Processes are described for isomerizing one or more C14-C24 alpha olefins to produce an isomerization mixture comprising one or more C14-C24 internal olefins comprising contacting an olefinic feed comprising the one or more C14-C24 alpha olefins with a catalyst under isomerization conditions, wherein the catalyst comprises a microporous crystalline aluminosilicate having an MWW framework. The resulting isomerization mixture typically exhibits a low pour point with maintained biodegradability properties as compared to the olefinic feed, and is particularly useful in drilling fluid and paper sizing compositions.