Elsevier

Fluid Phase Equilibria

Volume 332, 25 October 2012, Pages 144-150
Fluid Phase Equilibria

Solubility of triclosan and iodopropynyl butylcarbamate in pure alkanols at several temperatures

https://doi.org/10.1016/j.fluid.2012.05.020Get rights and content

Abstract

Solubility data for triclosan and iodopropynyl butylcarbamate (IPBC) in ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol were measured. Solid–liquid phase equilibrium measurements were conducted at several temperatures (from 278.15 to 318.15 K). After drying the equilibrium saturated solutions, gravimetric measurement was used to determine experimental solubility. The data were correlated using a equation for the solubility of a solid in a liquid and the nonrandom two liquid (NRTL), universal quasi-chemical (UNIQUAC) and Wilson models for activity coefficients. The data are well fitted with all three models for the six pure alcohols studied here.

Highlights

► Solubility data of triclosan and iodopropynyl butylcarbamate in pure alkanols were measured. ► The experimental data were correlated with NRTL, UNIQUAC and Wilson models. ► The data are fit well with all three models for the six pure alcohols studied. ► Adjustable interaction parameters were suggested.

Introduction

Triclosan (2,4,4′-trichloro-2′-hydroxydiphenyl ether, Chemical Abstract Service Registry Number 3380-34-5) is an antibacterial and antifungal agent. This bactericide has been in daily use for more than 30 years in many households and personal and health care products. It is the primary or secondary active agent (as a stabilizing agent) in a multitude of liquid detergents, plastic kitchenware, liquid hand soaps (used in both homes and in hospitals), deodorants, cosmetics, creams, lotions, mouthwash, toothpaste, carpets, and toys [1]. Triclosan inhibits bacterial growth by blocking lipid biosynthesis [2]. Iodopropynyl butylcarbamate (IPBC, Chemical Abstract Service Registry Number 55406-53-6) is a halogenated unsaturated carbamate and a member of the carbamate family of insecticides. IPBC is a water-based preservative agent originally used in the wood and paint industries [3], [4]. However, IPBC is currently used in significant widespread cosmetic and pharmaceutical applications such as an antidandruff agent [5], [6] and fungicide [7]. IPBC is active against Malassezia and yeasts that cause some skin disorders (pruritis and dermatitis).

Solid–liquid phase equilibrium (SLE) data are very crucial data in many chemical engineering processes such as extraction, purification. During these processes, super-saturation, that is, the difference between the saturation solubility and the real concentration, is the source of power for nucleation, growth and agglomeration phenomena that affect the crystal size distribution, morphology, filterability and polymorphic distribution of the product. Accordingly, solubility data in different solvents are fundamental data for designing a crystallization process. Triclosan and IPBC can be purified by crystallization using several solvents and obviously crystallization depends on the solubility. Therefore, solubility data in different solvents are very critical in industrial applications including purification. However, limited data are available on the solubility of triclosan and IPBC in solvents [8].

The concentration of a saturated solution of solute dissolved in solvent has been measured using a laser technique [9], [10], an instrumental analytical method [11] and a gravimetric method [12]. The laser technique can be employed to obtain data quickly, but it is difficult to check whether the solid–liquid equilibrium is reached, particularly for systems that can emulsify. The instrumental analytical method is used to determine the concentration of a saturated solution by chemical methods of analysis such as high performance liquid chromatography (HPLC) or the ultraviolet (UV) method and is useful to measure systems in which solubility is very low. The gravimetric method is simple and reliable but is usually used to measure systems in which the solubility is high. The solubility of triclosan and IPBC in different alcohols is too high to be measured by the analytical method; thus, the gravimetric method was selected for this study.

The solubilities of triclosan and IPBC were measured in six alkanols (ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol) at several temperatures (from 278.15 to 318.15 K) using gravimetric measurements after drying the equilibrium saturated solutions. The data were correlated with the nonrandom two liquid (NRTL) [13], universal quasi-chemical (UNIQUAC) [14], and Wilson [15] models for activity coefficients.

Section snippets

Materials

Ethanol (min. 99.9%), 1-propanol (min. 99.9%), 1-butanol (min. 99.7%), 1-pentanol (min. 99.0%), 1-hexanol (min. 99.0%), dl-alanine (min. 99.0%) were supplied by Sigma–Aldrich (St. Louis, MO, USA). 1-Heptanol (min. 98.0%) was purchased from Tokyo Chemical Industry (Tokyo, Japan). Triclosan (min. 99.0%) and IPBC (min. 99.0%) were supplied by KCI Ltd. Co. (Seoul, South Korea) and SPC Co. (Seoul, South Korea), respectively. Water was passed through an ion exchanger and distilled. All chemicals were

Results and discussion

The solubility of triclosan and IPBC was very high in the selected pure alcohols; thus, the gravimetric method was chosen for this research. The solubility of dl-alanine in water was measured at several temperatures (from 278.15 to 328.15 K) to check the reliability of the solid–liquid equilibrium measurement apparatus. Fig. 1 and Table 1 show the results compared to literature obtained by Daton and Schmidt [17] for each temperature. The dl-alanine solubility data were in good agreement with the

Conclusions

SLE data for triclosan and IPBC in ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol were measured at several temperatures (from 278.15 to 318.15 K). Gravimetric measurements were used to determine the experimental solubility after drying the equilibrium solutions. The experimental solubility values of triclosan and IPBC in pure alcohols increased with an increase of temperature and with a decrease of chain length of selected alkanols. The activity coefficient for solubility

Acknowledgments

This study was supported by the Brain Korea 21 Program supported by the Ministry of Education, Science, and Technology (MEST) and by the National Research Foundation of Korea (NRFK) grant funded by the Korea government (MEST) (No. 2009-0078957).

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