DUBAI, July 3 (Reuters) - Saudi Basic Industries Corp (SABIC), one of the world's largest petrochemical firms, has proposed paying a cash dividend for the first half of 2014 of 2.5 riyals ($0.67) per share, it said in a bourse filing on Thursday. The proposed figure is higher than the 2 riyals per share that the company paid in the corresponding period of 2013, according to Thomson Reuters data. ($1 = 3.7504 Saudi Riyals) (Reporting by David French; Editing by Pravin Char)