The chemical sector was the best-performing category in London on Monday with Yorkshire-based Croda International providing a lift after an upgrade from Deutsche Bank.Deutsche Bank lifted its rating for Croda from 'hold' to 'buy' and hiked its target price from 2,350p to 2,800p, causing shares to advance 4.4% to 2,561p.FTSE 250-listed Croda is divided into three main segments: consumer care, performance technologies and industrial chemicals.With top-line growth having slowed over the past two years and underperformed some its other peers in the sector, Deutsche Bank reckons that growth is "set to resume", leading to a re-rating of the stock."The stock has de-rated versus the sector and at 16.3 times 2016 estimated earnings, we see the valuation as relatively attractive given the niche growth, pricing power, best-in-class returns and scope for share buyback,"Sector peer Johnson Matthey was also on the rise, up 0.8% as the stock extended gains made last month after impressing the market with its half-yearly report. The shares rose around 13% over November alone.Interim revenues at the sustainable technologies and chemicals firm declined by 25% due to the loss of an important contract with Anglo American Platinum, but the company still hiked its dividend by 9% after underlying profits improved by 2%.Scapa was also in demand, rising nearly 4%. The maker of bonding materials reported last week that first-half adjusted profits improved by 14% on the back of a "strong performance across all our divisions and regions". The company said it would deliver full-year results above market expectations.Chemicals peers Alent, Hardide, Revolymer and Plant Health Care were performing well on Monday. Top performing sectors so far todayChemicals 10,896.20 +1.03%Technology Hardware & Equipment 1,113.76 +0.25%Electricity 10,238.65 +0.08%Bottom performing sectors so far todayIndustrial Metals & Mining 1,449.23 -3.13%Mobile Telecommunications 5,104.10 -3.02%Industrial Engineering 8,501.30 -1.97%Tobacco 42,769.07 -1.87%Insurance (non-life) 1,854.85 -1.85%