Modeling Mutual Solubility of n-alkanes and CO₂ Using SAFT Equation of State

Abstract

A representation of binary CO 2 /n-alkanes (n-C 3 to n-C 44 ) systems series using a SAFT equation with molecular assumptions is presented below. A minimum number of parameters were adjusted, which is eight in this case. Three parameters are required for pure CO 2 : chain length m, segment diameter σ, and interaction energy /k. Assuming that n-alkanes are made of identical segments ( /k and σ independent of carbon number n C ) but in different number, only three parameters were necessary for the whole n-alkane series (m is linearly correlated to n C ). Two additional binary interaction parameters k ij and l ij were used to model the mixtures. The van der Waals one fluid model was used with k ij and l ij independent of temperature and chain length. The agreement between calculated and measured total and partial pressures is satisfactory (within 8%) in view of the experimental accuracy and the very restrictive assumptions made. Finally, an extension to CO 2 /branched alkane binary systems is also presented.

Modeling Phase Equilibrium of H2 + n-Alkane and CO2 + n-Alkane Binary Mixtures Using a Group Contribution Statistical Association Fluid Theory Equation of State (GC−SAFT−EOS) with a kij Group Contribution Method

“…As detailed by Passarello et al, 19 in the past decades, several authors have treated such systems, using mainly cubic EOS and complex mixing rules. Their results 20,21 are comparable to (and sometimes better than) ours, i.e., with an overall average deviation within 2%-5%.…”

Synthesis of symmetrical or asymmetrical urea compounds from CO2via base catalysis

“…N,N9-di(2-heptyl)urea: GC-MS, m/z: 57 (100%), 69 (64), 100 (98), 114 (38), 167 (14), 185 (44), 256 (10); N,N9-di(2-octyl)urea: GC-MS, m/z: 57 (62%), 70 (81), 114 (100), 128 (32), 199 (43), 227 (7), 241 (7), 255 (5), 284 (11); N,N9-dibutylurea: GC-MS, m/z: 57 (100%), 74 (53), 87 (29), 101 (45), 115 (4), 129 (22), 143 (13), 157 (11), 172 (45); N,N9-dihexylurea: GC-MS, m/z: 57 (100%), 85 (45), 99 (56), 115 (36), 128 (36), 143 (12), 158 (23), 185 (58), 199 (39), 228 (31); N,N9-diheptylurea: GC-MS, m/z: 57 (100%), 86 (25), 101 (34), 116 (53%), 142 (45), 185 (10), 199 (59), 213 (49), 227 (19), 241 (6), 256 (38); N,N9-dioctylurea: GC-MS, m/z: 57 (100%), 69 (54), 85 (26), 99 (71), 112 (33), 130 (56), 157 (28), 171 (14), 185 (14), 199 (8), 213 (40), 227 (35), 241 (19), 255 (16), 269 (5), 284 (24); N,N9-dibenzylurea: GC-MS, m/z: 79 (21%), 91 (54), 106 (100), 149 (17); 240 (21); N,N9-di(t-butyl)urea: GC-MS, m/z: 58 (100%), 157 (8), 172 (3); N-Butyl-N9-methylbutylurea: GC-MS, m/z: 57 (100%), 72 (13), 88 (15), 101 (9), 114 (37), 143 (22), 157 (2), 186 (19);…”

“…N-Hexyl-N9-methylbutylurea: GC-MS, m/z: 57 (100%), 70 (9), 88 (32), 99 (19), 114 (64), 128 (14), 143 (5), 157 (5), 171 (17), 185 (5), 214 (26); N-2-heptyl-N9-methylbutylurea: GC-MS, m/z: 57 (67%), 70 (25), 84 (15), 98 (15), 114 (70), 140 (100), 157 (29), 168 (13), 228 (3); N-Octyl-N9-methylbutylurea: GC-MS, m/z: 57 (100%), 88 (30), 99 (30), 114 (57), 128 (11), 156 (12), 171 (5), 199 (7), 242 (11).…”

“…However, similar mole fractions are found in literature data for binary mixtures of CO 2 and acetonitrile or decane. 19 It seems that differences in molar CO 2 reactor content at the cold start of the reaction are minor. Higher temperatures decrease the CO 2 concentration in solution, but these decreases are expected to be parallel for all solvents.…”

“…The equilibrium can be attained more quickly by adding cocatalytic compounds. A series of ammonium salts and some bases, such as 4-dimethylaminopyridine (DMAP) or PPh 3 were tested in the urea formation from 2-heptylamine (Table 3, entries [14][15][16][17][18][19]. Particularly quaternary ammonium compounds give good results.…”