Clean Technol., Vol. 24, No.1, M학낭1 2018, pp. 15-20

재자원확기솔

Rational Design of Extractive Distillation Toward Enhance이 Separation of HFPO from HFP/HFPO Mixture

Yongtaek Lee * Department of Chemical Engineer때， Chung따mN와ional U피.veπity

99 Daehak-m, Yuseong-gu, Daejeon 34134, Korea

(Rcceπed for review August 1, 2017; Revision received August 22, 2017; Accepted August 23, 2017)

Abs1ract

Hcxafluor야π'Opyleneoxide (C3F60, HFPO) is 비맹ly cxpensive and it may be 뻐ed as a raw material fiπ the synthesis of V ar10US

fluorine b없ed COl뼈ounds. curr뼈tly， cx뼈ctive 해뼈llation method has g，입ned COllSiderable &ttention to colle따 the HFPO from a mixture of HFPO / hexatluor야JroPylene (C3F6, 1표P). optim뼈doper뼈ngcon띠.tions are 양뼈ied using a theoreti때lmethodfor the extr훌ction process. Among av밍lable solvents for the purification process, the use of 1，I-dichlom-l-tl1JOJ'Oetha끄e exhJbits a highp따ityofHFPO 없 a top product and min뼈ize there엔파ed heat duty. Since the boiling point of1lte solvent increases as 1lte press파e in the column increases, the enhanced cx'없ctive capability of the solvent 100 to the high purity of HFPO at the high press따'C.

Keyv빼πIs : Hcxafluoropropyleneoxide, Hexafluompropylene, 앓@없tive di뼈llation， Sep없tion， Aspen

1.lntroduction

As one of the oonse댄lences of the technica1 scarci양 and

energy cri앙S， 않veral efforts 1i:π recyc1ing ftuor띠a뼈 COII껴posites

뼈s been paid to proφlCe tluorin웅based pr뼈없yb띠l벼ng block

[1]. Hexatlu‘>ropropyleneoxide 앙IFPO) is an impor뻐nt pr뼈와y

h피l벼ng block for the synthesis of a vast number of va1u용

뼈ded intl하mediates in organofluorine ch없nistry (i.e. , fluoro­

polymers) in inl뼈S미.al 학끼P파ations (i.e., anti-retlectimν@흙Iprint ∞ating material, membranes in fuel cells, fluorine-based luOO­

cants etc.) [2-6]. Hexafluoropr야영Iene (HFP) 뻐 one of the main

sources to produce HFPO via thermal cracking of polytetra­

fluoroethylene (PTFE) [4，꺼 . The 1표꺼PO can be synthesized by

oxidation of such obtain때 HFP with 80 - 90 ~‘ yields, in­

dicating that the remained HFP shm피d properly be separated

andlor removed to produce high p따ity lIFPO.

Neg1igibly sm외1 difference in boi1ing points (ATbp :::: 2.3 'C)

betw뼈 뾰P (-27.3 'C) and 班PO (-29.6 'C) at 1 뼈， h%evtI,

has hamp하ed their effective separation using convention.a11y

얼끼plied regular dis비lation process [8]. Therefore, strate.믿.es f(π

proper solving this is뻐e shou1d tar뿜t another 앓맹ration proces8.

One of the promising methods to remove HFP species from a

HFP.까g‘PO mixture can be an extractive di엄llation method [9].

• Towhomcone뼈g떠ence 뼈0띠.d be addressed. E뼈il: ytlce@cnu.ac.kr; Tel: +82-42-821-5686; Fax: +82-42-822-8995

doi: 10.7464lksct.2018.24.1.015 plSSN 1598-9712 elSSN 2288-0690

Since the vapcπ pressurc엉 ofHFP 밍ld 1표1pO are 댄rite similar, the relative vol뼈lity is about to be 1. Th하엉bre， it is necessary

to lower the vapor pressure of HFP by adding a solvl야t80 뼈t

the relative volatility is increased. In order to successfully ac­

hieve such extractive disti11ation, proper selection of solvent

빼0띠d firstly be accm때aoi뼈 [10]. The key factors for solvents

as an extracting agent are high vola벼ity， needless of stabi.]iz(π，

recyclable, low ∞st， nonfl없nmable， and environmentally b뼈ign.

And then, the ~뼈rating ∞n‘lition 빼ould be φtimized πoperly.

In thls study, l ， l-dic비.oro-l-fluoroethane， dichloromethane, and diisopropyl ether were applied 없ld comp없뼈 as extractive

solvents to maximize the purity of HFPO with m뼈m따 ene영Y

COI영umption 앓 a function of inlet press따e using Aspen Plus

software. one of the most inφortant φ@뼈ngp없'8Il1앙ers seems

to be the proper selection of ex뾰ctive 8Olvents. After’ 뼈쩍뻐te

choice of solven뼈， the next αmsideration is how to minimiz용 the

scale of the 앓뾰.ctive distillation tower in terms of the number

of s뼈.ges and the di없ne뼈 of the tower. To achieve the .goa1,

two factors may be considered: the reflux ratio 없ld the mass

flow rate of the solvent. on the other 뼈nd， the 야x:rating cost

is 따so important: the heat φlties for the reboiler 와ld the con­

d해ser should be taken into account. Th앙efore， this theoretica1

돼is is an Open-Access arti.cle 벼밟ibuted undcr tbe 야ms ofthc α"Cativc commons Attribution No바:omm.:π뻐1 Liccnsc (http :ν.crcativccommons.O때i.ccncc밍

by-.뼈.0) which pcrmits unrcstrictcd non-commcrcìal usc, distribution, an.d repmduction in 없y mcdium, pm찌ded thc ori맹al work is propcrly cìted

15

16 Yo뺑aekLee

study focuses on the following targets: optimizing operation

parameters such as (1) the type of extractive solvents, (2) the

reflux ratio, (3) the number of tray, and (4) the mass flow rate

of solvents.

2. Material and Methods

2.1. Physical properties of HFP and HFPO

Table 1 shows the molecular weights, molecular structures

and the normal boiling points of HFP and HFPO. Both the

molecular structure and the normal boiling point are quite

similar between HFP and HFPO, indicating that the separation

of these molecules from their mixture is hampered.

Variation of temperature and pressure with respect to the

mole fraction of HFP is described in Figure 1. The dew point

of a vapor is located quite near from the bubble point of a liquid

at any given mole fraction of HFP. It indicates that a normal

distillation cannot be successfully used to separate them and

another type of distillation such as an extractive distillation has

to be considered.

Typical organic materials were chosen as an exπactive solvent

which has a relatively low boiling point compared to HFP and

HFPO so that it can easily be recovered from the mixture of

HFP, HFPO, and solvent after the ex없띠ve distillation. It should

not form an azeotropic solution together with either HFP or

HFPO. The solvent has to be an inert material during the syn­

thetic reaction of HFPO. The physicochemical properties are

shown in Table 2.

2.2. Computational modeling

The mixture of HFP and HFPO is supplied to the extractive

distillation column 1 so that the pure HFPO can be obtained as

a top product and the mixture of HFP and the solvent can be

To ble 1. Physica1 properties of HFP and HFPO

(a) 303

흐 302

‘-m ‘­그 에 ..... ro 301

‘-φ Q.

E }오 300

299

(b) 6.8

E •-‘

6.7

~ 6.6

@

‘-그 % 65 φ

‘-ι 6.4

6 .3

t-x HFP

t -YHFP

0.0 0.1 0.2 0 .3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Liquid/Vapor mole fraction of HFP

p-xHFP

P -YHFP

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.。

Liqu id/Vapor mole fraction of HFP

Figure 1. Gas-1iquid phase equi1ibrium ofHFPIHFPO with respect to (a) temp앙ature and (b) press따e.

separated as a bottom product as shown in Figure 2.

The solvent is recycled to the first column after it is sep없ated

from the mixture of HFP and the solvent using a normal dis­

tillation column. The Aspen Plus software is used to design the

extractive distillation process: the number of trays, the reflux

Component Chemical formula MW(gmor1) Boiling point (OC) Chemical structure CASNo.

Hexafluoropropylene (HFP) CF2CFCF3 150.02 -29.6 Ff4i:Z 116-15-4

Hexafluoropropyleneoxide (HFPO) CF3COCF3 166.02 -27.3 F-t-8-t-F 684-16-2

Toble 2. Physical properties of solvents

Solvent Chemical formula Aspenform MW(gmor1) Boiling point (OC)

, 1-dichloro-1-fluoroethane CChFCH3 C2H3ChF 116.95 32.0

Dichloromethane CH2Ch CH2Ch 84.93 39.8

Diisopropyl ether CH3CH(CH3)OCH(CH3)2 C6H140 102.18 68.3

Rational Design ofExtractive Disti11ation Toward Enhanced Separation ofHFPO from HFP/HFPO Mixture 17

solvent

HFP

HFP + HFPO

Figure 2. Layout of columns for extractive disti11ation and recyc1e of solvent.

ratio, the type of condenser, the locations of the feed and the

solvl없lt， the column pressure, the feed flow rate, the solvent flow

rate, the type of solvent, the purity of HFPO, the heat duties

of the condenser and the reboiler, etc. A proper equation of

state for the given gas is chosen so as to predict the separation

behavior well. Both the shortcut modeling of DSTWU/ Aspen

Plus and the rigorous modeling simu1ation of RADFRAC/ Aspen

Plus are utilized together. The target purity of HFPO is set to

be 0.98 in terms of mole fraction. The purity of HFPO was

calculated as a function of the solvent flow rate together with

Table 3. A typical condition for numerical analysis

Number of trays in extractive column 30

Column pressur (atm) 2 ~ 10

Reflux ratio 10

Solvent 1, l-dichloro-l-fluoroethane

Flow rate of feedstock (kg d-1 HFPO 227.2

HFP 22.8

Flow rate of solvent (kg d-1) 200 ~ 100,000

Case 2 3 4 5 6

Solvent feed tray 5 10 15 5 10 5

Feed tray 15 20 25 20 25 25

several parameters such as the type of solvent and the reflux

ratio. The heat duties of the condenser and the reboiler are also

simu1ated with the s따ne condition. A typical operating condition

for a numerical analysis is represented in Table 3.

3. Resulfs and Discussion

A type of condenser is fixed to be a partial condenser since

the top product is collected as a gas so that it can be directly

used as an intermediate in the industrial organofluorine chemistry:

specifically as a monomer for fluoropolymers. Also several

design variables are fixed such as the number of trays of the

extractive disti11ation and the operating pressure by a preliminary

design with Aspen Plus so that the required heat duty is con­

trolled to be minimized.

3.1. Effect oftray location for feedstock on purity of HFPO

At the given opera바19 condition shown in Table 3, the purity

of HFPO was simu1ated and the resu1ts of it is shown in Figure

3 as a fimction of flow rate of extractive solvent. πle 1, l-dich1oro-

1-fluoroethane was selected as a model solvent to investigate

the optimum locations of both a feed and a solvent tray in the

extractive distillation column. At the moderate flow rate of sol­

vent, the p따ity of HF‘PO was targeted to be higher than 0.98 in

18 Yongtaek Lee

1.00

______..__ Case 1 。 Case 2

---v--- Case3 - -.A. - - Case4 - __ - Case5

- - 11- - Case 6

0.90

2OxJ03 4OxJ03 6OxJ03 8OxJ03 10OxJ03

Flow rate of solvent I (kg day-1

Figure 3. HFPO P따ity as a function of flow rate of 1, l-dichloro-1-fluoroethane under various positions of feedstock and solvent tray.

mole fraction. The results show that the Case 1, Case 4 and

Case 6 (see Table 3) are suitable to obtain the target purity of

HFPO at over the solvent flow rate of 200 kg d-1. Therefore, the solvent tray was fixed to be 5 and the feed tray can be se­

lected among 15, 20, and 25 depen띠ng on the reasonable con­

struction of the distillation column. In 깐lÏs study, the tray number

of 20 was selected as a feed tray.

3.2. Screening of solvents

In order to determine the solvent for an efficient extractive

distillation of HFP/HFPO mixture, the purity of HFPO were

calculated with respect to the mass flow rate of 1, l-dichloro­

l-fluoroethane, dichloromethane, and diisopropyl ether, respec­

tively, as shown in Figure 4. the p따ity of HFPO for all solvents

increased as the increase in the mass flow rate, which indicates

that the process toward the purification of HFPO is underlying

the steady-state. Although the recorded purities of HFPO for

diisopropyl ether and dichloromethane were higher than that for

the 1, l-dichloro-l-fluoroethane at 5 atm and 10 atm, respec­

tively, the gap of the purity was ne생i밍bly low (2 ~ 5%). In other

words, all of the extractive solvent candidates exhibit comparable

performance toward the purification of HFPO. It should be

noted that the level of HFPO purity is over 0.85 at 5 atm, 0.917

at 7 atm, and 0.945 at 10 atm, which are hi양1 enough to reach

theprim따y target purity of HFPO. Therefore, examination and

comparison of the applied heat at reboiler (bottom) and ex­

changed heat 따 cond없lser (top) in the column for theses solvents

is important for practical application.

3.3. Heat duties for condenser and reboiler

πle heat duties on the condenser and the reboiler depend on

the various operating parameters, particularly the type of the

(a) 1.00

。

ι 0.95 ι ____ .. -'Y"_，，_~- ... 一...... ...-폰 ---~ ... 추 ........... -’추-" 。--.-~-...-’ C 0.90 i ............ 。

Q

띤 0.85 나-

___._ 1.1 -d ichloro- 1껴uoroetha

오 .. 0 ... Dκhlorom빼ne 。- .. - Diisopropyl ether

~ 0.80ι • / •

0.00 +-7/"1 o 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500

Mass f10w rate of solvent (kg day-1)

(b) 1.00

。 n QR

ι LL

포 0.96 。

I 으 0.94 Q

띤 나- 0.92 @ 。

~ 0.90μ/ • o 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500

Mass flow rate of solvent (kg day-1)

。。-%

혀

J lf

해

4 nJ g * * 갯

lι

fυ

lo r 。

rr

。。 ___._ 1,1-dichloro-1-fluoroethane

。 Dichloromethane

-~- Diisopropyl ether

y1녁 뼈

(V

}

뼈

。

-、，

l

r ‘~4

4,

“

F

째 때‘

。

} 때 9

。

-<꽤 。

(v

-

얘

「뼈 때

1

f

|

J

一

{

떠 잉

。

,

-&

tl

。*

• g

。

3

*

{

￠ *뼈

￠ F

{

때 W

(ι r

}

때 m

션 쉰

『뼈 원

。

l

-대 M

% Jr

ν{ m

------

y4+ o

m

%

%

인 %

%

%

M었혀 m없ιιι

히잉， 。gα또ι工 }견。

:=g틀으.i힘Qam띤」뇨둥}경@웅

5흘

E

ti--、

-•._ 1,1-dichloro-1 -fluoroethane 。… Dichloromethane

- .. - Diisopropyl ether

Figure 4. Changes inHFPOpurityusing 1,I-dichloro-l-fluoroethane, dichloromethane, and diisopropyl ether as solvents with respect to the mass flow rate of the solvents at (떠 5 atm, (b) 7 atm, and (c) 10 atm, respectively.

solvent for the extractive distillation. The heat capacities of the

utilized solvents are different from each other, leading that the

different heat duty is required. Since the heat duty is one of

the major operating costs, the heat duty is designed to be as

low as possible. In Figure 5, the heat duty is represented as

a function of the flow rate of the solvent used at the given

typical condition such as the operating pressure of 5, 7, and

10 atm. It easily can be seen that the lowest heat duty can be

19 Rational Design ofExtractive Distillation Toward Enhanced Separation ofHFPO from HFPIHFPO Mixture

(c) -755 , ι

---、￡ m 르 -760

즘 -765 -0

ro _77 0 Q) ’‘ •

.s::.

‘-Q) -77.5 ω I Q) -0 -78_0 I 。

Ü -78_5~ o 2002202402602뻐 300320 340 360 380 400 420 ‘40460480500

Mass flow rate of solvent (kg day-1)

。o 0 O ' 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 。

(b) 혀 0 --、z m 르 4 ‘ 5

〉、-=: 용5.0

iS I 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 。~ I e-. 잃 용55

.s::.

‘-Q) -86.0 m z φ

-0 -86.5 I 。

ü 용7.0 o 200 220 2‘0260 280 300 320 340 360 380 400 420 “ 0460480500

Mass flow rate of solvent (kg day-1)

~ I . ' -dlchloro.l ’uoroel’ .. ne 。Otchloromethanø

- ..,.- oi‘。αopylet야r

(a) --、:t:: 울 90.8

승 -91 。

그

E ·912 m @

.s::. -91 .4

‘-φ 일 -91 .6

@

걷 -91 .8 。

Ü -92.0 o 2002202‘0260280300320340360380400 ‘20440460.80 500

Mass flow rate of solvent (kg day-1)

(f) 2000η E ’800 十-← 1 . 1 -dlChloro-l-뻐oroethane ro I 0 Oichloromelhane 르 ’600 ~ - '9 - Ousopropyl ethet'

응 ’400 그 -0 1200

$ 1@O .s::. .._ 800 m B %O

& 4OO

200 t←「o 200 220 240 260 280 300 320 340 360 380 '00 '20 440 '60 480 500

Mass flow rate of solvent (kg day-1)

’ / ~ .... r

’ .K ~ ....

"" .K ~ ..

’ ~.，. , /

’ .K ~ ....

.r' . .,.,..

(e) 1뼈 갚 1뼈 m 르 14애

응 1때

그 -0 1000

없 8애 .s::. .._ 600 @

B 4m @

200 α

o 200 220 240 260 280 300 320 340 360 380 400 420 .40 460 480 500

Mass flow rate of solvent (kg day-' )

x' ~

~ --x' -’ F

x" ~

-~ .. ~ .... x'

~ .. x'

~ .... x' ........

-- ’.1-dichkwo. ' . ftuoroethane 。 Diehloromelhane

- ,.- 01&。α。py l ether

x' _.,. ~ -l

.K ~ ....

",,­x

~.，.

x" ~

-’ x'

-’r J ’I ’ .,.,..

Fig ure 5. Effect of various solvents on heat duties on condenser at (a) 5 atm, (b) 7 atm, and (c) 10 atm, respectively, and also on the reboiler at (d) 5 atm, (e) 7 atm, and (f) 10 atm, respectively.

O o 2002202‘0260 280 300 320 340 360 380 400 ‘20440460480500

Mass flow rate of solvent (kg day-' )

point of 1,1-dichloro-1-fIuoroethane is known to be 32 oC , it is

much lower than 39.8 UC of dichloromethane. The temperature

range will be between 32 UC and -29.6 UC of HFP if 1 ， 1-dic삐oro­

l-fIuoroethane is used. Thus, the temperature range w i11 be

obtained when 1, 1-dichloro-1-fIuoroethane is used among the

three solvents in both the condenser and reboi1er. It should be

noted that the operating temperature is also important in the

distillation tower for the recovery of solvent. Since the boi1ing

__ RR - 2.5

。 RR - 5.0

--‘or--- RR- 10 - -<1 . _ .. RR- 15 ~

500

(b) 100

。

ι 0.96 u. 工‘_ 0.94 。

c::: 0.92 。

(.) ^M ro U.7U ‘-Q) 0.88

。

~ 0.86

ι 0.00 <1-ffi

o 200 250 300 350 400 450

Flow rate of solvent-I (kg day-1)

(a) 100

o 0.95 ι u. 工

‘Õ 0.90

Z 。

:;::: (.) 0 .85 m ‘-‘-@

。 0.80

E

__ RR -2.5

。 RR-5.0

--~-- RR-10 _ . . -<1 . _ .. RR-1 5

ooot

(c) 100

。 0.98ι u. 工‘_ 0.96 。

ζ

:g O94 Q m ‘-Q) 0.92

。

를 0.90#

0.00’+7/‘ o 200 300 400

Flow rate of solvent-I (kg day-1

500 250 300 350 400 450

Flow rate of solvent-I (kg day-1)

‘ & 흠흥:.;..~.용ft??§?fff펀좋ft-용좋 A 으-'융_.-" ^ ,.O 。 υ -

&으iν .... "' ... o .,.o ... 'o,J

V ’ 。 -。

。。

500

Figure 6. The effect ofreflux ratios on the purity ofHFPO with respect to the flowrate of 1,1-dichloro-1-fluoroethane at (a) 5 atm, (b) 7 atm, and (c) 10 atm, respectively.

” 빼

‘” …… “m

·” ‘” “n

빼 m

빼

뼈 짧

÷

。+

얘 뼈 뼈 뼈 뼈 뼈 m

이 (Zm르) 〉5Emφζ」@=g@α

/!ll、

20 yi앵taek Lee

narrower than wi1l1 1he solvent of di뼈orometh뼈e， which is nru대

more effective. Furthermore, the heat of vaporization for 1,1-

dich1oro-1-f1uoroethane is 27.8 kJ mor' and 1I1at for dich10r0-

methane is 28.1 kJ mo1.1 It is believed that the heat duty for

the reboiler with 1,I-dich1oro-1-f1uoroethane in the disti1latioo

∞，hmro 2 will be moch smaller than with di빼10r0metha:0e. As fàr

asthere 생 no b핑 difference 00 1I1e extractive performance for

HFPO, it is r뼈파æ 10 se1ect 1he suitab1e solvent by αmsidering

1he several fiICtOrS meo뼈1ed 삶X>Ve. Moreover, it 해αJ!d be noted

that 1I1e heat φJty decreased as 1I1e increase in the feed π ... sure.

3.4. E뼈ct of reflux ratio on purity of HFPO

A ret1ux ratio 생 m표 of 1he ""'y important 야g뼈ng 뼈rsmeters

If 1I1e ret1ux ratio is 1따ge， the 벼ameter of a disti1lation ∞，lumn

increases, 11않벼ng to a 벼ffic띠t control of homogeneous flows

of gas and liquid. Therefore, 1I1e reflux ratio 얘ould be design어

as small 잃 possib1e unti1 the target p따ity of HFPO can be

establishOO. Fignre 6 shows 1he calcu1ated HFPO purity as a

functlon of f10w mte of 1,I-dich10r0-1-f1uoroethane wi1l1 v，앙10US

ref1ux ratios. The optimum ref1ux ratio shou1d be detennined

10 obtain the target purity at 1I1e 10w f10w mte of 1I1e solveot

As a re뼈t， 1he ref1ux ratios of 2.5 뻐d5 따e insuf죄cient and

the ref1ux ratio of 15 is 100 1없ge 10 reach desirab1e 1eve1 of

HFPO purity. Therefore, the ref1ux ratio of 10 is detennined

10 be the op미미zed ref1ux. ratio. Moreover, the mole fraction of

HFPOinα-eased as the increase in the feed pressure, which is

in good agreerneot with the resu1ts sbown in F멍ure 4.

4. Conclusions

The extractive distillation process was su야essfu11y designOO

using a 50flware of Aspeo P1us inc1uding 1I1e normal disti11atioo

process for 1he recyc1e of solveot The optimum tmy 10cations

could be se1ected f，π 1I1e feOO mixtore and 1I1e solvent for 1I1e

extractive disti1lation co1umn 50 1I1at the target purity of HFPO

in the top product could be obtained. The reflux 쩌.tio was a1∞

determin혀 toaι，hieve the pl피tyofI표1J'0 at 1I1e top of 1I1e di-

8뻐ation column 이 considering the minimum flow rate of the

solvent In addition 10 1I1e operating condition, adequate type

of solvent was found 10 be 1 ， 1-이C비oro-l-fluoroethane so that

the heat duty cou1d be minintized. Those design factors can be

버rectiy a뼈iOO 10 1he rea1 sepamtioo of 1표1J'O from its mixtore

of 1표꺼P

References

1. Droboy, J. G., Tecboo10gy of F11lOro]뼈ymers， 2:며 ed., CRC

Press, Boca Raton (2008)

2. Lee, E. J., et a1., “'Anti-fing하print Fi1ms 뼈d E1ectrica1 뻐d

E1ectmuic Appamtus," U.S. P없'atent No. 20αm’， 150α’，346，392 A1

(2014).

3. Lee, S.-B., et a1., ‘'H"，엉f1uoropropy1ene Oxide Po1ymer Com­

positions 뼈d a Method of prep없ing Hexaf1uor띠πopy1ene

Oxide Po1ymer Uaing Hexaflunropr야>y1ene Olignmer," U.S

Patent No. 8916666 (2011).

4. htφ:11www2.dupont.comlf1uorointermediates/en _ US/assets/

dowu1o뼈s/k05132.pdf (accessed Ju1y 2017)

5. R뼈피ck， L. R., Synthctlcs, Minernl αls， and Bio-B뻐OOLu­

bricants: Cheruistry and Techno10gy, 2nd 00., CRC Press,

Boca Ratoo (2013)

6. Emery, M , et a1., ‘'fhe Deve1야mænt of New Mem1πanes for

Proton Exch뻐ge Membrsne Fue1 Cells,'’ ECS Transactions, 11(1), 3-14 (2007).

7. Wr6b1ewska, A., et a1., “Oxidatioo of Hexaf1uoropropy1ene

with Oxygen 10 Hexafluoropropy1ene Oxide," Org. Process

Res. Dev., 14(1), 낀'2-277 (2010)

8. Nak양a， H , et a1, ‘'MeIbOd for S얀lOIa!ing Hexafluor따opy1ene

Oxide from Hexafluoroπopy1ene，" U.S. Pateot No. 201200

06672 A1 (2012).

9. fi1eμ'1Ic:/users/minzaeo/0201ee/download잉1eizhigang-se1f-2007

1 0-1.1퍼f (accessed Ju1y 2017).

10. http ’ Ilko1metz.com/pdf/foo/extracti ve-disti11ation. pdf

(accessed Ju1y 201η