200 u00b0 c and held for 5 min the method used for gc ms is as follows the initial oven temperature is 40 u00b0 c and is held for 1 min the temperature is ramped at 15 u00b0 c min up to 290 u00b0 c and held for 7 min the total time elapsed is 25 min the injector temperature is 290 u00b0 c with a split of 20 1 the helium flow rate is 0 5 ml min the temperature of the transfer line is 220 u00b0 c the mass scan is 35 650 da sec the identification of products is predicted by gc ms library and confirmed by 1 h nmr and the retention time of gc retention times of the products in gc using the method described above are dmthf 4 6 min and 4 8 min 1 h nmr is used to determine the yield of dmthf by using nitromethane as internal standard the procedure of example 1 is employed except that the oil bath has a temperature of 80 u00b0 c to enable reaction of the mixture at 80 u00b0 c the procedure of example 1 is employed except that the oil bath has a temperature of 100 u00b0 c to enable reaction of the mixture at 100 u00b0 c the procedure of example 1 is employed except that 4 ml benzene is added to the mixture before the reaction and the oil bath has a temperature of 80 u00b0 c to enable reaction of the mixture at 80 u00b0 c the procedure of example 1 is employed except that 4 ml benzene and 0 6 g nacl each are added to the mixture before the.