Isomerization of stable olefins using carbon catalyst
Publication Date: 2015-Dec-06
The IP.com Prior Art Database
Xuehui Sun: INVENTOR [+1]
Disclosed are systems and process for the isomerization of halogenated olefins between trans and cis form using a carbon catalyst. An example is given for isomerization and purification of (1E)-1-chloro-3,3,3-trifluoroprop-1-ene (trans-HCFO-1233zd) to (1Z)-1-chloro-3,3,3-trifluoroprop-1-ene (cis-HCFO-1233zd).
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SYSTEMS AND PROCESSES FOR THE ISOMERIZATION OF STABLE
OLEFINS USING A CARBON CATALYST
BACKGROUND INFORMATION Field of the Disclosure
This disclosure relates to an integrated process for the isomerization of stable olefins using a carbon catalyst.
Description of the Related Art
Certain geometric isomers of halogenated olefins are more preferred than others in certain embodiments. For example, the cis-form of
1-chloro-3,3,3-trifluoroprop-1-ene to is more preferred as an additive in certain foam and refrigerant applications than the trans-form. It is recognized that many of the current processes for producing halogenated olefins, produce a mixture of the geometric isomers at various percentages of each form.
In the industry, cis-1-chloro-3,3,3-trifluoroprop-1-ene is formed as a by-product of manufacturing the "trans" isomer. However, this is not cost effective or an efficient means to obtain the desired isomer. Methods and systems regarding the isomerization olefins exist, e.g. U.S. Patent Nos. 8,288,598 (and its progeny) and 7,563,936 to Honeywell International Inc.
(New Jersey) provide instructions for specific olefins based on defined conditions.
A need exists for processes which are capable of converting a thermodynamically favored halogenated olefin isomer to a more desirable isomer. In particular, a process is needed to isomerize stable olefin
compounds by using a carbon catalyst without the necessity of the presence of hydrofluoric acid for isomerization.
BRIEF DESCRIPTION OF THE FIGURE
FIG. 1 is Integrated process schematic for isomerization and
purification of (1E)-1-chloro-3,3,3-trifluoroprop-1-ene (trans-1233zd) to (1Z)-1-chloro-3,3,3-trifluoroprop-1-ene (cis-1233zd).
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DETAILED DESCRIPTION Disclosed are systems and perpetual processes for the isomerization of halogenated olefins using a carbon catalyst.
In a first embodiment, the present invention is directed to a system
for the perpetual isomerization of stable olefins using a carbon catalyst including, providing a carbon catalyst to a reactor in conditions effective to isomerize a halogenated olefin from the favored isomer form to the thermodynamically non-favored isomer form. The system will be effective for any compound that can be at least fractionally isomerized to a less
thermodynamically favorable isomer (i.e. HFO-1234ze, CF3CH=CHF).
The conversion of isomerization at a certain temperature is limited by the equilibrium concentration at that temperature. Equilibrium will shift with a change of temperature; however, the catalyst will not change the equilibrium concentration but promotes the rate to achieve the equilibrium
concentration. The rate of isomerization is affected by the catalyst, contact time, temperature and pressure, and is limited by the equilibrium concentration at a defined temperature.
A fundamental concept of this invention is that there is an equilibrium which exists between the Z and E isomer of stable ole...