Assemble a flat-bottomed flask fitted with a wide-bore condenser 80 to 90 cm long, a separating funnel and a mechanical stirrer. Support the whole setup on a hot plate 10 cm below it.
Add 2 g of vanadium pentoxide, 450 g of sodium chlorate and 1 liter of water to the flask and start stirring. Heat the mixture to 70 to 75 degrees and add 5 to 10 cc of the 200 g of fulfural. A rigorous reaction starts. Add the remaining fulfural in small amounts over 70 to 80 minutes.
Heat the entire mixture to 70 to 75 degrees with constant stirring for 10 to 11 hours. Allow the mixture to stand overnight at room temperature to form fumaric acid. Filter the crude fumaric acid with suction and dry in the air.
Concentrate the filtrate by heating it on a water bath with 50 cc of concentrated hydrochloric acid. Observe the color of the solution turning blue at the end of the reaction. Concentrate the solution to 700 cc and cool it with running water. Filter with suction and dry in the air.
Purify samples from step 3 and 4 by dissolving it in 1,250 to 1,300 cc of 1N hydrochloric acid. This produces fumaric acid, about 120 to 138 g, yield 50 to 58 percent, that melts at 282 to 284 degrees.