Diethyl styrene malonate CAS: 20320-59-6. I watched Mr. Barton use 55.66 grams of diethyl phenylacetylmalonate, 7.5 ml of sulfuric acid, 40 ml of acetic acid, and 60 ml of distilled water to heat and reflux for 4-5 hours. Then, extract 50 ml of the combined solution three times with ether, wash with 200 ml of water, and remove the water with sodium sulfate before vacuum distillation