An azeotrope containing HF and 1233zd is provided, as are methods for separating this azeotrope from mixtures of HF and 1233zd which are HF-rich or 1233zd-rich and methods for making use of the azeotrope and separation methods to improve processes for preparing 1233zd, an intermediate used in the preparation of 245fa. 245fa is a known foam blowing agent and refrigerant.