Solubility and thermodynamic function of vanillin in ten different environmentally benign solvents.

Solubility and thermodynamic function of vanillin in ten different environmentally benign solvents.

Food chemistry (2015-03-15)

Faiyaz Shakeel, Nazrul Haq, Nasir A Siddiqui

ABSTRACT

The solubility of vanillin in ten different environmentally benign solvents namely water, ethanol, ethylene glycol (EG), ethyl acetate (EA), isopropanol (IPA), propylene glycol (PG), polyethylene glycol-400 (PEG-400), Transcutol, butanol-1 and butanol-2 was measured and correlated at T=(298-318)K. The resulting experimental data were correlated with the modified Apelblat and Van't Hoff models. Both the models showed good correlation of experimental solubility data with calculated ones with root mean square deviations in the range of (0.08-1.55)%. The mole fraction solubility of vanillin was observed highest in PEG-400 (4.29 × 10(-1) at 298 K) followed by Transcutol, EA, butanol-2, ethanol, EG, PG, IPA, butanol-1 and water from T=(298-318)K. The results of thermodynamic function in terms of dissolution enthalpy, Gibbs energy and dissolution entropy showed endothermic, spontaneous and entropy-driven dissolution of vanillin in all environmentally benign solvents.

MATERIALS

Product Number

Brand

Product Description

650501

Sigma-Aldrich

Acetone, HPLC Plus, for HPLC, GC, and residue analysis, ≥99.9%

V1104

Sigma-Aldrich

Vanillin, ReagentPlus^®, 99%

P4347

Sigma-Aldrich

Propylene Glycol, meets USP testing specifications

B7906

Sigma-Aldrich

1-Butanol, for molecular biology, ≥99%

PHR1070

Supelco

Dehydrated Alcohol, Pharmaceutical Secondary Standard; Certified Reference Material

PHR1219

Supelco

Acetone, Pharmaceutical Secondary Standard; Certified Reference Material

PHR1051

Supelco

Propylene glycol, Pharmaceutical Secondary Standard; Certified Reference Material

PHR1091

Supelco

Vanillin melting point standard, Pharmaceutical Secondary Standard; Certified Reference Material

77634

Supelco

Mettler-Toledo Calibration substance ME 51143093, Vanillin, traceable to primary standards (LGC)

679186

Sigma-Aldrich

Acetonitrile solution, contains 0.05 % (w/v) ammonium formate, 5 % (v/v) water, 0.1 % (v/v) formic acid, suitable for HPLC

1006801

USP

Acetone, United States Pharmacopeia (USP) Reference Standard

V0050000

Vanillin, European Pharmacopoeia (EP) Reference Standard

PHR1209

Supelco

1-Butanol, Pharmaceutical Secondary Standard; Certified Reference Material

1576708

USP

Propylene glycol, United States Pharmacopeia (USP) Reference Standard

Y0001547

Propylene glycol, European Pharmacopoeia (EP) Reference Standard

PHR1563

Supelco

2-Butanol, Pharmaceutical Secondary Standard; Certified Reference Material

PHR1245

Supelco

Vanillin, Pharmaceutical Secondary Standard; Certified Reference Material

179124

Sigma-Aldrich

Acetone, ACS reagent, ≥99.5%

B85919

Sigma-Aldrich

2-Butanol, ReagentPlus^®, ≥99%

32201

Sigma-Aldrich

Acetone, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.5% (GC)

320110

Sigma-Aldrich

Acetone, ACS reagent, ≥99.5%

24201

Sigma-Aldrich

Acetone, puriss., meets analytical specification of Ph. Eur., BP, NF, ≥99% (GC)

30304

Supelco

Vanillin, certified reference material, TraceCERT^®, Manufactured by: Sigma-Aldrich Production GmbH, Switzerland

534064

Sigma-Aldrich

Acetone, histological grade, ≥99.5%

PHR1320

Supelco

Residual Solvent - Acetonitrile, Pharmaceutical Secondary Standard; Certified Reference Material

34850

Sigma-Aldrich

Acetone, suitable for HPLC, ≥99.8%

34867

Sigma-Aldrich

1-Butanol, suitable for HPLC, ≥99.7%

1012772

USP

Dehydrated Alcohol, United States Pharmacopeia (USP) Reference Standard

32221

Sigma-Aldrich

Ethanol, puriss. p.a., absolute, ≥99.8% (GC)

E2385

Supelco

Ethanol standards 10% (v/v), 10 % (v/v) in H₂O, analytical standard