1: 32 percent / 85 aq. H3PO4 / 80 h / Heating 2: 100 percent / 1-chloroethylchloroformate / 1,2-dichloro-ethane / a) 0 deg C, 10 min, b) reflux, 1 h View Scheme

in phosphoric acid

phosphoric acid 80 h; Heating;