Computer-aided molecular design of alternative solvents based on phase equilibrium synergism in mixtures

A systematic methodology is proposed that finds binary azeotropic mixtures as new alternative solvents for the extraction process of volatile aroma molecules widely used in perfume and cosmetic industries. We investigated the use of the reverse engineering approach with Computer Aided Product Design (CAPD) instead of the traditional ‘trial and error’ approach. First, the design problem is defined from the real functionalities of the classical solvents. They are translated into physicochemical properties and the bound values for each property are defined. The reverse engineering method coupled to CAPD consists in using optimization techniques for building molecular structures that match as best as possible the complete set of target physicochemical properties, thus defining for each candidate a performance index. Property values are evaluated by using group contribution methods of each molecular structure generated by CAPD tool or by using database values. Acknowledging the contradictory relationship between two selected physicochemical properties i.e, low boiling temperature and high flash point which is rarely found in pure components, binary azeotropic mixtures were studied in order to enhance the global performance of solvent candidates. Dimethyl carbonate (DMC) is an existing solvent for the extraction of odorous molecules from plants that exhibits a good ratio between the boiling temperature and the flash point. It is selected as the key component for designing binary azeotropic mixtures. DMC. The global performance of the binary azeotropic mixtures was verified by means of calculations of the vapour-liquid equilibrium and liquid – liquid equilibrium using Modified UNIFAC method as thermodynamic method

Modelling and experimental validation of dimethyl carbonate solvent recovery from an aroma mixture by batch distillation

Modelling and experimental validation of solvent recovery from an aroma mixture by batch distillation process is presented, with particular emphasis of the effect of the prediction of the physicochemical properties and the phase equilibrium data on the content of the aroma compounds in the distillate cuts. The illustrative case study refers to an industrial batch distillation to recover dimethyl carbonate (DMC) from an extract generated by a solvent extraction process involving variable natural raw materials for tailored perfume and fragrance applications. Due to the high number of aroma compounds in natural extracts, a synthetic mixture containing six target aroma compounds (α-pinene, eucalyptol, linalool, cis-3-hexenol, fenchone and benzyl acetate) was mixed with DMC for the modelling and experimental studies of the batch distillation process. The methodology is tested through the simulation of the process with BatchColumn® software. As physicochemical properties of the aroma compounds and the vapour–liquid equilibrium (VLE) of all involved mixtures are required for simulation study, group contribution methods are used to predict missing properties such as vapour pressure, vaporisation enthalpy and liquid and vapour heat capacities. For VLE calculation, the modified UNIFAC group contribution method is considered and new binary interaction parameters for the main groups COO and CH2O are regressed from experimental data. Simulation results are in good agreement with experiments carried out in a fully automated batch distillation column at 15 kPa and help optimise the industrial process operation. The proposed methodology can be applied for the design of other solvent recovery process in fragrance industry

Dimethylcarbonate as a new green solvent for fragrant extracts: Eextraction and recovery processes

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Diagnosis of Constitutional Mismatch Repair-deficiency Syndrome Based on Microsatellite Instability and Lymphocyte Tolerance to Methylating Agents

Patients with bi-allelic germline mutations in mismatch repair (MMR) genes (MLH1, MSH2, MSH6, or PMS2) develop a rare but severe variant of Lynch syndrome called constitutional MMR deficiency (CMMRD). This syndrome is characterized by early-onset colorectal cancers, lymphomas or leukemias, and brain tumors. There is no satisfactory method for diagnosis of CMMRD because screens for mutations in MMR genes are non-informative for 30% of patients. MMR-deficient cancer cells are resistant to genotoxic agents and have microsatellite instability (MSI), due to accumulation of errors in repetitive DNA sequences. We investigated whether these features could be used to identify patients with CMMRD.publisher: Elsevier articletitle: Diagnosis of Constitutional Mismatch Repair-Deficiency Syndrome Based on Microsatellite Instability and Lymphocyte Tolerance to Methylating Agents journaltitle: Gastroenterology articlelink: http://dx.doi.org/10.1053/j.gastro.2015.06.013 content_type: article copyright: Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.status: publishe