Process Improvement Using Solubility Characteristics

A process having an operating temperature range, Tmin to Tmax, at which solubility of a non-electrolyte solute in a solvent is maximized, the process comprising:

• forming a mixture comprising the non-electrolyte solute and the solvent, wherein the solubility of the solute in the solvent is less than the ideal solubility at temperature, T, the temperature of the mixture being between Tmin and Tmax;
• wherein
• γsolute is the activity coefficient of the solute in a two component mixture of the solute in the solvent at a temperature, T, derived from equation (5);
• ln
• 
• 
• γ
• solute
• 
• x
• solute
• =
• -
• Δ
• 
• 
• H
• solute
• F
• R
• 
• (
• 1
• T
• -
• 1
• T
• m
• 
• (
• solute
• )
• )
• (
• 5
• )
• γsolute is the mole fraction of dissolved solute in a saturated two component mixture of solute and solvent at a temperature, T, in K;
• R is the ideal gas constant in cal/K·mol;
• −ΔHFsolute is the heat of fusion in cal/g·mol of the solute;
• Tm(solute) is the absolute melting temperature of the solute, in K;
• Tmin is a temperature, in K, where an absolute value of γsolute is greater than one and less than about 10 and the second derivative of a function of γsolute with respect to temperature becomes a positive value;
• and
• Tmax is a temperature, in K, which is greater than Tmin and less than (Tmin+0.8(Tm(solute)−Tmin)).

A process having an operating temperature range, Tmin to Tmax, at which solubility of a non-electrolyte solute in a solvent is maximized, the process comprising forming a mixture comprising the non-electrolyte solute and the solvent, wherein the solubility of the solute in the solvent is less than the ideal solubility at a temperature, T, the temperature of the mixture being between Tmin and Tmax;

• wherein
• xsolute is the mole fraction of dissolved solute in a saturated two component mixture of solute and solvent at a temperature, T;
• Tm(solute) is the normal melting temperature of the solute;
• Tmin is a temperature where the second derivative of a function of xsolute with respect to temperature becomes a negative value;
• and
• Tmax is a temperature greater than Tmin and less than (Tmin+0.8(Tm(solute)−Tmin)).

A process having an operating temperature range, Tmin to Tmax, at which solubility of a non-electrolyte solute in a solvent is maximized, the process comprising forming a mixture comprising the non-electrolyte solute and the solvent, wherein the solubility of the solute in the solvent is less than the ideal solubility at a temperature, T, the temperature of the mixture being between Tmin and Tmax;

• wherein
• wt. %solute is the wt. % of dissolved solute in a saturated two component mixture of solute and solvent at a temperature, T;
• Tm(solute) is the normal melting temperature of the solute;
• Tmin is a temperature where the second derivative of a function of wt. %solute with respect to temperature changes becomes a negative value;
• and
• Tmax is a temperature greater than Tmin and less than about (Tmin+0.8(Tm(solute)−Tmin)).

A process for separating a mixture of an alcohol, an ether and water, the process comprising:

• introducing an aqueous mixture of an alcohol and an ether into a distillation column;
• separating the mixture to produce water and a vapor comprising the ether and the alcohol;
• introducing the vapor exiting an upper portion of the column into a lower portion of a knockback condenser;
• and
• condensing the vapor in the knockback condenser to form an ether-rich vapor exiting an upper portion of the knockback condenser and an alcohol-rich liquid exiting the lower portion of the knockback condenser, wherein the ether-rich vapor contains at least about 50 wt. % of the ether in the mixture.