Glycerol solubility parameter

It is shown that the solubility of fullerenes in vegetable oils can be predicted and justified on the basis of the solubility parameters of C60 and C70 and of the glycerol esters of fatty acids. A detailed procedure for the calculation of the solubility parameters of fullerenes and vegetable oils by group increment is reported. 

Keywords Adducts, C60, C70, esters of fatty acid, excipients, fatty acids, fullerenes, glycerol esters of fatty acids, grafting, group increment method, solubility, solubility parameter, vehicles for drug delivery, vegetable oils, triglycerides... 

The Solubility Parameter of Fatty Acids and Fatty Acids Esters of Glycerol... 

Being a mixture of different fatty acids esters of glycerol, the calculation with group increment of the solubility parameter of vegetable oils presents some... 

The calculated solubility parameter derived from the Van Krevelen approach has been compared with the experimental solubility parameters of C60 and C70 reported in the literature and derived experimentally. An excellent agreement has been found between the calculated and the experimental <5d values. A comparison with the calculated solubility parameter of the vegetable oils, under certain conditions, permits to show that a good solubility of fullerenes in glycerol esters of fatty acids can be expected. Fulleiene solubility in molten free fatty acids can be predicted on the basis of solubility parameters comparison and it has been verified by dissolving C60 and C70 in molten fatty acids. 

Silicone fluids are soluble in aliphatic, aromatic and chlorinated hydrocarbons as is to be expected from their low solubility parameter. They are insoluble in liquids of higher solubility parameter such as acetone, ethanol, glycerol and water. The fluids are resistant to many inorganic reagents but are attacked by strong acids and alkalis. 

To assess the accuracy of the simulations and the COMPASS force field in these calculations, two organic solvents were studied first. Glycerol was chosen because it is a polyol, in common with the building blocks of cellulose 2-methanol-tetrahydro-pyran (THPMeOH) was chosen because its ring structure is analogous to the repeat unit of cellulose. The calculated densities and solubility parameters are presented in Table 4.1 along with the experimental values. 

The solubility of alkylene oxides in the reaction mass is another important parameter, because the reaction takes place in the liquid phase and the gaseous monomer is transferred from the gas phase to the liquid phase. Because all the propoxylation and ethoxylation reactions are strongly diffusion dependent, the surface of the gas-liquid interface is a very important parameter for the mass transfer from the gas to liquid, and the real consumption of alkylene oxides depends strongly on this parameter. Between the alkoxylation of fatty alcohols and the alkoxylation of glycerol, there are many similarities if we use the Santacesaria kinetic model. Thus if RXH are considered to be the hydroxyl groups of the starter, the reaction rate of alkylene oxides addition is ... 

The Crismer value (CV) measures the miscibility of an oil in a standard solvent mixture, composed of /-amyl alcohol, ethyl alcohol, and water in volume proportion 5 5 0.27 (Table 4.13). This parameter was a specification criterion used for international trade, mostly in Europe. However, it is rarely used today. Values are generally characteristic, within a narrow limit, for each kind of oil. The miscibility of oil is related to the solubility of the glycerol esters and is affected mainly by the unsaturation and chain length of the constituent fatty acids. 

Physical Parameters. It is a slightly bitter, ciystalline scales or powder. 1 g dissolves in 1300 ml cold water, 82 ml boiling water, 15 ml cold ethanol, 2.8 ml boiling ethanol, 14 ml chloroform, 90 ml ether, and soluble in glycerol. It gives a pasty mass with a salicylic acid, iodine, spirit nitrous ether, chloral hydrate, and phenol. 

Physical Parameters. It is obtained as a liquid, but forms laminar crystals at low temperature having mp 20.5°C. It has physical parameters as d l 1.033 bp 202°C and n 1.533 g. Its flash point when determined by closed cup method is found to be 105°C. It is slightly soluble in water and freely soluble in alcohol, chloroform, glycerol, fatty oils and ether. Its solution in concentrated HgSO gives a distinct orange colouration. 

Physical Parameters. Guaifensin is obtained as minute rhombic prisms from ether, mp 78.5-79°C and bpjg 215°C. It has a slight bitter aromatic taste. 1 g dissolves in 20 ml water at 25°C much more soluble in hot water freely soluble in ethanol soluble in chloroform, glycerol, propylene glycol, DMF moderately soluble in benzene and almost insoluble in petroleum ether. 

Physical Parameters. It is normally obtained as a practically tasteless crystals obtained from methanol, mp 105-106°C. It is formd to be very sparingly soluble in hot water (0.05%), somewhat more (1 to 2%) in [95% (v/v)] ethanol and also soluble in glycerol and in propylene glycol. 

Solution ProportiGS. The amide group (—CONH2) in poly(acrylamide) provides for its solubility in water and in a few other polar solvents such as glycerol, ethylene glycol, and formamide. We can acquire a sense of poly(acrylamide) s affinity for water by examining a few characteristic parameters. Theta ( ) conditions for a polymer delineate a particular combination of solvent and temperature at which the polymer acts in an ideal manner (22), ie, the chains behave as random coils. The 0 temperature of poly(acrylamide) in water has been determined to be -8°C (23). Thus, water at 25°C is a solvent of intermediate quality for poly(acrylamide). Aqueous methanol (40 vol%), however, is a solvent for poly(acrylamide) at 25°C (24). The Flory / parameter, which is a measure of the relative affinity between the polymer segments with each other vs with the solvent, is 0.5 under conditions. The Flory / parameter of poly(acrylamide) has been determined to be 0.48 in water at 30°C (25). These and other properties of poly(acrylamide) in solution are collected in Table 2. 

---