Separation of ethanol from t-butanol by extractive distillation
OwnerLloyd Berg, Mark G. Vosburghinventors
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Abstract
Ethanol and t-butanol cannot be separated from each other by distillation because of the proximity of their boiling points. Ethanol can be readily separated from t-butanol by using extractive distillation in which the extractive agent is a higher boiling oxygenated organic compound or a mixture of two or more of these. Typical examples of effective agents are: methyl benzoate; benzyl benzoate and benzoic acid; methyl salicylate, hexahydrophthalic anhydride and salicylic acid.
Claims11
A method for recovering ethanol from a mixture of ethanol and tertiary butanol which comprises distilling a mixture of ethanol and t-butanol in a rectification column in the presence of about one to two parts of extractive agent per part of ehtanol - t-butanol mixture, recovering ethanol as overhead product and obtaining the extractive agent and t-butanol from the stillpot, the extractive agent comprises at least a benzoate containing from seven to twenty-six carbon atoms.
A method for recovering ethanol from a mixture of ethanol and t-butanol which comprises distilling a mixture of ethanol and t-butanol in a rectification column in the presence of about one to two parts of extractive agent per part of ethanol t-butanol mixture, recovering ethanol as overhead product and obtaining the extractive agent and t-butanol from the stillpot, the extractive agent comprises a benzoate containing from seven to twenty-six carbon atoms and at least one material from the group consisting of benzoic acid, cinnamic acid, salicylic acid, phthalic anydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride and trimellitic anhydride.
A method for recovering ethanol from a mixture of ethanol and t-butanol which comprises distilling a mixture of ethanol and t-butanol in a rectification column in the presence of about one to two parts of extractive agent per part of ethanol- t-butanol mixture, recovering ethanol as overhead product and obtaining the extractive agent and t-butanol from the stillpot, the extractive agent comprises a hydrogenated phthalic anhydride containing from eight to nine carbon atoms.
Dependencies are inferred from the claim text.