A process for the production and purification of 2,3,3,3-tetrafluoropropene (HFO-1234yf) carried out starting from a starting composition comprising at least one compound of formula (I) CH(n+2)(X)m—CHp(X)(n+1)—CX(3+p−m), where X independently represents F or Cl;
- n, m and p are, independently of one another, 0 or 1 with n+m=0 or 1, n+p=0 or 1 and m−p=0 or 1, at least one X being Cl;
- said process comprising the stages of:
- a) bringing the starting composition into contact, in the presence of a catalyst, with HF under conditions effective in producing a composition A comprising HCl, a part of the unreacted HF, 2,3,3,3-tetrafluoropropene (HFO-1234yf), intermediate products B comprising 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf), 1,1,1,2,2-pentafluoropropane (HFC-245cb) and trans-1,3,3,3-tetrafluoro-1-propene (HFO-1234zeE) and byproducts C comprising trans-1-chloro-3,3,3-trifluoro-1-propene (HCFO-1233zdE), cis-1-chloro-3,3,3-trifluoro-1-propene (HCFO-1233zdZ), cis-1,3,3,3-tetrafluoro-1-propene (HFO-1234zeZ), 1,1,1,3,3-pentafluoropropane (HFC-245fa), 2-chloro-1,1,1,3,3-pentafluoropropane (HCFC-235da), 1,2-dichloro-3,3,3-trifluoropropene (HCFO-1223xd), 2-chloro-1,3,3,3-tetrafluoropropene (HCFO-1224xe), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa) and optionally one or more compounds of formula (II) CnHxFyClz in which n=4, 5 or 6, x is an integer from 0 to 6, y is an integer from 4 to 12, z is an integer from 0 to 6, with 2n=x+y+z if w is 1 or 2n−2=x+y+z if w is 2 or 2n+2=x+y+z if w is 0, w being the number of unsaturations in the compound of formula (II) considered;
- b) recovering and purifying said composition A in order to form and recover a gas stream G1 comprising HCl, 2,3,3,3-tetrafluoropropene (HFO-1234yf), a part of the unreacted HF, a part of the intermediate products B and a part of the byproducts C;
- and a stream, which is liquid, L1 comprising a part of the unreacted HF, a part of the intermediate products B and a part of the byproducts C;
- wherein said gas stream G1 is purified by the following stages:
- b1) distilling the gas stream G1 in order to recover a stream G1a comprising HCl and a stream G1b comprising 2,3,3,3-tetrafluoropropene (HFO-1234yf), a part of the unreacted HF, said a part of the intermediate products B and said a part of the byproducts C;
- b2-1) distilling said stream G1b obtained in stage b1) under conditions effective in forming a gas stream G1c comprising 2,3,3,3-tetrafluoropropene (HFO-1234yf), a portion of said part of said unreacted HF, a portion of said part of the intermediate products B and a liquid stream G1d comprising a portion of said part of the intermediate products B and said part of the byproducts C and a portion of said part of said unreacted HF;
- and
- b2-2) distilling said stream G1d obtained in stage b2-1) under conditions effective in forming a stream G1d′ comprising said portion of said part of the intermediate products B, said portion of said part of said unreacted HF and a portion of said part of the byproducts C comprising cis-1,3,3,3-tetrafluoro-1-propene (HFO-1234zeZ), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa) and a part of trans-1-chloro-3,3,3-trifluoro-1-propene (HCFO-1233zdE) and 1,1,1,3,3-pentafluoropropane (HFC-245fa);
- and a stream G1d″ comprising a portion of said part of the byproducts C comprising cis-1-chloro-3,3,3-trifluoro-1-propene (HCFO-1233zdZ), 2-chloro-1,1,1,3,3-pentafluoropropane (HCFC-235da), 1,2-dichloro-3,3,3-trifluoropropene (HCFO-1223xd), 2-chloro-1,3,3,3-tetrafluoropropene (HCFO-1224xe), and optionally one or more compounds of formula (II) CnHxFyClz in which n=4, 5 or 6, x is an integer from 0 to 6, y is an integer from 4 to 12, z is an integer from 0 to 6, with 2n=x+y+z if w is 1 or 2n−2=x+y+z if w is 2 or 2n+2=x+y+z if w is 0, w being the number of unsaturations in the compound of formula (II) considered.