Faramarzi, Leila; Kontogeorgis, Georgios; Michelsen, Michael Locht;
The rate-based steady-state model proposed by Gabrielsen et al. (Gabrielsen, J.; Michelsen, M. L.; Kontogeorgis, G. M.; Stenby, E. H. AIChE J. 2006, 52, 10, 3443-3451) for the design of the CO2-2-amino-2-methylpropanol absorbers is adopted and improved for the design of the CO2-monoethanolamine a......, and their impact on the model's prediction is compared. The model has been successfully applied to CO2 absorber packed columns and validated against pilot plant data with good agreement.......The rate-based steady-state model proposed by Gabrielsen et al. (Gabrielsen, J.; Michelsen, M. L.; Kontogeorgis, G. M.; Stenby, E. H. AIChE J. 2006, 52, 10, 3443-3451) for the design of the CO2-2-amino-2-methylpropanol absorbers is adopted and improved for the design of the CO2-monoethanolamine...
Holm, E S; Schäfer, A; Koch, A G; Petersen, M A
Sliced saveloy samples were inoculated with monocultures of four potential spoilage bacteria and studied during a four week storage period. The objective was to investigate the resulting changes in the composition of Volatile Organic Compounds (VOCs) and the sensory quality of the product. Based on the sensory scores and the VOC composition Brochothrix thermosphacta, Chryseomonas luteola and Carnobacterium maltaromaticum were found to have a high spoilage potential in saveloy samples subjected to consumer simulated storage during the fourth week. Inoculation with Leuconostoc carnosum only resulted in a low level of spoilage. The sensory changes in the saveloy samples were modeled based on the VOC composition using Partial Least Squares Regression. The changes in the six sensory descriptors were closely related to the amount of diacetyl, acetoin, 2- and 3-methylbutanol, 2- and 3-methylbutanal and 2-methylpropanol found in the samples. These compounds are therefore potentially important for the shelf-life of sliced saveloy. PMID:23261532
The geometric structure and isomerization of the 2-methylpropionyl chloride molecule in the ground electronic state in gaseous phase was studied using Ab initio methods (RHF, DFT, MP2 and QCISD). The potential energy surface (PES) and regions corresponding to transitions between conformers by the rotation of the isopropyl and two methyl groups was examined in one-dimensional approximation. The influence of the atomic orbital basis set and the method on the accuracy of the calculation of PES characteristics was considered. The calculation of the energy differences of conformers (DE) using reasonable basis sets provides values in good agreement with experimental results. The values of the potential barriers to gauche → gauche and cis → gauche transitions, and also the barrier of isopropyl and two methyl groups were compared with the same values for similar molecules as 2-methylpropanol and 2-methylpropionyl fluoride. (author)
Sun, Shu Yang; Jiang, Wen Guang; Zhao, Yu Ping
Tart cherries of 'Early Richmond', widely grown in Shandong (China), were fermented with six different Saccharomyces cerevisiae strains (BM4×4, RA17, RC212, D254, D21 and GRE) to elucidate their influence on the production of volatiles and polyphenols. Acetic acid and 3-methylbutanol were found in the highest concentrations among all identified volatiles with all six yeast strains, followed by 2-methylpropanol and ethyl lactate. RA17 and GRE cherry wines were characterised by a higher amount of esters and acids. D254 wine contained a higher concentration of alcohols. With respect to polyphenols, five phenolic acids and four anthocyanins were identified among all tested samples, with chlorogenic and neochlorogenic acids, cyanidin 3-glucosylrutinoside and cyanidin 3-rutinoside being the major compounds. When using principal component analysis to classify the cherry wines according to the volatiles and polyphenols, they were divided into three groups: (1) RA17 and GRE, (2) RC212 and D254 and (3) BM4×4 and D21. PMID:23140699