E.i. Dupont De Nemours and Company

Albert M Stock

James D Verbsky

Wilson S Tse

In the refining of crude acidic tetrahydrofuran prepared from acetylene and formaldehyde, corrosion of refining equipment and formation of color-producing methacrolein can be minimized by bringing the pH value of the crude tetrahydrofuran to within the range 5-11 before the refining step.

Refining tetrahydrofuran

In the ethynylation of formaldehyde in the presence of a copper acetylide catalyst to produce butynediol, pH is controlled by the incremental or continuous addition of an alkali metal hydroxide and an alkali metal carbonate at an equivalent ratio of hydroxide ion to carbonate ion of 1:1-4:1.

Process for the control of pH in the ethynylation of formaldehyde

When acetylene flow to the continuous, aqueous ethynylation reaction of formaldehyde and acetylene, using a copper acetylide complex as the catalyst, is interrupted, resulting cuprene formation can be inhibited by maintaining the reaction mass at a pH of 3.5-5 until normal acetylene flow is resumed.

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LaPorte, TX, United States of America

Albert M Stock