Preparation and recovery of ethers

The method which comprises

• distilling a reaction mixture containing methanol and methyl t-butyl ether in a first distilling operation thereby forming first azeotrope overhead containing methanol and methyl t-butyl ether and first azeotrope bottoms containing methanol;
• distilling said first azeotrope overhead containing methanol and methyl t-butyl ether in a second distillation operation in the presence of n-pentane thereby forming second azeotrope overhead containing methanol and n-pentane and secnd azeotrope bottoms containing desired product methyl t-butyl ether;
• rectifying at least a portion of said first azeotrope bottoms containing methanol and at least a portion of said aqueous extract containing water and methanol thereby forming a rectification overhead containing methanol;
• recovering said rectification overhead containing methanol;
• withdrawing said second azeotrope bottoms containing desired product methyl t-butyl ether;
• contacting said second azeotrope overhead containing methanol and n-pentane in a contacting operation with water thereby forming aqueous extract containing water and methanol and raffinate containing n-pentane;
• fractionating said raffinate thereby forming fractionation overhead containing n-pentane and fractionation bottoms containing water;
• and
• passing at least a portion of said fractionation overhead containing n-pentane to said second distillation operation.

The method which comprises

• reacting methanol and isobutene in the presence of a solid resin etherification catalyst thereby forming a reaction mixture including unreacted methanol, unreacted isobutylene, and product methyl t-butyl ether;
• separating said unreacted isobutene from said reaction mixture thereby forming a separated reaction mixture containing unreacted methanol and product methyl t-butyl ether;
• distilling said separated reaction mixture containing methanol and methyl t-butyl ether in a first distilling operation thereby forming first azeotrope overhead containing methanol and methyl t-butyl ether and first azeotrope bottoms containing methanol;
• distilling said first azeotrope overhead containing methanol and methyl t-butyl ether in a second distillation operation in the presence of n-pentane thereby forming second azeotrope overhead containing methanol and n-pentane and second azeotrope bottoms containing desired product methyl t-butyl ether;
• withdrawing said second azeotrope bottoms containing desired product methyl t-butyl ether;
• contacting said second azeotrope overhead containing methanol and n-pentane in a contacting operation with water thereby forming aqueous extract containing water and methanol and raffinate containing n-pentane;
• fractionating said raffinate thereby forming fractionation overhead containing n-pentane and fractionation bottoms containing water.

The method which comprises

• reacting methanol and isobutene in the presence of a solid resin etherification catalyst thereby forming a reaction mixture including unreacted methanol, unreacted isobutylene, and product methyl t-butyl ether;
• separating said unreacted isobutene from said reaction mixture thereby forming a separated reaction mixture containing 20 - 50% of unreacted methanol and 40% - 70 % of product methyl t-butyl ether;
• distilling said separated reaction mixture in a first distilling operation thereby forming first azeotrope overhead containing 13 - 17 % of methanol and 83 % - 87 % of methyl t-butyl ether and first azeotrope bottoms containing methanol;
• distilling said first azeotrope overhead containing methanol and methyl t-butyl ether in a second distillation operation in the presence of 10 - 11 parts of n-pentane per part of methanol thereby forming second azeotrope overhead containing 8% - 10% of methanol and 90- 92% of n-pentane and second azeotrope bottoms consisting essentially of desired product methyl t-butyl ether;
• withdrawing said second azeotrope bottoms containing desired product methyl t-butyl ether;
• contacting said second azeotrope overhead containing methanol and n-pentane in a contacting operation with 3 - 4 parts of water per part of methanol thereby forming aqueous extract containing water and methanol and raffinate containing n-pentane;
• fractionating said raffinate thereby forming fractionation overhead containing n-pentane and fractionation bottoms containing water;
• passing at least a portion of said fractionation overhead containing n-pentane to said second distillation operation;
• rectifying at least a portion of said first azeotrope bottoms containing methanol and at least a portion of said aqueous extract containing water and methanol thereby forming a rectification overhead containing methanol;
• and
• passing at least a portion of said rectification overhead containing methanol to said reaction operation.