High-purity 1,1,1,2,3,3-hexafluoropropane, method for producing same and use thereof

Abstract

The present invention relates to a method for producing high-purity 1,1,1,2,3,3-hexafluoropropane and a composition containing mainly 1,1,1,2,3,3-hexafluoropropane, suitable for use as a cleaning agent in the semiconductor industry.

Claims

1. A composition comprising at least 99.9% by weight of 1,1,1,2,3,3-Hexafluoropropane (HFC-236ea), and one or more compounds selected from the group consisting of hexafluorocyclopropane (cyclo-C.sub.3F.sub.6) and octafluorocyclobutane (cyclo-C.sub.4F.sub.8), wherein the one or more compounds is present in the composition in an amount of at most 500 ppm.

2. The composition of claim 1, wherein the one or more compounds is present in the composition in an amount of at most 50 ppm.

3. The composition of claim 1, wherein the composition further comprises HF in an amount of at most 1 ppm.

4. The composition of claim 1, wherein the composition further comprises water in an amount of at most 190 ppm.

5. The composition of claim 1, wherein the composition further comprises hydrogen in an amount of at most 5 ppm.

6. The composition of claim 1, wherein the composition further comprises nitrogen in an amount of at most 70 ppm.

7. The composition of claim 1, wherein the composition further comprises oxygen in an amount of at most 20 ppm.

8. The composition of claim 1, wherein the composition further comprises carbon dioxide in an amount of at most 20 ppm.

9. The composition of claim 1, wherein the composition further comprises carbon monoxide in an amount of at most 15 ppm.

Description

EXPERIMENTAL SECTION

(1) Test 1

(2) 325 g of a mixture (previously washed) comprising about 97.8% by weight of HFC-236ea are charged to a piece of jacketed glass distillation equipment (cooled to −20° C.), equipped with an “Oldershaw” column with approximately 10 theoretical plates, surmounted by a reflux condenser, said mixture having the following composition:

(3) TABLE-US-00001 TABLE 1 Concentration Compound (% by weight) 2,3,3,3-tetrafluoropropene (HFO-1234yf) 0.0984 1,3,3,3-tetrafluoropropene (HFO-1234ze) 0.0013 1,1,1,2,3,3,3-peptafluoropropane (HFC-227ea) 0.0117 1,1,1-trifluoropropane (HFC-263fb) 0.0019 1,1,1,3,3,3-hexafluoropropane (HFC-236fa) 0.0246 1,1,1,2-tetrafluoropropane (HFC-254eb) 0.0581 HFC-236ea: 97.8667  1,1,1,3,3-pentafluoropropane (HFC-245fa) 0.4825 1,1,1,2,3-pentafluoropropane (HFC-245eb) 1.3576 1,1,1,4,4,4-hexafluoro-2-butene (HFO-356mff) 0.0244 1,1,1,3-tetrafluoropropane (HFC-254fb) 0.0728

(4) The distillation is carried out at atmospheric pressure. A total of 12 fractions are drawn off with a head temperature of 10° C.

(5) Table 2 summarizes the composition in % by weight of fractions 2 to 11.

(6) TABLE-US-00002 TABLE 2 Component #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 17.1 g 35.0 g 51.2 g 42.4 g 26.3 g 17.1 g 12.8 g 16.2 g 31.3 g 16.7 g HFC- 0.0708 0.0247 0.0063 0.0013 0.0004 0.0001 227ea HFC- 0.0043 0.0032 0.0024 0.0016 0.0015 0.0004 0.0011 0.0009 0.0005 0.0003 263fb HFC- 0.1053 0.0644 0.0319 0.0157 0.0075 0.0093 0.0040 0.0025 0.0011 0.0007 236fa HFC- 0.1394 0.112 0.0852 0.0599 0.0458 0.0417 0.0269 0.0193 0.0113 254eb HFC- 99.6147 99.7282 99.7754 99.7942 99.7760 99.7572 99.7219 99.6821 99.5781 99.1932 236ea HFC- 0.0451 0.0486 0.0681 0.0831 0.1137 0.1216 0.1457 0.1874 0.2538 0.4694 245fa HFC- 0.0188 0.0188 0.0307 0.0441 0.054 0.0698 0.0826 0.0987 0.1433 0.3176 245eb HFC- 0.0004 0.0008 0.0014 0.0026 0.0046 356mff

(7) The fractions of purity>99.7% are pooled and dried by passing over a 4 Å molecular sieve to form a final batch.

(8) Analysis of this final batch indicates an HFC-236ea purity>99.7% by weight with a water content of 11 ppm. No trace of acidity is detected.

(9) Test 2

(10) A gas stream comprising 99.8% by weight of HFC-236ea, 217 ppm of HF, 27 ppm of water is passed through a bed (length/diameter ratio=10) of BASF HF-200 alumina spheres (⅛″ spheres) and a siliporite molecular sieve bed with a pore size of 3 Å for 8 hours at ambient temperature. The stream at the outlet is virtually free of HF (<1 ppm) and of water (<10 ppm).