Polyalkylene glycol derivative and process for producing same

A process for producing a polyalkylene glycol derivative of the formula (X):

• R—(OA)nOH (X)
• wherein R represents a hydrocarbon group having 1 to 7 carbon atoms, a protective group of a hydroxyl group, a protective group of an amino group, a protective group of an aldehyde group, a protective group of a carboxyl group or a protective group of a mercapto group;
• OA is an oxyalkylene group having 2 to 4 carbon atoms;
• and n is an average number of moles of the oxyalkylene group added and is 600 to 2000,
• the process comprising the following steps (A), (B), (C) and (D):
• Step (A):
• a step of adding 5 to 50% by mol of an alkali catalyst to a compound represented by the formula (Y):
• R—OH (Y)
• wherein R represents a hydrocarbon group having 1 to 7 carbon atoms, a protective group of a hydroxyl group, a protective group of an amino group, a protective group of an aldehyde group, a protective group of a carboxyl group or a protective group of a mercapto group,
• Step (B):
• a step of reacting an alkylene oxide having 2 to 4 carbon atoms under a condition of 50 to 130° C. until an average number of moles of the oxyalkylene group OA added reaches a range of 5 to 500 to obtain a polyalkylene glycol derivative,
• Step (C):
• a step of adding 10 to 5000% by mass of a hydrocarbon solvent to the polyalkylene glycol derivative of the step (B) to dilute it and removing remaining water by azeotropy, and
• Step (D):
• a step of reacting an alkylene oxide having 2 to 4 carbon atoms with the polyalkylene glycol derivative of the step (B) under a condition of 50 to 130° C. until an average number of moles of the oxyalkylene group OA added reaches a range of 600 to 2000.