** Chemical maker Synthomer worst performing UKmidcap after co cuts profit outlook.
** Blames lower demand from construction markets in Europe.
** Stock down as much as 7.3 pct, biggest one-day percentagedrop since May 2013.
** Trading volume at more than half its 30-day daily averageafter only an hour's trade.
** Forecasts have been under pressure. In past 30 days, 2 of13 analysts have lowered FY EPS estimates for Synthomer with anaverage cut of 1.6 pct, StarMine shows.
** Sharply underperforms sector peers Victrex,Croda Intl & Johnson Matthey, all broadly flaton the day. (RM: tricia.wright1.thomsonreuters.com@reuters.net)