Liquid media containing Lewis basic reactive compounds for storage and delivery of Lewis acidic gases
View Patent ↗This invention relates to an improvement in a low-pressure storage and delivery system for gases having Lewis acidity, particularly hazardous specialty gases such as BF 3 and diborane, which are utilized in the electronics industry. The improvement resides in storing the gases in a liquid incorporating a reactive compound having Lewis basicity capable of effecting a reversible reaction between a gas having Lewis acidity. The reactive compound comprises a reactive species that is dissolved, suspended, dispersed, or otherwise mixed with a nonvolatile liquid.
1. In a process for storage and delivery of a gas, within a storage and delivery system comprised of a vessel containing a medium capable of storing a gas, and permitting delivery of said gas stored in said medium from said vessel, the improvement which comprises:
storing a gas having Lewis acidity in a reversibly reacted state within a liquid medium incorporating a liquid carrier and a reactive compound having Lewis basicity.
2. The process of claim 1 wherein the liquid carrier has a vapor pressure below about 10 −2 Torr at 25° C.
3. The process of claim 1 wherein at least 50% of the stored gas is removable within a working pressure range of from 20 to 760 Torr at a temperature from 20 to 50° C.
4. The process of claim 1 wherein the liquid carrier is an ionic liquid.
5. The process of claim 1 wherein the Lewis acidic gas is selected from the group consisting of boron trifluoride, diborane, borane, silicon tetrafluoride, germanium tetrafluoride, germane, phosphorous trifluoride, phosphorous pentafluoride, arsenic pentafluoride, sulfur tetrafluoride, tin tetrafluoride, tungsten hexafluoride and molybdenum hexafluoride.
6. The process of claim 1 wherein the reactive compound incorporates Lewis base functionalized monomers selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polyvinyl amine, polyaryl sulfone, polyphenylene sulfide, polyacrylic acid, polyvinyl alcohol, polymethyl vinyl ether, polymethyl vinyl ketone, polyaniline, polypyrrole, polythiophene, polyvinyl pyridine, and oligomers and copolymers of ethylene oxide, propylene oxide, acrylic acid, alkyl acrylates, alkyl methacrylates, acrylamide, acrylonitrile, methyl vinyl ketone, methyl vinyl ether, and 4-vinylbenzonitrile.
7. The process of claim 6 wherein the reactive compound has a vapor pressure below about 10 −2 Torr at 25° C.
8. The process of claim 1 wherein the ΔG rxn for the reactive compound and Lewis acidic gas is from −0.5 to −1.6 kcal/mol at room temperature.
9. The process of claim 1 wherein the Lewis acidic gas is selected from BF 3 , SiF 4 , GeH 4 , and GeF 4 .
10. The process of claim 9 wherein the reactive compound is polyacrylonitrile.
11. The process of claim 10 wherein the liquid carrier is selected from BMIM+PF 6 − and BMIM+BF 4 − .
12. The process of claim 1 wherein the reactive compound is a Lewis basic anionic compound selected from the group consisting of alkoxide, aryloxide, carboxylate, halide, sulfonate, sulfate, borate, phosphate, and arsenate.
13. The process of claim 1 wherein the reactive compound is a salt of an anion selected from the group consisting of RO − , CH 3 CO 2 − , HCO 2 − , Cl − , Br − , R 2 N − , CN − , SCN − , NO 2 − , NO 3 − , FSO 3 − , CF 3 SO 3 − (OTf), RSO 3 − , ROSO 3 − , ClO 4 − , BF 4 − , BR 4 − , PF 6 − , PR 3 F 3 − , AsF 6 − , and SO 4 2− , where R is alkyl, cycloalkyl, aryl, alkoxy, aryloxy, haloalkyl, haloalkoxy, or a polymer.
14. The process of claim 13 wherein the counterion of such salt is comprised of an inorganic or organic cation selected from the group consisting of Na + , K + , Li + , Mg 2+ , Ca 2+ , Ba 2+ , NH 4 + , R 3 NH + , NR 4 + , R 3 PH + , PR 4 + , N-alkylpyridinium, N,N′-dialkylimidazolium, pyridazinium, pyrimidinium, pyrazinium, pyrazolium, pyrrolidinium, triazolium, thiazolium, and oxazolium.
15. The process of claim 14 wherein the reactive compound is selected from the group consisting of Ca(O 2 CH) 2 , Mg(O 2 CCH 3 ) 2 , BaSO 4 , Na 2 SO 4 , KOCH 2 CH 3 , LiN(SO 2 CF 3 ) 2 , KSO 3 CF 3 , AgSO 3 CF 3 , NaClO 4 , [(CH 3 CH 2 CH 2 CH 2 ) 4 N][BF 4 ], [(CH 3 CH 2 CH 2 CH 2 ) 4 N][SO 3 CF 3 ], [(CH 3 CH 2 CH 2 CH 2 ) 4 N][OCH 2 CH 3 ], [(CH 3 ) 4 N][SO 3 CH 3 ], [(CH 3 ) 4 N][CN], [(CH 3 ) 4 N][CH 3 SO 3 ], [(CH 3 ) 4 N][ClO 4 ], [(CH 3 ) 4 N][SCN], [(CH 3 CH 2 ) 4 N][OH], [(CH 3 CH 2 ) 4 N][Cl], and [(CH 3 CH 2 ) 4 N][Br].
16. The porocess of claim 1 wherein the reactive compound is 1-(3-cyanopropyl)-3-methylimidazolium tetrafluoroborate.
17. The process of claim 16 wherein the liquid carrier is selected from BMIM+PF 6 − and BMIM + BF 4 − .