| 摘要 |
PURPOSE:To produce a novolak phenolic resin extremely low in a content of free phenols and closed oxidation products, by effecting the reaction under a specified condition including the use of an innert gas and a high vacuum. CONSTITUTION:A phenol (e.g., phenol) is condensed with an aldehyde (e.g., formalin) in the presence of an acid catalyst (e.g., hydrochloric acid), dehydrated and removed from the phenol. In the above operations, while the oxygen concentration in the reactor is kept at above 1% or below by using an inert gas (e.g., nitrogen of a purity >=about 99.9%), the condensation reaction is effected at about 95-105 deg.C for about 1-3hr, the reaction mixture is dehydrated by blowing and bubbling a heated inert gas (80-150 deg.C) at a rate of about 0.1-1Nm<3>/hr/kg. reaction solution, and the reaction mixture is separated from free phenol by blowing a heated inert gas in a vacuum <=120Torr, provided that the entire reaction and the operations are performed at 150 deg.C or below.
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