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

16033

Sigma-Aldrich

1,2-Propanediol, meets analytical specification of Ph. Eur., BP, USP, ≥99.5%

E2385

Supelco

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

45983

Supelco

Acetonitrile, analytical standard

02851

Sigma-Aldrich

Ethanol, for residue analysis

29221

Sigma-Aldrich

Ethanol, tested according to Ph. Eur.

82280

Sigma-Aldrich

1,2-Propanediol, puriss. p.a., ACS reagent, ≥99.5% (GC)

02891

Sigma-Aldrich

Ethanol, purum, secunda spirit, denaturated with 2% 2-butanone, S15, ~96% (based on denaturant-free substance)

82281

Sigma-Aldrich

1,2-Propanediol, tested according to Ph. Eur.

P50404

Sigma-Aldrich

1,3-Propanediol, 98%

W217816

Sigma-Aldrich

Butyl alcohol, natural, ≥99.5%, FCC, FG

493538

Sigma-Aldrich

Ethyl alcohol, Pure, 190 proof, meets USP testing specifications

493511

Sigma-Aldrich

Ethyl alcohol, Pure, 190 proof, ACS spectrophotometric grade, 95.0%

12279

Supelco

1,2-Propanediol, analytical standard

271004

Sigma-Aldrich

Acetonitrile, anhydrous, 99.8%

134368

Sigma-Aldrich

1,2-Propanediol, ReagentPlus^®, 99%

459836

Sigma-Aldrich

Ethyl alcohol, Pure, 200 proof, anhydrous, ≥99.5%

398039

Sigma-Aldrich

1,2-Propanediol, ACS reagent, ≥99.5%

1601340

USP

Residual Solvent Class 2 - Acetonitrile, United States Pharmacopeia (USP) Reference Standard

792780

Sigma-Aldrich

Ethyl alcohol, Pure, 200 proof, ACS reagent, meets USP testing specifications, Excise Tax-free, Permit for use required

792799

Sigma-Aldrich

Ethyl alcohol, Pure, 190 proof, ACS reagent, meets USP testing specifications, Excise Tax-free, Permit for use required

110086

Sigma-Aldrich

Acetonitrile, ReagentPlus^®, 99%

51976

Sigma-Aldrich

Ethanol, BioUltra, for molecular biology, ≥99.8%, (absolute alcohol, without additive, A15 o¹)

02890

Sigma-Aldrich

Ethanol, purum, fine spirit, denaturated with 2% 2-butanone, F25 MEK¹, ~96% (based on denaturant-free substance)

02856

Sigma-Aldrich

Ethanol, purum, absolute ethanol, denaturated with 4.8% isopropanol, A15 IPA¹, ≥99.8% (based on denaturant-free substance)

02857

Sigma-Aldrich

Ethanol, purum, fine spirit, denaturated with 4.8% methanol, F25 METHYL¹, ~96% (based on denaturant-free substance)

459844

Sigma-Aldrich

Ethyl alcohol, Pure, 200 proof, ACS reagent, ≥99.5%

493546

Sigma-Aldrich

Ethyl alcohol, Pure, 200 proof, meets USP testing specifications

494445

Sigma-Aldrich

Acetonitrile, biotech. grade, ≥99.93%

60004

Sigma-Aldrich

Acetonitrile, ≥99.5% (GC)

E7023

Sigma-Aldrich

Ethyl alcohol, Pure 200 proof, for molecular biology