Process for purifying crude gaseous hydrogen chloride

A process for the purification of crude gaseous hydrogen chloride which contains as impurities silanes containing chlorine and/or organic radical, alkanols, water, chlorinated hydrocarbons, hydrocarbons, and organic acids, by condensation, compression and fractional distillation, which comprises (1) passing the crude gas through a heat exchanger, in which it is cooled to -15.degree. C. to -35.degree. C.;

• (2) subsequently heating the crude gas which has been at least partially freed from condensable products to 0.degree. to -40.degree. C., compressing it in a screw compressor with oil injection to a pressure of 0.6 to 1.5 MPa, separating off the hydrogen chloride from the oil through a separator having a filter, cooling the oil which has been separated off in a heat exchanger, freeing it from residues through a filter web, and recycling it to the compressor;
• and (3) subsequently fractionating the compressed hydrogen chloride which has been separated from the oil in a distillation column under pressure and discharging the purified hydrogen chloride at the top of the column. PG,12