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Journal ArticleDOI

Separation of the isomeric long-chain aldehydes dodecanal/2-methylundecanal via layer melt crystallization

30 Jul 2012-Chemical Engineering Science (Pergamon)-Vol. 77, pp 71-77
TL;DR: In this paper, the feasibility of the purification of dodecanal from the isomeric long-chain mixture of aldehydes with melt crystallization was evaluated using differential scanning calorimetry.
About: This article is published in Chemical Engineering Science.The article was published on 2012-07-30. It has received 29 citations till now. The article focuses on the topics: Crystallization & Dodecanal.
Citations
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Journal ArticleDOI
TL;DR: A collection of phase change enthalpies of organic molecules including fusion, vaporization, and sublimation enthalphies for organometallic, ionic liquids, and a few inorganic compounds can be found in this paper.
Abstract: The second part of this compendium concludes with a collection of phase change enthalpies of organic molecules inclusive of C11–C192 reported over the period 1880–2015. Also included are phase change enthalpies including fusion, vaporization, and sublimation enthalpies for organometallic, ionic liquids, and a few inorganic compounds. Paper I of this compendium, published separately, includes organic compounds from C1 to C10 and describes a group additivity method for evaluating solid, liquid, and gas phase heat capacities as well as temperature adjustments of phase changes. Paper II of this compendium also includes an updated version of a group additivity method for evaluating total phase change entropies which together with the fusion temperature can be useful in estimating total phase change enthalpies. Other uses include application in identifying potential substances that either form liquid or plastic crystals or exhibit additional phase changes such as undetected solid–solid transitions or behave ani...

107 citations

Journal ArticleDOI
TL;DR: In this article, a systematic optimization procedure based on a large scale optimization problem constrained by a system of differential algebraic equations (DAE) is presented to derive the process-wide optimal reaction concept in combination with optimal process parameters.

56 citations

Journal ArticleDOI
TL;DR: A two-stage formulation where the operational parameters can be adapted to the realization of the uncertainty while the design parameters are the first-stage decisions to adequately deal with uncertainty in the early phase of process design.

38 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a four-step design method which can be applied in early process development stages when not all model parameters are available, and demonstrated the feasibility of the approach with the separation of a binary mixture of isomeric aldehydes.
Abstract: Hybrid separations combining distillations and crystallisations have a significant potential for process intensification. To address the large number of degrees of freedom in the design of hybrid separations, a three-step approach is utilised. However, it can only be applied if all parameters for the rigorous modelling of crystallisation and cost functions are known a priori, which is often not the case. In this paper, we propose a four-step design method which can be applied in early process development stages when not all model parameters are available. In the first step, different process variants are generated. In the second step, the variants are evaluated using rigorous models, wherein the unknown model parameters are varied to quantify their influence on the process performance. If hybrid separations appear to be compatible, experiments are performed to determine the unknown parameters in the third step. In the last step, an optimisation is performed to find the optimal process, when necessary in dependence of unknown cost parameters. The developed tools and the feasibility of the approach are illustrated with the separation of a binary mixture of long-chain isomeric aldehydes.

38 citations

Journal ArticleDOI
TL;DR: In this article, a review of the research progress and process model development of the key processes (crystal layer growth and impurity distribution) involved in layer melt crystallization is presented.
Abstract: Layer melt crystallization has been widely utilized in numerous chemical industries because of its high selectivity for pure products, low energy consumption, and the convenience to industrialization. This review will lay out the research progress and process model development of the key processes (crystal layer growth and impurity distribution) involved in layer melt crystallization. First, the nucleation mechanism, the preparation approaches of the initial crystal layer, and classic experimental configurations are illustrated. Second, modeling approaches are outlined to release the progress of separation effect evaluation, parameter optimization, and sweating process simulation in layer melt crystallization. Novel theories (fractal, porous media, and so on) and technologies (gradient freezing, sonocrystallization, and so forth) with suitable interpretation are potential solutions for the shortcomings of the current process research. Consequently, application areas related to layer melt crystallization a...

37 citations

References
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Book
01 Jan 1999

1,149 citations

MonographDOI
27 Sep 2007
TL;DR: Additives and crystallization processes, Additives and crystalization processes as discussed by the authors, additive and crystallisation processes, کتابخانه الکرونیک و دیجیتال - آذرسا
Abstract: Additives and crystallization processes , Additives and crystallization processes , کتابخانه الکترونیک و دیجیتال - آذرسا

210 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used a differential scanning calorimeter (DSC) to measure solubility in microsamples employing a DSC for several aqueous and nonaqueous systems.
Abstract: The measurement of solubility in microsamples employing a differential scanning calorimeter (DSC) has been evaluated for several aqueous and nonaqueous systems: substance A in acetonitrile, (RS)-mandelic acid, (S)-mandelic acid, adipic acid, diphenhydramine HCl, α-glycine, and terephthalic acid in water, (RS)-mandelic acid and β-succinic acid in ethanol and methanol, and adipic acid in ethanol. This technique requires samples in the range of milligrams and can be used at high temperatures and pressures. Results show that the solubility data of most compounds studied using this technique are within 5% of solubility data obtained from the literature. Factors that influence solubility measurement by DSC were examined along with methods to minimize associated errors.

102 citations

Journal ArticleDOI
TL;DR: In this article, the rate constants for chain propagation (kp) and chain termination (2kt) were investigated for aldehydes in chlorobenzene at 0 °C, and it was concluded that peroxy radicals derived from aldehyde are considerably more reactive in hydrogen atom abstraction from hydrocarbons.
Abstract: The oxidations of acetaldehyde, heptanal, octanal, cyclohexanecarboxaldehyde, pivaldehyde, and benzaldehyde in chlorobenzene at 0 °C have been studied. These aldehydes oxidize at similar rates under similar conditions because there are compensating changes in the rate constants for chain propagation (kp) and chain termination (2kt). The termination rate constants increase from ∼7 × 106 M−1 s−1 for pivaldehyde and cyclohexanecarboxaldehyde to ∼2 × 109 M−1 s−1 for benzaldehyde. The propagation rate constants increase from ∼1 × 103 M−1 s−1 for pivaldehyde to ∼1 × 104 M−1 s−1 for benzaldehyde.The rate of oxidation of the aldehydes was decreased by the addition of 1,4-cyclohexadiene, tetralin, tetralin hydroperoxide, cumene, cumene hydroperoxide, t-butyl hydroperoxide, and 2,6-di-t-butyl-4-methylphenol. As a result of product analysis and absolute rate constant measurements, it is concluded that the peroxy radicals derived from aldehydes are considerably more reactive in hydrogen atom abstraction from hydrocar...

67 citations

Reference BookDOI
28 Dec 2020
TL;DR: Melt crystallization as discussed by the authors is an important chemical process technology and is one of the few routes that appear to be feasible for purifying starter materials for high-tech polymers.
Abstract: From the Author's Preface: There is a growing demand for ultrapure organic compounds such as fine chemicals, pharmaceuticals, and basic materials for use in the polymer industry. . . . In quite a number of cases, it is difficult or impossible to manufacture ultrapure organics efficiently using conventional separation techniques such as distillation. Moreover, conventional techniques usually require large amounts of energy. To improve the purification efficiency of organics, special techniques based on crystallization from the melt have been developed. Melt crystallization meets industry's need for a highly selective separation process for organic compounds which operates at low enough temperatures to prevent thermal degradation. Melt crystallization processes have the added advantage that they are energy-efficient and ecologically sound. Melt crystallization techniques appear to be particularly promising for upgrading organic materials and are one of the few routes that appear to be feasible for purifying starter materials for high-tech polymers. The aim of this book is to provide basic information on melt crystallization technology. . . . This monograph consists of three parts: 1. basic principles, 2. process options, and 3. technical equipment and applicability. This new book is the first unified guide and reference to an important chemical process technology. It is comprehensive and organized for easy reference. More than 150 diagrammatic representations, flow charts and photographs illustrate equipment and processes. More than 40 tables provide useful reference data.

51 citations