Phase behavior of methane with carboxylic acids

Shy, Der Shin; Yau, Jun Shun; Tsai, Fuan Nan

doi:10.1021/je00009a027

Cited by 3 publications

(2 citation statements)

References 8 publications

(11 reference statements)

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“…In our data collection, an electronic database, i.e., EVLM92 has been referenced, which contains the citation of the experimental data from the year of 1888 until 2004. The Korean database93 and DECHEMA94 series as well as literature data70, 76, 95–139 were referenced.…”

Section: Resultsmentioning

confidence: 99%

Transferable intermolecular potentials for carboxylic acids and their phase behavior

Vahid

Elliott

2009

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).Transferable step potentials are characterized for 39 carboxylic acids. The reference potential is treated with discontinuous molecular dynamics, including detailed molecular structure. Thermodynamic perturbation theory is used to interpret the simulation results and to provide an efficient basis for molecular modeling and characterization of the attractive forces. Four steps are used for representation of the attractive forces with only the first and last steps varied independently. The two middle steps are interpolated such that each site type is characterized by three parameters: the diameter, r, the depth of the inner well, e 1 , and the depth of the outer well, e 4 . The depths of the attractive wells are optimized to fit experimental vapor pressure and liquid density data. Generally, the vapor pressure is correlated to an overall 43% average absolute deviation (% AAD) and the liquid density to 5% AAD. The deviations tend to be largest for the higher molecular weight acids. These deviations are larger than the errors previously encountered in characterizing organic compounds, but carboxylic acids present exceptional challenges owing to their peculiar dimerization behavior. Simultaneous correlation of vapor pressure, vapor compressibility factor, and phase equilibria of water þ carboxylic acids place several constraints on the nature of the potential model, with the parameters of the present model representing a reasonable tradeoff. In other words, our model represents minimal deviations for vapor pressure, vapor compressibility factor, and phase equilibria of all acids simultaneously while varying the parameters r, e 1 , e 4 , e CC (dimerizing site bonding energy), e AD (acceptor-donor bonding energy), and K HB (hydrogen bonding volume) for the acid O¼ ¼ and OH site types. The present model is characterized by one acceptor and one dimerizing site on the carbonyl oxygen and one acceptor and one donor site on the hydroxyl oxygen. The acceptor and donor are capable of interacting with water while the dimerizing site is not. With this model, the saturated vapor compressibility factor of acids with seven or fewer carbons is near 0.5 while higher carbon ratios lead to a compressibility factor approaching 1.0. To compensate for the high vapor pressure deviations of the transferable potential model, a correction is introduced to customize the molecule-molecule self interaction energy. This adaptation results in deviations of 3.1% for vapor pressure of the pure acid database. To validate the behavior of the model for carboxylic acids in mixtures, 33 binary solutions were considered. Acids in this database ranged from formic to hexadecanoic. The average absolute deviation in bubble pressure for Additional Supporting Information may be found in the online version of this article.Correspondence concerning this article should be addressed to J. R. Elliott at dickelliott@uakron.edu aqueous acid systems is 4.4%, 10.5% for acid þ acid systems, and 4.7% for acid þ n-alkane s...

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Section: Resultsmentioning

confidence: 99%

Transferable intermolecular potentials for carboxylic acids and their phase behavior

Vahid

Elliott

2009

AIChE Journal

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show abstract

Section: Resultsmentioning

confidence: 99%

Effect of different isocyanates on the properties of soy‐based polyurethanes

Javni¹,

Zhang²,

Petrovìć³

2003

J of Applied Polymer Sci

152

127

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New types of polyurethanes were prepared by reacting soybean oil-based polyol and different isocyanates. The polyurethanes can be used as foams, elastomers, coatings, adhesives, etc. Their properties strongly depend on crosslinking density and the structure of isocyanates. Aromatic triisocyanates impart the highest density, glass transition, modulus, and tensile strength, but have the lowest elongation at break, swelling in toluene, and impact resistance. Aliphatic triisocyanates and diisocyanates give rubbery materials with the highest elongation at break, highest swelling, and the lowest tensile strength. Polyurethanes with aromatic and cycloaliphatic diisocyanates were similar in properties, with values between those of the two groups.

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