953. The equilibrium in the system : water–6-hexanolactam (Îµ-caprolactam)

Meggy, A. B.

doi:10.1039/jr9560004876

Cited by 8 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Table 7 , they used these data to estimate 20 kinetic parameters (including 10 activation energies) and 10 equilibrium parameters (including 5 reaction enthalpies). Parameter values estimated by other research groups (using smaller data sets or unpublished data) are also shown in Table 7 11,14–16,18,24,25,32,35,42,45–547 are similar for different research groups (e.g., the activation energy estimate of 78.7 kJ mol −1 for R1 reported by Arai et al11 is similar to 78.5 kJ mol −1 reported by Reimschussel et al,45 other parameter estimates differ by orders of magnitude between research groups.…”

Section: Reaction Mechanism and Literature Reviewsupporting

confidence: 62%

Improved Kinetic Rate Constants for Nylon 6, Nylon 6,6, and Nylon 6/6,6 Copolymer

Liu

McAuley

2019

Macro Reaction Engineering

View full text Add to dashboard Cite

Nylon 6 and 6,6 literature data are collected over a wide range of water concentrations and temperatures (0 ≤ [W]0 ≤ 40.8 wt%, 200 ≤ T ≤300 °C) and used to fit parameters in an updated batch reactor model. The resulting copolymerization model uses side reactions to account for the complex influence of water on kinetics and reaction equilibria. The proposed parameter estimates result in a significant improvement in the fit to the data, corresponding to a 73% reduction in the weighted‐least‐squares objective function compared to when the parameters of Arai et al. are used. Copolymerization simulations are conducted at industrially relevant conditions, shedding light on the complex influence of water and on the potential to include waste nylon 6 cyclic dimer in the feedstock. The model and parameter estimates will be helpful in future models of nylon 6/6,6 copolymerization in continuous reactor systems.

show abstract

Section: Reaction Mechanism and Literature Reviewsupporting

confidence: 62%

Improved Kinetic Rate Constants for Nylon 6, Nylon 6,6, and Nylon 6/6,6 Copolymer

Liu

McAuley

2019

Macro Reaction Engineering

View full text Add to dashboard Cite

show abstract

“…The resulting models provide an excellent fit to the data for the apparent equilibrium constant K 1a for caprolactam hydrolysis (which increases with water concentration and with temperature). The main contribution of this study is the model in Equation for K 2a , the apparent equilibrium constant for polycondensation, which exhibits complex behavior . The proposed model predicts the observed initial increase in K 2a at low water concentrations followed by the observed decrease in K 2a at high water concentrations.…”

Section: Discussionmentioning

confidence: 94%

“…The idealized equilibrium constants in Equations – depend on temperature according to

K_{i} = \exp (- \frac{normalΔ H_{i}}{R T} + \frac{normalΔ S_{i}}{R})

where Δ H i and Δ S i are the enthalpy and entropy changes, respectively, of the i th reaction. Table 3 provides values of Δ H i and Δ S i that have been fitted from equilibrium and/or dynamic data by various research groups . The values of Arai et al.…”

Section: Reaction Mechanism and Literature Reviewmentioning

confidence: 99%

“…fitted their parameter values using low water concentrations (0.8–2.1 wt%), which are typical during nylon 6 production. Several studies have shown that the apparent equilibrium constant for polycondensation reaction R2 depends not only on temperature but also on water concentration . For example, Figure 1 shows apparent equilibrium constant values calculated by Wiloth and by Giori and Hayes using nylon 6 data collected at 220 and 240 °C over a wide range of water concentrations .…”

Section: Reaction Mechanism and Literature Reviewmentioning

confidence: 99%

“…Knowledge of the equilibrium behavior of the reactions in Table is important for optimizing operating conditions in batch and continuous nylon reactor systems. It has long been known that equilibrium behavior during both nylon 6 and nylon 6,6 production depends in a complex way on the water concentration . The objectives of the current study are to: i) review and collect the literature data for nylon 6 and 6,6 reaction equilibria and ii) to develop reliable semi‐empirical equations (and corresponding parameter values) to model the equilibrium behavior of the reactions in Table .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling Equilibrium Behavior of Nylon 6, Nylon 6,6 and Nylon 6/6,6 Copolymer

Liu

Marchildon

McAuley

2019

Macro Reaction Engineering

View full text Add to dashboard Cite

Nylon 6 and nylon 6,6 reaction equilibria depend in a complex way on water concentration and temperature. For example, data sets from six research groups reveal that the apparent equilibrium constant for polycondensation increases with water at low water concentrations, reaches a maximum, and then decreases as the water concentration rises further. In this article, semi‐empirical expressions are proposed to describe the experimentally observed equilibrium behavior for the five main reactions that occur during nylon 6 and nylon 6,6 polymerization. Nine side reactions involving amidine ends, cyclopentanone ends, and hydrated carboxyl ends are used to develop expressions that account for the influence of both water and temperature on these equilibrium constants. Excellent fit to the data, over the entire range of the available nylon 6 and nylon 6,6 literature data, suggests that the proposed equations will be helpful for modeling reaction equilibria for nylon 6/6,6 copolymerization.

show abstract

Studies on polycondensation reactions of nylon salt. I. The equilibrium in the system of polyhexamethylene adipamide and water

Ogata

1960

Makromol. Chem.

View full text Add to dashboard Cite

The solubility of water in molten polyhexamethylene adipamide (nylon 66) has been measured in urder to investigate the equilibrium in the system of nylon 66 and water. The solubility of water n, (mole/mole of fundamental structural unit) increases with the rise of the vapour pressure p (mm. Hg) of water and HENRY'S law holds well within the range of water contents of less than 0.1 yo. The following equation is obtained.log (nw/p) = 3050/T -10.09Under the same vapour pressure of water, the number of amino groups in the polymer increases markedly with the rise of temperature, while that of carboxyl groups decreases. The equilibrium constant K of the condensation reaction between the linear polymers can be expressed in the following equation.The relationship between the number average degree of polymerigation Pn and p can be expressed as follows: log P, = 0.73 + 1375/T -'/2. log p ZUSAMMENFASSUNG: Um das Gleichgewicht des Systems Nylon 66-Wasser zu untersuchen, wurde die Loslichkeit von Wasser in geschmolzenem Polyhexamethylenadipinsaureamid (Nylon 66) gemessen. Die Loslichkeit des Wassers nw (Mol pro Mol des Grundbausteins) nimmt mit steigendem Wasserdampfdruck p (mm Hg) zu und das HENRYsahe Gesetz gilt fur Ansatze mit einem Wassergehalt unter 0,l yo. Hierfiir gilt die Formel log (nw/p) = 3050/T-10,09 Bei konstantem Wasserdampfdruck nimmt mit steigender Temperatur die Zahl der Aminogruppen im Polymeren merklich zu, wahrend sich die Zahl der Carboxylgruppen vermindert. Die Gleichgewichtskonstante K der Kondensationsreaktion zwischen den Kettenmolekiilen kann in folgender Formel ausgedriickt werden: log K = 5800/T -8,32 Der Abhiingigkeit des Zahlenmittels des Polymerisationsgrads Pn von p ist: log P, = 0,73+ 1375/T-1'/,*log p 3, H. YUMOTO, Bull. chem. SOC. Japan 28 (1955) 94 and 101.

show abstract

953. The equilibrium in the system : water–6-hexanolactam (Îµ-caprolactam)

Cited by 8 publications

References 0 publications

Improved Kinetic Rate Constants for Nylon 6, Nylon 6,6, and Nylon 6/6,6 Copolymer

Improved Kinetic Rate Constants for Nylon 6, Nylon 6,6, and Nylon 6/6,6 Copolymer

Modeling Equilibrium Behavior of Nylon 6, Nylon 6,6 and Nylon 6/6,6 Copolymer

Studies on polycondensation reactions of nylon salt. I. The equilibrium in the system of polyhexamethylene adipamide and water

Contact Info

Product

Resources

About