Crystallisation of sodium dodecyl sulfate and the corresponding effect of 1-dodecanol addition (original) (raw)
Related papers
2018
Sodium dodecyl sulfate (SDS) exhibits crystallisation upon exposure to low temperatures, which can pose a problem in terms of product stability. In this study, non-isothermal crystallisation of SDS is investigated via differential scanning calorimetry (DSC) at concentrations that are typical of those present in many industrial liquid detergents. At different low temperatures, the crystal structures are analysed with X-ray diffraction (XRD) and it is concluded that ice formation during the surfactant crystallisation process occurs below 0 °C. The capability of the alcohol precursor, 1-dodecanol, as a seeding material for SDS crystallisation is also investigated through the use of DSC and optical microscopy. These results show that 1-dodecanol can successfully act as a seed for SDS crystallisation. Upon cooling an SDS aqueous system, the crystallisation peak in the DSC thermogram shifts to a higher temperature in the presence of 1-dodecanol. Therefore, any remnant alcohol precursor in...
A Novel Hydrate Form of Sodium Dodecyl Sulfate and Its Crystallization Process
A novel hydrate form of sodium dodecyl sulfate (SDS) was firstly discovered through a hydrate screening with the use of organic solvents, while SDS is generally prepared solely in aqueous media. Surprisingly, a novel SDS hydrate form with needle-shaped crystals produced by adding acetonitrile to a 20 wt % SDS aqueous solution at a ratio of 3:1 (v/v) and further cooling to around 5°C could be found with a trace amount in one of the two purchased SDS products that we examined. After comprehensive solid-state characterizations by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), Raman spectroscopy, dynamic vapor sorption (DVS), and elemental analysis (EA), it is also successfully made directly from the synthesis of SDS through esterification and saponification. Four times the equal proportion of acetone was added into the reaction solution at an interval of 5 min to separate the side product, sodium sulfate, from the mother liquor. The desired novel hydrate form of SDS was then obtained by cooling the filtered mother liquor to 5°C and aged for 8 h for a preferential growth.
Journal of colloid and interface science, 2018
At low temperatures stability issues arise in commercial detergent products when surfactant crystallisation occurs, a process which is not currently well-understood. An understanding of the phase transition can be obtained using a simple binary SDS (sodium dodecyl sulfate) + DDAO (N,N-dimethyldodecylamine N-oxide) aqueous system. It expected that the crystallisation temperature of an SDS system can be lowered with addition of DDAO, thus providing a route to improve detergent stability. Detergent systems are typically comprised of anionic surfactants, non-ionic surfactants and water. This study explores the crystallisation of a three component system consisting of sodium dodecyl sulfate (SDS), N,N-dimethyldodecylamine N-oxide (DDAO), and water using wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and confocal Raman microscopy. The presence of DDAO lowered the crystallisation temperature of a 20 wt% SDS system. For all aqueous mixtures of SDS + DDAO at low ...
Sodium dodecyl sulphate: A very useful surfactant for Scientific Invetigations
Journal of Knowledge-based Innovation in China
Sodium dodecylsulphate is most researched and best understood widely used anionic surfactant. It is obtained in a state of powder as well as in pellet and used in Polymer Biotechnology and Biochemistry. This review article is related to present and future uses of sodium dodecylsulphate in different applied fields. The critical micelle concentration (cmc) of Sodium dodecylsulphate changes with change in temperature and addition of electrolyte. It causes skin and eye irritation in higher concentration but such effect decreases with decrease in concentration and widely used as cleaning agent and house hold products.
2016
The densities, ultrasonic velocities and viscosities of sodium dodecyl sulphate (SDS) in water and in aqueous L-cysteine solutions have been measured as a function of SDS concentration at five equidistant temperatures ranging from 293.15 K to 313.15 K. The density data were used to calculated the apparent molar volume, v, the limiting apparent molar volume, 0 v and experimental slopes, Sv,derived from the Masson equations. The apparent molar adiabatic compressibilies, s were also calculated by using both the density and ultrasonic velocity data. The viscosity data were employed to determine the viscosity B-coefficients, and the free energies, ΔG ≠ , enthalpies, ΔH ≠ and entropies, ∆S ≠ of activation using the Nightingale and Benck, and Eyring equations. The structural properties of SDS in water and aqueous L-cysteine were studied by using
ACS Omega, 2020
Sodium dodecyl sulfate (SDS)•1/8 hydrate (NaC 12 H 25 SO 4 •1/8H 2 O) crystals were successfully produced by evaporation, antisolvent addition, cooling crystallization, and isothermal aging in a common stirred tank. A clear 33.3 wt % SDS aqueous solution was concentrated by evaporation to a 60 wt % coagel consisting of numerous SDS hydrates and water. The coagel was transformed to a clear solution when two times the volume of acetone relative to the water remaining were added. By this fluid property, a controlled crystallization was made possible in a homogeneous solution. Moreover, acetone with a water-toacetone volume ratio of 1:15 was then added as an antisolvent to induce crystallization of SDS•1/8 hydrate by cubic addition. Finally, cooling crystallization and isothermal aging were carried out to further increase the yields and gave monodispersed particle size. The stability test showed that the produced SDS•1/8 hydrate could be stored at various relative humidity environments for at least 5 days.