A method for preparing homogeneous-distribution
polyethylene glycol by utilizing a microchannel reactor is disclosed. The method includes (1) a step of preparing a catalytic
system, namely a step of subjecting
polyol as an initiator and an
alkali metal catalyst as a
raw material to
ultrasonic vibration dissolving; (2) a step of
raw material premixing, namely a step of feeding the catalytic systemand
epoxy ethane into a premixer at the same time, and premixing the materials at 0-10 DEG C under 0.5-1.0 MPa for 50-500 ms; (3) a micro
reaction step, namely a step of subjecting the premixed raw materials to continuous
polymerization through the microchannel reactor to obtain a reaction solution, with the
reaction temperature being controlled to be 100-200 DEG C,
residence time being 2 to 20 min, the reaction pressure being 1.0 to 4.5 MPa; and (4) a step of aftertreatment, namely a step of adding
purified water for
dissolution at 50-80 DEG C, allowing the solution to pass through an
ion exchange resin column, performing
filtration and then vacuum
dehydration, and cooling a product to
room temperature to obtain a
polyethylene glycol product. The reaction efficiency is greatly improved, which is very favorable for reducing the price of the homogeneous-distribution
polyethylene glycol. The microchannel reactor has no
scale effect and is very suitable for
industrial scale production.