesis of high-molecular-weight polyethy...

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Multiobjective optimization of an industrial nylon-6 semibatch reactor system using genetic algorithm

Gupta

1999

J. Appl. Polym. Sci.

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Multiobjective Pareto optimal solutions for three different grades of nylon-6 produced in an industrial semibatch reactor are obtained by using the adapted Nondominated Sorting Genetic Algorithm (adapted NSGA). The two objective functions minimized are the total reaction time and the concentration of undesirable cyclic dimer in the product, while simultaneously attaining desired values of the monomer conversion and the number average chain length. The control variables used are the fractional valve opening f(t) and the jacket fluid temperature T J . The study shows a marked improvement over current industrial operation. It is found that the optimal values of the cyclic dimer concentration in the product are worse (higher) when the reactorcontrol valve system is studied than when the reactor is considered alone. This is because the control valve leads to additional constraints. The technique used is quite general and can be used to study other reactor systems as well.

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On the optimization of caprolactam polymerization

Cited by 60 publications

References 9 publications

A comprehensive model for nylon melt equilibria and kinetics

A comprehensive model for nylon melt equilibria and kinetics

Solid-phase synthesis of polyamide-6

Multiobjective optimization of an industrial nylon-6 semibatch reactor system using genetic algorithm

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