ABSTRACT

A novel co-crystal of trans-(R,R)-1,2-cyclohexanediol and (R,R)-tartaric acid (with 1:1 molar ratio) (1) has been found to be a key crystalline compound in the resolution of (+-)- trans-1,2-cyclohexanediol by supercritical fluid extraction. The molecular and crystal structure of this co-crystal, which crystallizes in orthorhombic crystal system (space group P212121, a = 6.7033(13) A, b = 7.2643(16), c=24.863(5), Z=4), has been solved by single crystal X-ray diffraction (R = 0.064). The packing arrangement consists of two dimensional layers of sandwich-like sheets, where the inner part is constructed by double layers of tartaric acids which hydrophilicity is covered on both upper and bottom side by cyclohexanediols with the hydrophobic cyclohexane rings pointing outward. Thus, a rather complex hydrogen bonding pattern is constructed. The relatively high melting point (133deg C) observed by both simultaneous TG/DTA and DSC, the main features of FTIR-spectrum, and also the low solubility of 1 in non-protic solvents are explained by the increased stability of this crystal structure. DSC studies on binary mixtures of cocrystal 1 with (R,R)-1,2-cyclohexanediol or (R,R)-tartaric acid, revealed eutectic temperatures of Teu=100 or 131deg C, respectively. Between (S,S)-1,2-cyclohexanediol and (R,R)-tartaric acid a eutectic temperature of Teu= 86deg C have also been observed. The phase relations have been confirmed by powder X-ray diffraction, as well.

Compounds

#	Formula	Name
1	C4H6O6	(2R,3R)-2,3-dihydroxybutanedioic acid
2	C6H12O2	(1R,2R)-1,2-cyclohexanediol
3	C6H12O2	1,2-cyclohexanediol, (1S,2S)-
4	C6H12O2	trans-1,2-cyclohexanediol
5	C10H18O8	(R,R)-tartaric acid (R,R)-1,2-cyclohexanediol co-crystal (1:1)

Datasets

The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type	Compound-#	Property	Variable	Phase	Method	#Points
POMD	1	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	1	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	2	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	2	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	3	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	3	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	4	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	4	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	5	Mass density, kg/m3 ; Crystal	Temperature, K; Crystal Pressure, kPa; Crystal	Crystal	X-ray diffraction	1
POMD	5	Normal melting temperature, K ; Crystal		Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	5	Molar enthalpy of transition or fusion, kJ/mol ; Crystal		Crystal Liquid Air at 1 atmosphere	DSC	1

Thermodynamics Research Center / ThermoML | Thermochimica Acta

A Novel Co-crystal of (R,R)-1,2-Cyclohexanediol with (R,R)-Tartaric Acid, a Key Structure for Resolution of the Racemic (+-)-trans-Diol in Supercritical Carbon Dioxide, and the Binary Melting Phase Relations.

Thorey, P.[Paul], Bombicz, P.[Petra], Szilagyi, I. M.[Imre Miklos], Molnar, P.[Peter], Bansaghi, G.[Gyorgy], Szekely, E.[Edit], Simandi, B.[Bela], Laszlo, P.[Parkanyi], Pokol, G.[Gyorgy], Madarasz, J.[Janos]

ABSTRACT