31 KB233 KB28 KB199820252006Dill, Ken A.Hribar, Barbaraštevilka:3letnik:537 stranistr. 257-263ISSN:1318-0207COBISSID:27964165URN:URN:NBN:SI:doc-M9ISHZUPenSlovensko kemijsko društvoActa chimica slovenicaalkoholidimenzioniranjefizikalna kemijametoda Monte CarlomodeliMonte Carlo methodračunalniške simulacijeraztopinetermodinamikaModeling simple alcohols in two dimensions|The alcohol-water mixtures were studied within a two-dimensional model. The MB model was used for modeling water and alcohol molecules were modeled as non-flexible chains consisting of two-dimensional Lennard-Jones disks with the first disk having two hydrogen-bonding arms. The model was explored using NPT Monte Carlo computer simulation. The results were compared with the experimental thermodynamic properties of methanol-water mixtures. The qualitative agreement was obtained for the excess volume of mixing, but due tothe surface-volume effects not properly captured by two dimensional models, the excess enthalpy of mixing cannot be represented correctly by this model. Further, we studied the transfer of a single alcohol molecule into water, focusing on the trends exhibited by the methanol, ethanol, propanol, n-butanolseries. While small alcohol molecules show the correct trend the flexibility of the alcohol molecules should be taken into account to improve the agreement for higher alcoholsV članku smo uporabili preprost dvodimenzionalni model za studij mešanic alkoholov in vode. Za molekule vode smo uporabili MB model, molekule alkoholov pa smo ponazorili kot nefleksibilne verige sestavljene iz dvodimenzionalnih Lennard-Jonesovih diskov, pri čemer je imel prvi disk v verigi dve roki za tvorbo vodikovih vezi. Model smo študirali z računalnisko simulacijo Monte Carlo, in sicer v NPT ansamblu. Rezultate smo primerjali z eksperimentalnimi termodinamičnimi podatki za mešanice metanol-voda. Presežni volumni mešanja dobljeni za model se kvalitativno ujemajo z eksperimentalnimi podatki, vendar zaradi reducirane dimenzionalnosti model napačno opise presežne entalpije mešanja. V nadaljevanju smo študirali termodinamiko prenosa molekule alkohola v vodo, pri čemer nas je zanimal predvsem trend, ki ga kaže vrsta metanol, etanol, propanol, n-butanol. V primeru nižjih alkoholov model kvalitativno pravilno opiše termodinamiko hidratacije alkoholov, pri višjih alkoholih pa bi bilo za boljše ujemanje potrebno upoštevati tudi fleksibilnost molekul alkoholaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaSlovensko kemijsko društvo