| 摘要 |
The process relates to a method of improving the color and/or reducing the oxidized acids content of the disproportionated product obtained by heating rosin acids in rosin and tall oil with a catalyst comprising iodine, an iron compound and ammonia, an ammonium salt or an amine. The improvement comprises a pretreatment step in which the starting material is heated with an effective amount not in excess of 0.5% by weight of elemental sulphur, based on the weight of starting material for a period, usually less than one hour. As little as 0.1% by weight of sulphur is sufficient in most cases.
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