U.S. patent application number 14/891381 was filed with the patent office on 2016-03-17 for method for separating aromatic compounds contained in naphtha.
The applicant listed for this patent is LOTTE CHEMICAL CORPORATION. Invention is credited to Joung Mo CHO, Jin Hyung KIM, Wang Gyu KIM, Young Jong SEO.
Application Number | 20160075952 14/891381 |
Document ID | / |
Family ID | 51933764 |
Filed Date | 2016-03-17 |
United States Patent
Application |
20160075952 |
Kind Code |
A1 |
KIM; Jin Hyung ; et
al. |
March 17, 2016 |
METHOD FOR SEPARATING AROMATIC COMPOUNDS CONTAINED IN NAPHTHA
Abstract
The present invention relates to a method for separating
aromatic compounds contained in naphtha which includes an
extraction step of contacting specific ionic liquids and naphtha
and a step of separating the aromatic compounds from naphtha
contacted with the ionic liquids.
Inventors: |
KIM; Jin Hyung; (Daejeon,
KR) ; KIM; Wang Gyu; (Daejeon, KR) ; CHO;
Joung Mo; (Daejeon, KR) ; SEO; Young Jong;
(Daejeon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LOTTE CHEMICAL CORPORATION |
Seoul |
|
KR |
|
|
Family ID: |
51933764 |
Appl. No.: |
14/891381 |
Filed: |
May 20, 2014 |
PCT Filed: |
May 20, 2014 |
PCT NO: |
PCT/KR2014/004492 |
371 Date: |
November 16, 2015 |
Current U.S.
Class: |
208/326 |
Current CPC
Class: |
B01D 11/04 20130101;
C07C 7/10 20130101; C10G 21/20 20130101 |
International
Class: |
C10G 21/20 20060101
C10G021/20 |
Foreign Application Data
Date |
Code |
Application Number |
May 20, 2013 |
KR |
10-2013-0056619 |
Nov 15, 2013 |
KR |
10-2013-0139235 |
Apr 25, 2014 |
KR |
10-2014-0050151 |
Apr 25, 2014 |
KR |
10-2014-0050152 |
Claims
1. A method for separating aromatic compounds contained in naphtha
which comprises the steps of: contacting naphtha with ionic liquids
including one or more compounds selected from the group consisting
of a bis-imidazolium-based ionic solvent, a bis-piperidinium-based
ionic solvent, a bis-pyrrolidinium-based ionic solvent, a
bis-morpholinium-based ionic solvent, a bis-imidazolium-based salt
including an ether group, a bis-piperidinium-based salt including
an ether group, a bis-pyrrolidinium-based salt including an ether
group, and a bis-morpholinium-based salt including an ether group;
and separating aromatic compounds from the naphtha contacted with
the ionic liquids.
2. The method for separating aromatic compounds contained in the
naphtha of claim 1 wherein: the bis-imidazolium-based salt
including an ether group includes a cation in which two
imidazolium-based rings are linked via a functional group including
one or more ether groups having a total carbon number of 2 to 20,
and a halide-based anion having hydrophobicity; the
bis-piperidinium-based salt including an ether group includes a
cation in which two piperidinium-based rings are linked via a
functional group including one or more ether groups having a total
carbon number of 2 to 20, and a halide-based anion having
hydrophobicity; the bis-pyrrolidinium-based salt including an ether
group includes a cation in which two pyrrolidinium-based rings are
linked via a functional group including one or more ether groups
having a total carbon number of 2 to 20, and a halide-based anion
having hydrophobicity; and the bis-morpholinium-based salt
including an ether group includes a cation in which two
morpholinium-based rings are linked via a functional group
including one or more ether groups having a total carbon number of
2 to 20, and a halide-based anion having hydrophobicity.
3. The method for separating aromatic compounds contained in the
naphtha of claim 1 wherein the bis-imidazolium-based salt including
an ether group includes a compound represented by Formula 1 below,
the bis-piperidinium-based salt including an ether group includes a
compound represented by Formula 2 below, the
bis-pyrrolidinium-based salt including an ether group includes a
compound represented by Formula 3 below, and the
bis-morpholium-based salt including an ether group includes a
compound represented by Formula 4 below: ##STR00008## in the above
Formula 1, R.sub.1 and R.sub.1' may be the same as or different
from each other and are each independently a linear or branched
alkyl group having 1 to 10 carbon atoms, a linear or branched
alkenyl group having 2 to 10 carbon atoms, a linear or branched
alkoxy group having 1 to 10 carbon atoms, or a linear or branched
alkyl carboxyl group having 1 to 10 carbon atoms, R.sub.2,
R.sub.2', R.sub.3, R.sub.3', R.sub.4, and R.sub.4' may be the same
as or different from each other and are each independently
hydrogen, a linear or branched alkyl group having 1 to 10 carbon
atoms, a linear or branched alkenyl group having 2 to 10 carbon
atoms, a linear or branched alkoxy group having 1 to 10 carbon
atoms, or a linear or branched alkyl carboxyl group having 1 to 10
carbon atoms, Y is (CF.sub.3SO.sub.2).sub.2N.sup.-, BF.sub.4-, or
PF.sub.6.sup.-, and X is the following Formula 1a or Formula 1b:
R.sub.ak1--O--R.sub.ak2 .sub.n [Formula 1a] R.sub.ak1--O
.sub.n--R.sub.ak2-- [Formula 1b] in the Formula 1a or Formula 1b,
R.sub.ak1 and R.sub.ak2 are each independently a linear or branched
alkylene group having 1 to 10 carbon atoms, and n is an integer
from 1 to 5; ##STR00009## in the above Formula 2, R.sub.1 and
R.sub.1' may be the same as or different from each other and are
each independently a linear or branched alkyl group having 1 to 10
carbon atoms, a linear or branched alkenyl group having 2 to 10
carbon atoms, a linear or branched alkoxy group having 1 to 10
carbon atoms, or a linear or branched alkyl carboxyl group having 1
to 10 carbon atoms, R.sub.2, R.sub.2', R.sub.3, R.sub.3', R.sub.4,
R.sub.4', R.sub.5, R.sub.5', R.sub.6, and R.sub.6' may be the same
as or different from each other and are each independently
hydrogen, a linear or branched alkyl group having 1 to 10 carbon
atoms, a linear or branched alkenyl group having 2 to 10 carbon
atoms, a linear or branched alkoxy group having 1 to 10 carbon
atoms, or a linear or branched alkyl carboxyl group having 1 to 10
carbon atoms, Y is (CF.sub.3SO.sub.2).sub.2N.sup.-, BF.sub.4-, or
PF.sub.6.sup.-, and X is the following Formula 2a or Formula 2b:
R.sub.ak1--O--R.sub.ak2 .sub.n [Formula 2a] R.sub.ak1--O
.sub.n--R.sub.ak2-- [Formula 2b] in the above Formula 2a or Formula
2b, R.sub.ak1 and R.sub.ak2 are each independently a linear or
branched alkylene group having 1 to 10 carbon atoms, and n is an
integer from 1 to 5; ##STR00010## in the above Formula 3, R.sub.1
and R.sub.1' may be the same as or different from each other and
are each independently a linear or branched alkyl group having 1 to
10 carbon atoms, a linear or branched alkenyl group having 2 to 10
carbon atoms, a linear or branched alkoxy group having 1 to 10
carbon atoms, or a linear or branched alkyl carboxyl group having 1
to 10 carbon atoms, R.sub.2, R.sub.2', R.sub.3, R.sub.3', R.sub.4,
R.sub.4', R.sub.5, and R.sub.5' may be the same as or different
from each other and are each independently hydrogen, a linear or
branched alkyl group having 1 to 10 carbon atoms, a linear or
branched alkenyl group having 2 to 10 carbon atoms, a linear or
branched alkoxy group having 1 to 10 carbon atoms, or a linear or
branched alkyl carboxyl group having 1 to 10 carbon atoms, Y is
(CF.sub.3SO.sub.2).sub.2N.sup.-, BF.sub.4-, or PF.sub.6.sup.-, and
X is the following Formula 3a or Formula 3b:
R.sub.ak1--O--R.sub.ak2 .sub.n [Formula 3a] R.sub.ak1--O
.sub.n--R.sub.ak2-- [Formula 3b] in the above Formula 3a or Formula
3b, R.sub.ak1 and R.sub.ak2 are each independently a linear or
branched alkylene group having 1 to 10 carbon atoms, and n is an
integer from 1 to 5; ##STR00011## in the above Formula 4, R.sub.1
and R.sub.1' may be the same as or different from each other and
are each independently a linear or branched alkyl group having 1 to
10 carbon atoms, a linear or branched alkenyl group having 2 to 10
carbon atoms, a linear or branched alkoxy group having 1 to 10
carbon atoms, or a linear or branched alkyl carboxyl group having 1
to 10 carbon atoms, R.sub.2, R.sub.2', R.sub.3, R.sub.3', R.sub.4,
R.sub.4', R.sub.5, and R.sub.5' may be the same as or different
from each other and are each independently hydrogen, a linear or
branched alkyl group having 1 to 10 carbon atoms, a linear or
branched alkenyl group having 2 to 10 carbon atoms, a linear or
branched alkoxy group having 1 to 10 carbon atoms, or a linear or
branched alkyl carboxyl group having 1 to 10 carbon atoms, Y is
(CF.sub.3SO.sub.2).sub.2N.sup.-, BF.sub.4-, or PF.sub.6.sup.-, and
X is the following Formula 4a or Formula 4b:
R.sub.ak1--O--R.sub.ak2 .sub.n [Formula 4a] R.sub.ak1--O
.sub.n--R.sub.ak2-- [Formula 4b] in the above Formula 4a or Formula
4b, R.sub.ak1 and R.sub.ak2 are each independently a linear or
branched alkylene group having 1 to 10 carbon atoms, and n is an
integer from 1 to 5.
4. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the bis-imidazolium-based ionic solvent
includes one or more compounds selected from the group consisting
of
1,1'-(1,2-ethanediyl)bis(3-methylimidazolium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl)bis(3-ethylimidazolium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(2,4'-butenediyl)bis(3-butylimidazolium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl-2-one)bis(3-ethylimidazolium)bis(trifluoromet-
hane sulfonyl)imide,
1,1'-(1,4-butanediyl-2,3-dione)bis(3-butylimidazolium)bis(trifluoromethan-
esulfonyl)imide,
1,1'-(1,4-butanediyl-2-ol)bis(3-methylimidazolium)bis(trifluoro
methanesulfonyl)imide, and
1,1'-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,2-ethanediyl)bis(3-methylimidazolium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl)bis(3-ethylimidazolium)bis(tetrafluoroborate),
1,1'-(2,4-betenediyl)bis(3-butylimidazolium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2-one)bis(3-ethylimidazolium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-dione)bis(3-ethylimidazolium)bis(tetrafluorobora-
te),
1,1'-(1,4-butanediyl-2-ol)bis(3-ethylimidazolium)bis(tetrafluoroborat-
e), and
1,1'-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(tetrafluo-
roborate),
1,1'-(1,2-ethanediyl)bis(3-methylimidazolium)bis(hexafluorophos-
phate),
1,1'-(1,4-butanediyl)bis(3-ethylimidazolium)bis(hexafluorophosphat-
e),
1,1'-(2,4-butenediyl)bis(3-butyl-imidazolium)bis(hexafluorophosphate),
1,1'-(1,4-butanediyl-2-pyridyl)bis(3-ethylimidazolium)bis(hexamethylene
fluorophosphate),
1,1'-(1,4-butanediyl-2,3-dione)bis(3-butylimidazolium)bis(hexafluorophosp-
hate),
1,1'-(1,4-butanediyl-2-ol)bis(3-ethylimidazolium)bis(hexafluorophos-
phate), and
1,1'-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(hexafluorophosph-
ate).
5. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the bis-pyrrolidinium-based ionic
solvent includes one or more compounds selected from the group
consisting of
1,1'-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-butylpyrrolidinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(trifluorometha-
ne sulfonyl)imide,
1,1'-(2,3-butendiyl)bis(1-ethylpyrrolidinium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(triflu-
oromethane sulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl)bis(1-butylpyrrolidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate)-
,
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(tetrafluorobo-
rate),
1,1'-(2,3-butenediyl)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate-
),
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(tetrafluoro-
borate),
1,1'-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(hexafluorophosp-
hate),
1,1'-(4-butanediyl)bis(1-butylpyrrolidinium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(hexafluorophosph-
ate),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(hexafluor-
ophosphate),
1,1'-(2,3-butenediyl)bis(1-ethylpyrrolidinium)bis(hexafluorophosphate),
and
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(hexafluor-
ophosphate); the bis-morpholinium-based ionic so vent includes one
or more compounds selected from the group consisting of
1,1'-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-butylmorpholinium)bis(trifluoro methane
sulfonyl)imide,
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylmorpholinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylmorpholinium)bis(trifluoromethan-
e sulfonyl)imide,
1,1'-(2,3-butenediyl)bis(1-ethylmorpholinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(trifluoro
methane sulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl)bis(1-butylmorpholinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylmorpholinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylmorpholinium)bis(tetrafluorobora-
te),
1,1'-(2,3-butenediyl)bis(1-ethylmorpholinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(tetrafluorobor-
ate),
1,1'-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl)bis(1-butylmorpholinium)bis(hexafluorophosphate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethyl-morpholinium)bis(hexafluorophosphat-
e),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylmorpholinium)bis(hexafluoroph-
osphate),
1,1'-(2,3-butendiyl)bis(1-ethylmorpholinium)bis(hexafluorophosph-
ate), and
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(hexaf-
luorophosphate); and the bis-piperidinium-based ionic solvent
includes one or more compounds selected from the group consisting
of
1,1'-(1,4-butanediyl)bis(1-ethylpiperidinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-butylpiperidinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl-2-ol)bis(1-ethyl-piperidinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpiperidinium)bis(trifluoro
methane sulfonyl)imide,
1,1'-(2,3-butanediyl)bis(1-ethylpiperidinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(trifluorometha-
ne sulfonyl)imide,
1,1'-(4-butanediyl)bis(1-ethylpiperidinium)bis(tetrafluoroborate),
1,1'-(1,4-butandiyl)bis(1-butylpiperidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpiperidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethyl-piperidinium)bis(tetrafluorobor-
ate),
1,1'-(2,3-butenediyl)bis(1-ethylpiperidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(tetrafluorobor-
ate),
1,1'-(1,4-butanediyl)bis(1-ethylpiperidinium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl)bis(1-butylpiperidinium)bis(hexafluorophosphate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpiperidinium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpiperidinium)bis(hexafluoropho-
sphate),
1,1'-(2,3-butenediyl)bis(1-ethylpiperidinium)bis(hexafluorophosph-
ate), and
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(hexaf-
luorophosphate).
6. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the naphtha is used in an amount of
0.05 to 5% by volume compared to the ionic liquids.
7. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the step of contacting the ionic liquid
and naphtha is conducted at a temperature of 20.degree. C. to
100.degree. C.
8. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the step of contacting the ionic
liquids and naphtha is conducted for 1 min or more.
9. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the step of contacting the ionic
liquids and naphtha is conducted for 30 min to 10 h.
10. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the step of separating aromatic
compounds from naphtha contacted with the ionic liquids is
conducted at least once.
11. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the step of separating aromatic
compounds from naphtha contacted with the ionic liquids includes a
step for conducting the separation by a liquid-liquid extraction
method.
12. The method for separating aromatic compounds contained in the
naphtha of claim 1, which further comprises a step for separating a
raffinate obtained in the extraction step.
13. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the step of separating aromatic
compounds from naphtha contacted with the ionic liquids further
comprises a step of conducting deaeration at a temperature of 20 to
150.degree. C. and a pressure of 1 to 200 mmHg.
14. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the extraction step is performed in a
pulsed extraction column.
15. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the pulsation is introduced at a
velocity of 10 m/s to 60 m/s in the pulsed extraction column.
16. The method for separating aromatic compounds contained in the
naphtha of claim 1, which further comprises the steps of
introducing the extraction solvent into the upper end of the pulsed
extraction column, and introducing the naphtha into the lower end
of the pulsed extraction column.
17. The method for separating aromatic compounds contained in the
naphtha of claim 1, wherein the step of separating aromatic
compounds from naphtha contacted with the ionic liquids is a step
of conducting the separation by a liquid-liquid extraction method.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for separating
aromatic compounds contained in naphtha, and more particularly to
an environmentally friendly and economical separation method that
is capable of removing aromatic compounds from naphtha through a
simple process with high efficiency while eliminating the need for
multi-stage processes or various processing devices.
BACKGROUND ART
[0002] In naphtha generated during oil refining, aliphatic
compounds such as butane, pentane, cyclopentane, heptane, and
octane as well as main aromatic compounds such as benzene, toluene,
mixed xylene, and ethylbenzene are contained in an amount of about
4% to 15%.
[0003] If the main aromatic compounds contained in naphtha are
selectively removed, the yield of ethylene and propylene is
increased due to an increase in furnace cracking efficiency upon
thermal cracking of naphtha and the amount of fuel used during the
cracking decreases, and thereby a reduction in the amount of carbon
dioxide by up to 10% is achieved.
[0004] Specifically, in the case of removing about 90% of the
aromatic compounds from naphtha, it is known that the yield of
ethylene and propylene increases by about 3%.
[0005] In addition, there is an advantage of increasing the life of
coils by reducing the occurrence of short-circuits in the naphtha
cracker coil.
[0006] As a typical process for separating aromatic compounds
contained in naphtha, the sulfolane process of UOP LLC is
known.
[0007] The sulfolane process is a process of separating aromatic
compounds from C6.about.C8 Heart Cut (HTPG) derived from a
hydrogenation process by using an extraction distillation method.
Since the sulfolane has a higher boiling point than the C8 aromatic
compound, it is possible to easily separate the aromatic compound
from the extraction solvent. Therefore, the sulfolane is used as an
extraction solvent.
[0008] However, such a sulfone process has problems in terms of
energy, cost, and environmental aspects as described below.
[0009] First, in terms of energy, the sulfolane process involves a
total of two distillation columns, and refers to a process which
includes separating benzene from a first distillation column
(extraction process), transferring the fraction having a high
boiling point to a second distillation column (stripper) and
separating toluene again through the distillation, wherein toluene
is separated from the first distillation column at the maximum
concentration and then re-mixed and transferred to the second
distillation column, and thus toluene leads to the remixing
phenomenon which is repeated in the first and second distillation
columns. Thus, there is a problem that energy is inefficiently
consumed.
[0010] Also, in terms of cost, because the sulfolane process is a
large-scale process involving an extraction distillation column and
a plurality of devices for recycling a stripper and an extraction
solvent, the operation costs involved in the use of a distillation
device for separation and a heat exchanger among various devices
are high.
[0011] Further, in terms of the environmental aspects, sulfolane is
a typical polar material. Sulfolane has advantages in that it is
stable to heat and hydrolysis and has a high boiling point, but
sulfolane also has disadvantages in that it has low selectivity for
extracting aromatic compounds as well as aliphatic compounds and
that a small amount of sulfolane is mixed with the aliphatic
compounds, thus causing loss of the solvent.
[0012] Further, sulfolane starts to be decomposed at 200.degree. C.
When exceeding 260.degree. C., it shows a high decomposition
rate.
[0013] This means that the decomposition of the solvent occurs when
a high temperature is applied for the regeneration of the solvent
in the regeneration column.
[0014] Furthermore, the presence of oxygen in the process
accelerates the decomposition of sulfolane. At this time, a
generated acid gas results in corrosion in the process.
[0015] In addition to the sulforane process, some methods for
separating aromatic compounds from naphtha are known.
[0016] As an example, U.S. Pat. No. 5,849,981 relates to adsorptive
separation, and more particularly discloses a method for
selectively separating aromatic components using an adsorbent
obtained by substituting one or more barium or potassium ions in
zeolite.
[0017] However, in the case of using such a method, there are
disadvantages in that the absorption capacity is limited, and a
high temperature and high vacuum are required during
desorption.
[0018] Furthermore, U.S. Pat. No. 4,914,064 discloses a method for
separation with a membrane, and more particularly, a method for
separating aromatic components and aliphatic components using an
anisotropic elastomeric polymer membrane prepared from a
polyurea/urethane copolymer.
[0019] However, such a liquid membrane method has disadvantages in
that the method for manufacturing the particular membrane used is
difficult and the cost is expensive.
[0020] Furthermore, this method has disadvantages in that some
membrane components are lost by an introduced gas and it is
difficult to maintain separation efficiency for a long period of
time, thus lowering efficiency.
[0021] In addition, a method for removing aromatic compounds from
naphtha by double separation extraction using a halide-based ionic
liquid as an extraction solvent of the liquid-liquid extraction
method is known.
[0022] However, there is a high possibility that, when having F--,
Cl--, Br--, or I-- at the anion part of the ionic liquid, these are
reacted with water used or partially contained during the process
and thereby it is highly likely to be decomposed into hydrofluoric
acid, hydrochloric acid, hydrobromic acid, hydrochloric acid, or
hydroiodic acid, which cause toxicity and corrosion. Further, there
is a problem that, due to relatively low electronegativity, the
interaction with aromatic compounds is weak, thus decreasing the
extraction efficiency of the main aromatic compounds.
PRIOR ART DOCUMENT
Patent Document
[0023] (Patent Document 1) U.S. Pat. No. 5,849,981
[0024] (Patent Document 2) U.S. Pat. No. 4,914,064
DISCLOSURE OF INVENTION
Technical Problem
[0025] It is an object of the present invention to provide an
environmentally friendly and economical separation method that is
capable of removing aromatic compounds from naphtha through a
simple process with high efficiency while eliminating the need for
multi-stage processes or various processing devices.
Technical Solution to Problem
[0026] In order to achieve these objects, and other objects which
will become apparent from the description, the present invention
provides a method for separating aromatic compounds contained in
naphtha which includes the steps of: contacting naphtha with ionic
liquids including one or more compounds selected from the group
consisting of a triethylene glycol, a bis-imidazolium based ionic
solvent, a bis-piperidinium-based ionic solvent, a
bis-pyrrolidinium-based ionic solvent, a bis-morpholinium-based
ionic solvent, a bis-imidazolium-based salt including an ether
group, a bis-piperidinium-based salt including an ether group, a
bis-pyrrolidinium-based salt including an ether group, and a
bis-morpholinium-based salt including an ether group; and
separating aromatic compounds from the naphtha contacted with the
ionic liquids.
[0027] Below, the method for separating aromatic compounds
contained in naphtha in accordance with specific embodiments of the
present invention will be described in more detail.
[0028] The term "alkylene" as used herein refers to a divalent
functional group derived from an alkane.
[0029] According to one embodiment of the present invention, a
method for separating aromatic compounds contained in naphtha which
includes the steps of: contacting naphtha with ionic liquids
including one or more compounds selected from the group consisting
of a triethylene glycol, a bis-imidazolium-based ionic solvent, a
bis-piperidinium-based ionic solvent, a bis-pyrrolidinium-based
ionic solvent, a bis-morpholinium-based ionic solvent, a
bis-imidazolium-based salt including an ether group, a
bis-piperidinium-based salt including an ether group, a
bis-pyrrolidinium-based salt including an ether group, and a
bis-morpholinium-based salt including an ether group; and
separating aromatic compounds from the naphtha contacted with the
ionic liquids can be provided.
[0030] The present inventors found through numerous experiments
that, when conducting the step of contacting naphtha with the ionic
liquids including the above-described particular compounds and the
step of separating aromatic compounds from the naphtha contacted
with the ionic liquids, the aromatic compounds can be removed from
naphtha through a simple process with high efficiency while
eliminating the need for multi-stage processes or processing
devices. The present invention has been completed on the basis of
such a finding.
[0031] In the process of using the ionic liquids including the
above-described particular compounds, components having toxicity or
causing corrosion are not generated, thus allowing a more
environmentally friendly process to be implemented.
[0032] Further, the aromatic compounds can be more effectively
removed from naphtha with high efficiency even when conducting only
the extraction step using the ionic liquids including the
above-described particular compounds. Therefore, the need can be
eliminated for complicated processes such as a multi-step
extraction process or a purification process or installation of
various devices, thus allowing a more economical process to be
implemented.
[0033] The ionic liquid (IL) is a liquid composed of ions as
defined in P. Wasserschied, T. Welton, Ionic Liquid in Synthesis,
2nd Ed, Wiley-VCH, 2008. In a broad sense, ionic liquid refers to a
molten salt present as a liquid at a relatively low temperature of
less than 100.degree. C.
[0034] Since the ionic liquid can be designed to have cations and
anions according to its intended application, a range of
application such as a catalyst, a reaction solvent, a separation
medium, or an electrolyte solvent is broad.
[0035] In particular, the ionic liquid (IL) may be non-volatile and
thermally stable as well as having high solubility and selectivity
for metals, organic matter, and organic metals.
[0036] In the method for separating aromatic compounds contained in
naphtha in accordance with the above embodiment of the invention,
the ionic liquids including one or more compounds selected from the
group consisting of a triethylene glycol, a bis-imidazolium-based
ionic solvent, a bis-piperidinium-based ionic solvent, a
bis-pyrrolidinium-based ionic solvent, a bis-morpholinium-based
ionic solvent, a bis-imidazolium-based salt including an ether
group, a bis-piperidinium-based salt including an ether group, a
bis-pyrrolidinium-based salt including an ether group, and a
bis-morpholinium-based salt including an ether group can be
used.
[0037] Specifically, the bis-imidazolium-based salt including an
ether group can include a cation in which two imidazolium-based
rings are linked via a functional group including one or more ether
groups having a total carbon number of 2 to 20, and a halide-based
anion having hydrophobicity. The bis-piperidinium-based salt
including an ether group can include a cation in which two
piperidinium-based rings are linked via a functional group
including one or more ether groups having a total carbon number of
2 to 20, and a halide-based anion having hydrophobicity. The
bis-pyrrolidinium-based salt including an ether group can include a
cation in which two pyrrolidinium-based rings are linked via a
functional group including one or more ether groups having a total
carbon number of 2 to 20, and a halide-based anion having
hydrophobicity. The bis-morpholinium-based salt including an ether
group can include a cation in which two morpholinium-based rings
are linked via a functional group including one or more ether
groups having a total carbon number of 2 to 20, and a halide-based
anion having hydrophobicity.
[0038] The total carbon number of the ether group refers to the
total number of carbon atoms except for the oxygen atom contained
in the ether group.
[0039] Specific examples of the functional group including one or
more ether groups having a total carbon atom number of 2 to 20 may
include a functional group to which 1 to 10 ether groups having a
total carbon number of 2 to 20 are linked.
[0040] The bis-imidazolium-based salt including an ether group, the
bis-piperidinium-based salt including an ether group, the
bis-pyrrolidinium-based salt including an ether group, and the
bis-morpholinium-based salt including an ether group, which are
included in the above ionic liquids, include two parts having a
monovalent cation and two parts having an anion, respectively. The
parts of interaction (hydrogen bond, .pi.-interaction, etc.) with
aromatic compounds contained in naphtha increase so the aromatic
compounds contained in naphtha can be more efficiently
extracted.
[0041] The bis-imidazolium-based salt including an ether group, the
bis-piperidinium-based salt including an ether group, the
bis-pyrrolidinium-based salt including an ether group, or the
bis-morpholinium-based salt including an ether group are configured
such that two imidazolium-based rings, piperidinium-based rings,
pyrrolidinium-based rings, or morpholinium-based rings are linked
via a functional group including one or more ether groups having a
total carbon number of 2 to 20, wherein the imidazolium-based
rings, the piperidinium-based rings, the pyrrolidinium-based rings,
or the morpholinium-based rings have aromatic structures.
Therefore, the above-described salts can easily form
.pi.-interaction with the aromatic compounds contained in naphtha,
thus more increasing the extraction efficiency.
[0042] Further, since the bis-imidazolium-based salt including an
ether group, the bis-piperidinium-based salt including an ether
group, the bis-pyrrolidinium-based salt including an ether group,
or the bis-morpholinium-based salt including an ether group have an
ether group, these salts can easily form a hydrogen bond with the
aromatic compounds contained in naphta, thus increasing the
extraction efficiency.
[0043] Further, the bis-imidazolium-based salt including an ether
group, the bis-piperidinium-based salt including an ether group,
the bis-pyrrolidinium-based salt including an ether group, or the
bis-morpholinium-based salt including an ether group may include an
ether group and thereby include a halide-based anion having
hydrophobicity, for example, (CF.sub.3SO.sub.2).sub.2N.sup.-,
BF.sub.4-, or PF.sub.6.sup.-.
[0044] However, since such halide-based anions having
hydrophobicity have greater electronegativity as compared with
halogen ions (F--, Cl--, Br--, or I--) and two may be present in
the above-described salt compounds, interactions such as hydrogen
bonds with the aromatic compounds contained in naphtha can be
maximized, thereby more efficiently extracting the aromatic
compounds contained in naphtha.
[0045] Since the bis-imidazolium-based salt including an ether
group, the bis-piperidinium-based salt including an ether group,
the bis-pyrrolidinium-based salt including an ether group, or the
bis-morpholinium-based salt including an ether group do not have
substantial viscosity, the mass transfer of aromatic components
(transfer from naphtha to ionic liquids) can be activated, thereby
increasing the extraction efficiency of the aromatic
components.
[0046] Also, since four kinds of the salt compounds as mentioned
above have a very stable structure, the extracting performance of
the aromatic compounds contained in naphtha can be maintained for a
long period of time.
[0047] Further, the ionic liquids used in the separation method
according to the above embodiment of the invention show
hydrophobicity and so have almost no affinity to water. Therefore,
unlike conventional ionic liquids including F--, Cl--, Br--, or
I-based anions, since these ionic liquids do not react with water
at all, harmful substances such as a hydrohalogenic acid (for
example, hydrofluoronic acid) are not discharged.
[0048] Furthermore, since the ionic liquids used in the separation
method according to the above embodiment of the invention have no
own vapor pressure due to a boiling point (bp) of more than about
400.degree. C., there is no risk that the solvent is lost upon its
re-use, in contrast with conventional organic solvent extraction
agents. Further, these ionic liquids do not require a separate
process so are cost-effective. In addition, components that cause
environmental pollution are not discharged so it is possible to
design an environmentally friendly process.
[0049] The bis-imidazolium-based salt including an ether group may
include a compound represented by the following Formula 1.
##STR00001##
[0050] In the above Formula 1, R.sub.1 and R.sub.1' may be the same
as or different from each other and are each independently a linear
or branched alkyl group having 1 to 10 carbon atoms, a linear or
branched alkenyl group having 2 to 10 carbon atoms, a linear or
branched alkoxy group having 1 to 10 carbon atoms, or a linear or
branched alkyl carboxyl group having 1 to 10 carbon atoms, and
R.sub.2, R.sub.2', R.sub.3, R.sub.3', R.sub.4, and R.sub.4' may be
the same as or different from each other and are each independently
hydrogen, a linear or branched alkyl group having 1 to 10 carbon
atoms, a linear or branched alkenyl group having 2 to 10 carbon
atoms, a linear or branched alkoxy group having 1 to 10 carbon
atoms, or a linear or branched alkyl carboxyl group having 1 to 10
carbon atoms.
[0051] Further, in the above Formula 1, Y is
(CF.sub.3SO.sub.2).sub.2N.sup.-, BF.sub.4-, or PF.sub.6.sup.-, and
X is the following Formula 1a or Formula 1b.
R.sub.ak1--O--R.sub.ak2 .sub.n [Formula 1a]
R.sub.ak1--O .sub.n--R.sub.ak2-- [Formula 1b]
[0052] In the above Formula 1 a or Formula 1 b, R.sub.ak1 and
R.sub.ak2 are each independently a linear or branched alkylene
group having 1 to 10 carbon atoms, and n is an integer from 1 to
5.
[0053] The bis-piperidinium-based salt including an ether group may
include a compound represented by the following Formula 2.
##STR00002##
[0054] In the above Formula 2, R.sub.1 and R.sub.1' may be the same
as or different from each other and are each independently a linear
or branched alkyl group having 1 to 10 carbon atoms, a linear or
branched alkenyl group having 2 to 10 carbon atoms, a linear or
branched alkoxy group having 1 to 10 carbon atoms, or a linear or
branched alkyl carboxyl group having 1 to 10 carbon atoms, and
R.sub.2, R.sub.2', R.sub.3, R.sub.3', R.sub.4, R.sub.4', R.sub.5,
R.sub.5', R.sub.6, and R.sub.6' may be the same as or different
from each other and are each independently hydrogen, a linear or
branched alkyl group having 1 to 10 carbon atoms, a linear or
branched alkenyl group having 2 to 10 carbon atoms, a linear or
branched alkoxy group having 1 to 10 carbon atoms, or a linear or
branched alkyl carboxyl group having 1 to 10 carbon atoms.
[0055] Further, in the above Formula 2, Y is
(CF.sub.3SO.sub.2).sub.2N.sup.-, BF.sub.4-, or PF.sub.6.sup.-, and
X is the following Formula 2a or Formula 2b.
R.sub.ak1--O--R.sub.ak2 .sub.n [Formula 2]
R.sub.ak1--O .sub.n--R.sub.ak2-- ]Formula 2b]
[0056] In the above Formula 2a or Formula 2b. R.sub.ak1 and
R.sub.ak2 are each independently a linear or branched alkylene
group having 1 to 10 carbon atoms, and n is an integer from 1 to
5.
[0057] The bis-pyrrolidinium-based salt including an ether group
may include a compound represented by the following Formula 3.
##STR00003##
[0058] In the above Formula 3, R.sub.1 and R.sub.1' may be the same
as or different from each other and are each independently a linear
or branched alkyl group having 1 to 10 carbon atoms, a linear or
branched alkenyl group having 2 to 10 carbon atoms, a linear or
branched alkoxy group having 1 to 10 carbon atoms, or a linear or
branched alkyl carboxyl group having 1 to 10 carbon atoms, and
R.sub.2, R.sub.2', R.sub.3, R.sub.3', R.sub.4, R.sub.4', R.sub.5,
and R.sub.5' may be the same as or different from each other and
are each independently hydrogen, a linear or branched alkyl group
having 1 to 10 carbon atoms, a linear or branched alkenyl group
having 2 to 10 carbon atoms, a linear or branched alkoxy group
having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl
group having 1 to 10 carbon atoms.
[0059] Further, in the above Formula 3, Y is
(CF.sub.3SO.sub.2).sub.2N.sup.-, BF.sub.4-, or PF.sub.6.sup.-, and
X is the following Formula 3a or Formula 3b.
R.sub.ak1--O--R.sub.ak2 .sub.n [Formula 3a]
R.sub.ak1--O .sub.n--R.sub.ak2-- [Formula 3b]
[0060] In the above Formula 3a or Formula 3, R.sub.ak1 and
R.sub.ak2 are each independently a linear or branched alkylene
group having 1 to 10 carbon atoms, and n is an integer from 1 to
5.
[0061] The bis-morpholium-based salt including an ether group may
include a compound represented by the following Formula 4.
##STR00004##
[0062] In the above Formula 4, R.sub.1 and R.sub.1' may be the same
as or different from each other and are each independently a linear
or branched alkyl group having 1 to 10 carbon atoms, a linear or
branched alkenyl group having 2 to 10 carbon atoms, a linear or
branched alkoxy group having 1 to 10 carbon atoms, or a linear or
branched alkyl carboxyl group having 1 to 10 carbon atoms, and
R.sub.2, R.sub.2', R.sub.3, R.sub.3', R.sub.4, R.sub.4', R.sub.5,
and R.sub.5' may be the same as or different from each other and
are each independently hydrogen, a linear or branched alkyl group
having 1 to 10 carbon atoms, a linear or branched alkenyl group
having 2 to 10 carbon atoms, a linear or branched alkoxy group
having 1 to 10 carbon atoms, or a linear or branched alkyl carboxyl
group having 1 to 10 carbon atoms.
[0063] Further, in the above Formula 4, Y is
(CF.sub.3SO.sub.2).sub.2N.sup.-, BF.sub.4-, or PF.sub.6.sup.-, and
X is the following Formula 4a or Formula 4b.
R.sub.ak1--O--R.sub.ak2 .sub.n [Formula 4a]
R.sub.ak1--O .sub.n--R.sub.ak2-- [Formula 4b]
[0064] In the above Formula 4a or Formula 4b, R.sub.ak1 and
R.sub.ak2 are each independently a linear or branched alkylene
group having 1 to 10 carbon atoms, and n is an integer from 1 to
5.
[0065] Specific examples of the compounds contained in the above
ionic liquids may include compounds represented by the following
Formulas 11 to 29.
##STR00005## ##STR00006## ##STR00007##
[0066] The bis-imidazolium-based salt including an ether group may
include one or more compounds selected from the group consisting of
[2-(1-ethylimidazolium-3-yl-ethoxy)-ethyl]-1-ethylimidazolium
bis(trifluoromethanesulfonyl)imide,
[2-(1-butylimidazolium-3-yl-ethoxy)-ethyl]-1-butylimidazolium
bis(trifluoromethanesulfonyl)imide,
[4-(1-ethylimidazolium-3-yl-butoxy)-butyl]-1-ethylimidazolium
bis(trifluoromethanesulfonyl)imide,
{2-[2-(1-ethylimidazolium-3-yl-ethoxy)-ethoxy]-ethyl}-1-ethylimidazolium
bis(trifluoromethanesulfonyl)imide,
(2-{2-[2-(1-ethylimidazolium-3-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethyli-
midazolium bis(trifluoromethanesulfonyl)imide,
[2-(1-ethylimidazolium-3-yl-ethoxy)ethyl]-1-ethylimidazolium
bis(tetrafluoroborate),
[2-(1-butylimidazolium-3-yl-ethoxy)ethyl]-1-butylimidazolium
bis(tetrafluoroborate),
[4-(1-ethylimidazolium-3-yl-butoxy)-butyl]-1-ethylimidazolium
bis(tetrafluoroborate),
{2-[2-(1-ethylimidazolium-3-yl-ethoxy)-ethoxy]-ethyl}-1-ethylimidazolium
bis(tetrafluoroborate),
(2-{2-[2-(1-ethylimidazolium-3-yl-ethoxy)-ethoxy]ethoxyl-ethyl}-1-ethylim-
idazolium bis(tetrafluoroborate),
[2-(1-ethylimidazolium-3-yl-ethoxy)ethyl]-1-ethylimidazolium
bis(hexafluorophosphate),
[2-(1-butylimidazolium-3-yl-ethoxy)ethyl]-1-butylimidazolium
bis(hexafluorophosphate),
[4-(1-ethylimidazolium-3-yl-butoxy)-butyl]-1-ethylimidazolium
bis(hexafluorophosphate),
{2-[2-(1-ethylimidazolium-3-yl-ethoxy)-ethoxy]-ethyl}-1-ethylimidazolium
bis(hexafluorophosphate), and
(2-{2-[2-(1-ethylimidazolium-3-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethyli-
midazolium bis(hexafluorophosphate).
[0067] The bis-piperidinium-based salt including an ether group may
include one or more compounds selected from the group consisting of
[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethyl]-ethylpiperidinium
bis(trifluoromethanesulfonyl)imide,
[2-(1-butylpiperidinium-1-yl-ethoxy)-ethyl]-1-butylpiperidinium
bis(trifluoromethanesulfonyl)imide,
[4-(1-ethylpiperidinium-1-yl-butoxy)-butyl]-1-ethylpiperidinium
bis(trifluoromethane sulfonyl)imide,
{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]-ethyl}-1-ethylpiperidiniu-
m bis(trifluoromethane sulfonyl)imide,
(2-{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethyl-
piperidinium bis(trifluoro methanesulfonyl)imide,
[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethyl]-1-ethylpiperidinium
bis(tetrafluoroborate),
[2-(1-butylpiperidinium-1-yl-ethoxy)-ethyl]-1-butylpiperidinium
bis(tetrafluoroborate),
[4-(1-ethylpiperidinium-1-yl-butoxy)-butyl]-1-ethylpiperidinium
bis(tetrafluoroborate),
{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]-ethyl}-1-ethylpiperidiniu-
m bis(tetrafluoroborate),
(2-{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethyl-
piperidinium bis(tetrafluoroborate),
[2-(1-ethylpiperidinium-1-yl-ethoxy)ethyl]-1-ethylpiperidinium
bis(hexafluorophosphate),
[2-(1-butylpiperidinium-1-yl-ethoxy)ethyl]-1-butylpiperidinium
bis(hexafluorophosphate),
[4-(1-ethylpiperidinium-1-yl-butoxy)-butyl]-1-ethylpiperidinium
bis(hexafluorophosphate),
{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]-ethyl}-1-ethylpiperidiniu-
m bis(hexafluorophosphate), and
(2-{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethyl-
piperidium bis(hexafluorophosphate).
[0068] The bis-pyrrolidinium-based salt including an ether group
may include one or more compounds selected from the group
consisting of
[2-(1-ethylpyrrolidinium-1-yl-ethoxy)ethyl]-1-ethylpyrrolidinium
bis(trifluoromethanesulfonyl)imide,
[2-(1-butylpyrrolidinium-1-yl-ethoxy)-ethyl]-1-butylpyrrolidinium
bis(trifluoromethanesulfonyl)imide,
[4-(1-ethylpyrrolidinium-1-yl-butoxy)-butyl]-1-ethyl]-1-ethylpyrrolidiniu-
m bis(trifluoromethanesulfonyl)imide,
{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy-ethoxy]-ethyl}-1-ethylpyrrolidini-
um bis(trifluoromethanesulfonyl)imide,
(2-{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethy-
lpyrrolidinium bis(trifluoromethanesulfonyl)imide,
[2-(1-ethylpyridinium-1-yl-ethoxy)-ethyl]-1-ethylpyrrolidinium
bis(tetrafluoroborate),
[2-(1-butylpyrrolidinium-1-yl-ethoxy)-ethyl]-1-butylpyrrolidinium
bis(tetrafluoroborate),
[4-(1-ethylpyrrolidinium-1-yl-butoxy)-butyl]-1-ethylpyrrolidinium
bis(tetrafluoroborate),
{2-[2-(1-ethylpyrrolidinium-1-ethoxy)-ethoxy]-ethyl}-1-ethyl-pyrrolidiniu-
m bis(tetrafluoroborate),
(2-{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethy-
lpyrrolidinium bis(tetrafluoroborate),
[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethyl]-1-ethylpyrrolidinium
bis(hexafluorophosphate),
[2-(1-butylpyrrolidinium-1-yl-ethoxy)-ethyl]-1-butylpyrrolidinium
bis(hexafluorophosphate),
[4-(1-ethylpyrrolidinium-1-yl-butoxy)-butyl]-1-ethylpyrrolidinium-bis(hex-
afluorophosphate),
{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]-ethyl}-1-ethylpyrrolidin-
ium bis(hexafluorophosphate), and
(2-{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethy-
lpyrrolidinium.
[0069] The bis-morpholinium-based salt including an ether group may
include one or more compounds selected from the group consisting of
[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethyl]-4-ethylmorpholinium
bis(trifluoromethane sulfonyl)imide,
[2-(4-butymorpholinium-4-yl-ethoxy)-ethyl]-4-butylmorpholinium
bis(trifluoromethanesulfonyl)imide,
[4-(4-ethylmorpholinium-4-yl-butoxy)-butyl]-4-ethylmorpholinium
bis(trifluoromethanesulfonyl)imide,
{2-[2-(4-ethylpyrrolidinium-4-yl-ethoxy)-ethoxy]-ethyl}-4-ethylmorpholini-
um bis(trifluoromethane sulfonyl)imide,
(2-{2-[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxyl}-ethyl)-4-ethylmorphol-
inium bis(trifluoromethane sulfonyl)imide,
[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethyl]-4-ethylmorpholinium
bis(tetrafluoroborate),
[2-(4-butylmorpholinium-4-yl-ethoxy)-ethyl]-4-butylmorpholinium
bis(tetrafluoroborate),
[4-(4-ethylmorpholinium-4-yl-butoxy)-butyl]-4-ethylmorpholinium
bis(tetrafluoroborate),
{2-[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxy]-ethyl}-4-ethylmorpholiniu-
m(tetrafluoroborate),
(2-{2-[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxy]ethoxy}-ethyl)-4-ethylm-
orpholinium bis(tetrafluoroborate),
[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethyl]-4-ethylmorpholinium
bis(hexafluorophosphate),
[2-(4-butylmorpholinium-4-yl-ethoxy)-ethyl]-4-butylmorpholinium
bis(hexafluorophosphate),
[4-(4-ethylmorpholinium-4-yl-butoxy)-butyl]-4-ethylmorpholinium
bis(hexafluorophosphate),
{2-[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxy]-ethyl}-4-ethylmorpholiniu-
m(hexafluorophosphate), and
(2-{2-[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-4-ethyl-
morpholinium bis(hexafluorophosphate).
[0070] On the other hand, the bis-imidazolium-based ionic solvent
that may be included in the ionic liquids may include one or more
selected from the group consisting of
1,1'-(1,2-ethanediyl)bis(3-methylimidazolium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl)bis(3-ethylimidazolium)bis(trifluoromethanesu-
lfonyl)imide,
1,1'-(2,4'-butenediyl)bis(3-butylimidazolium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl-2-one)bis(3-ethylimidazolium)bis(trifluoromet-
hanesulfonyl)imide,
1,1'-(1,4-butanediyl-2,3-dione)bis(3-butylimidazolium)bis(trifluoromethan-
esulfonyl)imide,
1,1'-(1,4-butanediyl-2-ol)bis(3-methylimidazolium)bis(trifluoromethanesul-
fonyl)imide,
1,1'-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(trifluoromethane-
sulfonyl)imide,
1,1'-(1,2-ethanediyl)bis(3-methylimidazolium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl)bis(3-ethylimidazolium)bis(tetrafluoroborate),
1,1'-(2,4-betenediyl)bis(3-butylimidazolium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2-one)bis(3-ethylimidazolium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-dione)bis(3-ethylimidazolium)bis(tetrafluorobora-
te),
1,1'-(1,4-butanediyl-2-ol)bis(3-ethylimidazolium)bis(tetrafluoroborat-
e),
1,1'-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(tetrafluorobo-
rate),
1,1'-(1,2-ethanediyl)bis(3-methylimidazolium)bis(hexafluorophosphat-
e),
1,1'-(1,4-butanediyl)bis(3-ethylimidazolium)bis(hexafluorophosphate),
1,1'-(2,4-butenediyl)bis(3-butylimidazolium)bis(hexafluorophosphate),
1,1'-(1,4-butanediyl-2-one)bis(3-ethylimidazolium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl-2,3-dione)bis(3-butylimidazolium)bis(hexafluoropho-
sphate),
1,1'-(1,4-butanediyl-2-ol)bis(3-ethylimidazolium)bis(hexafluoroph-
osphate), and
1,1'-(1,4-butanediyl-2,3-diol)bis(3-ethylimidazolium)bis(hexafluorophosph-
ate).
[0071] Further, the bis-pyrrolidinium-based ionic solvent that may
be included in the ionic liquids may include one or more selected
from the group consisting of
1,1'-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(trifluoromethane
sulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-butylpyrrolidinium)bis(trifluoromethanesulfony-
l)imide,
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(trifluorom-
ethanesulfonyl)imide,
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(trifluorometha-
nesulfonyl)imide,
1,1'-(2,3-butendiyl)bis(1-ethylpyrrolidinium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(triflu-
oromethanesulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl)bis(1-butylpyrrolidinium)bis(tetrafluoroldorate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate)-
,
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(tetrafluorobo-
rate),
1,1'-(2,3-butenediyl)bis(1-ethylpyrrolidinium)bis(tetrafluoroborate-
),
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(tetrafluoro-
borate),
1,1'-(1,4-butanediyl)bis(1-ethylpyrrolidinium)bis(hexafluorophosp-
hate),
1,1'-(4-butanediyl)bis(1-butylpyrrolidinium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(hexafluorophosph-
ate),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpyrrolidinium)bis(hexafluor-
ophosphate),
1,1'-(2,3-butenediyl)bis(1-ethylpyrrolidinium)bis(hexafluorophosphate),
and
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpyrrolidinium)bis(hexafluor-
ophosphate).
[0072] Further, the bis-morpholinium-based ionic solvent may
include one or more selected from the group consisting of
1,1'-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl)bis(1-butylmorpholinium)bis(trifluoromethanes-
ulfonyl)imide,
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylmorpholinium)bis(trifluoromethanesul-
fonyl)imide,
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylmorpholinium)bis(trifluoromethan-
esulfonyl)imide,
1,1'-(2,3-butenediyl)bis(1-ethylmorpholinium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(trifluo-
romethanesulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl)bis(1-butylmorpholinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylmorpholinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylmorpholinium)bis(tetrafluorobora-
te),
1,1'-(2,3-butenediyl)bis(1-ethylmorpholinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(tetrafluorobor-
ate),
1,1'-(1,4-butanediyl)bis(1-ethylmorpholinium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl)bis(1-butylmorpholinium)bis(hexafluorophosphate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethyl-morpholinium)bis(hexafluorophosphat-
e),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethyl-morpholinium)bis(hexafluorop-
hosphate),
1,1'-(2,3-butendiyl)bis(1-ethyl-morpholinium)bis(hexafluorophos-
phate), and
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylmorpholinium)bis(hexafluorophos-
phate).
[0073] Further, the bis-piperidinium-based ionic solvent may
include one or more selected from the group consisting of
1,1'-(1,4-butanediyl)bis(1-ethylpiperidinium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl)bis(1-butylpiperidinium)bis(trifluoromethanes-
ulfonyl)imide,
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpiperidinium)bis(trifluoromethanesul-
fonyl)imide,
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpiperidinium)bis(trifluoromethan-
esulfonyl)imide,
1,1'-(2,3-butanediyl)bis(1-ethylpiperidinium)bis(trifluoromethanesulfonyl-
)imide,
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(trifluo-
romethanesulfonyl)imide,
1,1'-(1,4-butanediyl)bis(1-ethylpiperidinium)bis(tetrafluoroborate),
1,1'-(1,4-butandiyl)bis(1-butylpiperidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpiperidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpiperidinium)bis(tetrafluorobora-
te),
1,1'-(2,3-butenediyl)bis(1-ethylpiperidinium)bis(tetrafluoroborate),
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(tetrafluorobor-
ate),
1,1'-(1,4-butanediyl)bis(1-ethylpiperidinium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl)bis(1-butylpiperidinium)bis(hexafluorophosphate),
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpiperidinium)bis(hexafluorophosphate-
),
1,1'-(1,4-butanediyl-2,3-diol)bis(1-ethylpiperidinium)bis(hexafluoropho-
sphate),
1,1'-(2,3-butenediyl)bis(1-ethylpiperidinium)bis(hexafluorophosph-
ate), and
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(hexaf-
luorophosphate).
[0074] On the other hand, for naphtha, as a subject from which to
extract and separate the aromatic compounds, conventional naphtha
known in the art can be used without limitation.
[0075] For example, the naphtha may contain 4% to 15% by weight of
aromatic compounds, and in particular it may contain 4% to 15% by
weight of aromatic compounds such as benzene, toluene, mixed
xylene, and ethylbenzene.
[0076] As an example of the naphtha, aliphatic hydrocarbon
compounds, for example, aliphatic hydrocarbon compounds including
compounds such as butane (about 2.3 wt %), pentane (about 30.1 wt
%), hexane (about 31.8 wt %), heptane (about 8.7 wt %), octane
(about 8.1 wt %), nonane (about 2.0 wt %) and/or decane (about 7.0
wt %), and aromatic compounds, for example, aromatic compounds
including compounds such as benzene (about 1.8 wt %), toluene
(about 3.0 wt %), mixed xylene (about 3.2 wt %), and/or ethyl
benzene (about 2.0 wt %) can be included.
[0077] On the other hand, in the method for separating aromatic
compounds contained in naphtha in accordance with the above
embodiment of the invention, the naphtha can be used in an amount
of 0.05 to 5% by volume, or 0.1 to 3% by volume compared to the
ionic liquids.
[0078] When the naphtha is used in an amount of less than 0.05% by
volume compared to the ionic liquids, the efficiency or
productivity and economy of the method for separation of aromatic
compounds contained in naphtha in accordance with the above one
embodiment of the invention cannot be sufficiently secured, and for
the recovery of aromatic compounds, it may be necessary to add
additional process devices or process steps to the separation
method in accordance with the above one embodiment.
[0079] If the used amount of the naphtha exceeds 5% by volume
compared to the ionic liquids, the extraction efficiency of the
aromatic compounds can be lowered. In order to sufficiently
separate the aromatic compounds from naphtha, it may be necessary
to add the multi-step processes or additional process devices.
[0080] The step of contacting the ionic liquids and naphtha may be
conducted at a temperature of 20.degree. C. to 100.degree. C. or a
temperature of 25.degree. C. to 80.degree. C.
[0081] If the step of contacting the ionic liquids and naphtha is
conducted at a temperature of less than 20.degree. C., there are
problems in that the viscosity of the ionic liquids is increased,
the dispersion is lowered, and the mass transfer performance is
decreased.
[0082] Further, if the step of contacting the ionic liquids and
naphtha is conducted at a temperature of greater than 100.degree.
C., there may be a problem in that naphtha is vaporized and contact
with an ionic liquid is not smoothly made so the extraction
performance is reduced. In addition, due to energy consumption,
production costs may be increased.
[0083] The time required for conducting the step of contacting the
ionic liquid and naphtha is not particularly limited, but the
contacting can be conducted for more than 1 min or more than 30 min
so that the aromatic compounds can be in sufficient contact with
the ionic liquids. Specifically, the contact can be conducted for 1
min to 20 h or for 30 min to 10 h.
[0084] The steps for separating the aromatic compounds from naphtha
contacted with the ionic liquids can be conducted at least once,
for example once to four times.
[0085] The steps for separating the aromatic compounds from naphtha
contacted with the ionic liquids can include a step for separation
by a liquid-liquid extraction method.
[0086] The liquid-liquid extraction method can use conventionally
known methods and devices. It is possible to select an organic
solvent that is used in consideration of the polarity and the like
of the substance.
[0087] The method for separation of aromatic compounds contained in
naphtha according to the above embodiment of the invention may
further include a step for separating the raffinate obtained in the
extraction step.
[0088] The raffinate refers to a component that is not extracted or
adsorbed by the solvent extraction or molecular sieve extraction.
In the extraction step, the raffinate refers to a residue in which
aromatic compound components are separated from naphtha.
[0089] The method for separation of aromatic compounds contained in
naphtha according to the above embodiment of the invention may
further include a deaeration step for separating aromatic compounds
from the ionic liquids.
[0090] The raffinate and the ionic liquids are introduced into the
evaporator and then the deaeration step can be conducted.
[0091] The deaeration refers to an operation of removing gas
dissolved in the liquid. In the present specification, the
deaeration refers to vaporizing the aromatic compounds present in
the ionic liquid and removing them.
[0092] The deaeration can be conducted at a temperature of
20.degree. C. to 150.degree. C. or 50.degree. C. to 120.degree.
C.
[0093] If the temperature during said deaeration is too low, the
deaeration performance is lowered so a problem that the extraction
efficiency is decreased when reusing the ionic liquids may
occur.
[0094] Further, if the temperature during said deaeration is too
high, a problem that variations in the ionic liquid and energy
consumption increase may occur.
[0095] The deaeration can be conducted under the pressure of 1 mmHg
to 200 mmHg or 50 mmHg to 100 mmHg.
[0096] If the pressure during said deaeration is too low, a problem
that energy consumption increases may occur.
[0097] Furthermore, if the pressure during said deaeration is too
high, a problem that deaeration performance is lowered and the
extraction efficiency is lowered when reusing the inonic liquids
may occur.
[0098] That is, the step of separating aromatic compounds from
naphtha contacted with the ionic liquids may further include a step
of conducting the deaeration at a temperature of 20 to 150.degree.
C. and a pressure of 1 to 200 mmHg.
[0099] The time required for conducting the deaeration is not
particularly limited, but in order to sufficiently ensure the
deaeration efficiency, the deaeration can be conducted for 5 min or
more, specifically for 10 min to 300 min, or 30 min to 120 min.
[0100] The step of separating an aromatic compound from naphtha
contacted with the ionic liquids may further include a step of
contacting the ioinic liquid after the separation step with naphtha
and reusing it.
[0101] For example, after the deaeration step, the raffinate and
the aromatic compounds separated from the ionic liquids are
discharged to a passage of the upper end of the evaporator, and the
ionic liquid in which the aromatic compound has been separated is
discharged to a passage of the lower end of the evaporator and
again introduced into an ionic liquid inlet passage of the
extraction column and reused.
[0102] In other words, the ionic liquids in which the aromatic
compounds have been separated through an deaeration step can be
reused without loss.
[0103] In the method for separating aromatic compounds contained in
naphtha in accordance with the above one embodiment of the
invention, the extraction step of contacting the ionic liquids and
naphtha can be conducted in a pulsed extraction column.
[0104] The pulsed extraction column refers to an extraction column
that imparts a pulsation to the continuation phase of the
liquid-liquid countercurrent extraction column. By imparting a
pulsation to the liquid, the pulsed extraction column utilizes a
phenomenon in which a phase having a small volume ratio among two
liquid phases is dispersed in the form of a drop within the other
continuation phase.
[0105] Since the separation method of the above one embodiment of
the invention utilizes a pulsed extraction column, the
dispersibility increases and a mass transfer performance is
remarkably improved, thereby increasing the efficiency for
extracting aromatic compounds from naphtha.
[0106] In the pulsed extraction column, the pulse generating motor
at the upper end is operated at a velocity of 10 m/s to 60 m/s or
20 m/s to 50 m/s, so a double tube pulsation-type column conducts a
vertical reciprocating motion.
[0107] If the velocity of the pulsation generating motor is too
slow and is less than 10 m/s, problems in that the vertical
reciprocating motion of the pulsed extraction column is decreased
and thus the dispersion and the mass transfer performance are
reduced may occur, thus lowering the extraction efficiency of the
aromatic compounds.
[0108] Further, if the velocity of the pulsation generating motor
is too fast and is greater than 60 m/s, problems in that the
functionability is lowered due to the abrasion of the device and
production costs cab increase due to consumption of energy may
occur.
[0109] If the extraction step is conducted in the pulsed extraction
column, the method for separating aromatic compounds contained in
naphtha according to the above embodiment of the invention may
further include a step of introducing the ionic liquids into the
upper end of the pulsed extraction column, and a step of
introducing the naphtha into the lower end of the pulsed extraction
column.
[0110] The configuration of the pulsed extraction column used in
the above extraction step may include conventionally known methods
and conventionally known elements or device members except for the
above-described configuration.
[0111] In the method for separating aromatic compounds according to
the above one embodiment of the invention, conventional methods or
devices which are known to be capable of being used for the
separation of naphtha except for the above-described configuration
can be used without limitation.
Advantageous Effects of the Invention
[0112] According to the present invention, an environmentally
friendly and economical separation method that is capable of
removing aromatic compounds from naphtha through a simple process
with a high efficiency while eliminating the need for multi-stage
processes or various processing devices.
[0113] In the method for separating aromatic compounds contained in
naphtha, components having toxicity or causing corrosion are not
generated, thus allowing a more environmentally friendly process to
be implemented. Further, even if only the extraction step using the
particular ionic liquids is conducted, it is possible to more
effectively remove the aromatic compounds from naphtha at high
efficiency. Therefore, the need can be eliminated for complicated
processes such as a multi-step extraction process or a purification
process or installation of various devices, thus allowing a more
economical process to be implemented.
BRIEF DESCRIPTION OF DRAWING
[0114] FIG. 1 is a schematic view illustrating the method for
separating aromatic compounds from naphtha using the pulsed
extraction column.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0115] The present invention will be described in more detail by
way of the examples below. However, these examples are intended
only to illustrate the present invention, and the contents of the
present invention are not intended to be limited by the
examples.
PREPARATION EXAMPLE
Preparation of the Ionic Liquids
1. Preparation Example 1
Preparation of
[2-(1-ethylimidazolium-3-yl-ethoxy)ethyl]-1-ethylimidazolium
bis(trifluoromethanesulfonyl)imide
[0116] In a 250 ml two-necked flask equipped with a reflux device,
50 g of
[2-(1-ethylimidazolium-3-yl-ethoxy)ethyl]-1-ethylimidazolium
dibromide [424.17 g/mol] and 78 g of
bis(trifluoromethanesulfonyl)imide lithium salt [287.09 g/mol] (2.3
eq.) were placed with water as the solvent and then stirred at room
temperature for about 2 h. The reaction product was worked up to
remove unreacted materials and then dried in vacuum at 60.degree.
C. to give a
[2-(1-ethylimidazolium-3-yl-ethoxy)-ethyl]-1-ethylimidazolium
bis(trifluoromethane sulfonyl)imide compound with a yield of
98%.
2. Preparation Example 2
Preparation of [4-(1-ethyl
piperidinium-3-yl-butoxy)-butyl]-1-ethylpiperidinium
bis(trimethanesulfonyl)imide
[0117] In a 250 ml two-necked flask equipped with a reflux device,
50 g of
[4-(1-ethylpiperidinium-1-yl-butoxy)-butyl]-1-ethylpiperidinium
dibromide [514.42 g/mol] and 64 g of bis(trifluoromethane
sulfonyl)imide lithium salt [287.09g/mol] (2.3 eq.) were placed
with water as the solvent and then stirred at room temperature for
about 2 h. The reaction product was worked-up to remove unreacted
materials and then dried in vacuum at 60.degree. C. to give a
[4-(1-ethylpiperidinium-1-yl-butoxy)-butyl]-1-ethylpiperidinium
bis(trifluoromethane sulfonyl)imide compound with a yield of
98%.
3. Preparation Example 2
Preparation of
{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]-ethyl}-1-ethylpyrrolidin-
ium bis(tetrafluoroborate)
[0118] In a 250 ml two-necked flask equipped with a reflux device,
50 g of
{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]-ethyl}-1-ethylpyrrolidin-
ium dibromide [474.31 g/mol] and 23 g of tetrafluoroborate lithium
salt [93.75 g/mol] (2.3 eq.) were placed with water as the solvent
and then stirred at room temperature for about 2 h. The reaction
product was worked-up to remove unreacted materials and then dried
in vacuum at 60.degree. C. to give
{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]-ethyl}-1-ethyl-pyrrolidi-
nium bis(tetrafluoroborate) with a yield of 98%.
4. Preparation Example 4
Preparation of
(2-{2-(2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxy]-1-ethyl)-4-ethylmorpho-
linium(hexafluorophosphate)
[0119] In a 250 ml two-necked flask equipped with the reflux
device, 50 g of
(2-{2-(2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxy]-ethyl)-4-ethylmorph-
olinium dibromide [550.37 g/mol] and 32 g of hexafluorophosphate
lithium salt [151.91 g/mol] (2.3 eq.) were placed with water as the
solvent and then stirred at room temperature for about 2 h. The
reaction product was worked-up to remove unreacted materials and
then dried in vacuum at 60.degree. C. to give a
(2-{2-(2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxy]-1-ethyl)-4-ethylmorpho-
linium(hexafluorophosphate) compound with a yield of 98%.
EXAMPLES AND COMPARATIVE EXAMPLES
Separation of Aromatic Compounds from Naphtha
Example 1
[0120] 5 g of a naphtha sample and 10 g of
[2-(1-ethylimidazolium-3-yl-ethoxy)-ethyl]-1-ethylimidazolium
bis(trifluoromethanesulfonyl)imide were mixed, stirred at
25.degree. C. for 1 h, and then stabilized for 30 min to separate
an upper-layer liquid and a lower-layer liquid.
[0121] Then, the separated upper-layer liquid was analyzed using
gas chromatography (Young Lin equipment, model #: YL6100), equipped
with HD and FFAP columns. In the lower-layer liquid, the extraction
rate of the main aromatic compounds was analyzed using Bruker
Nuclear Magnetic Resonance (400 MHz; 52 MM, Coil No: 944067A).
[0122] After extraction, the removal rate of the main aromatic
compounds contained in
[2-(1-ethylimidazolium-3-yl-ethoxy)-ethyl]-1-ethylimidazolium
bis(trifluoromethanesulfonyl) was as shown in Table 1 below.
Examples 2 to 20
[0123] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 1, except
that the kinds of the bis-imidazolium-based ionic liquid including
an ether group and the bis-biimidazolium-based ionic liquid
including an ether group, represented by the above Formulae 1 to 4,
were changed and used as shown in Table 1 below.
[0124] After extraction, the extraction removal rates of the main
aromatic compounds contained in the ionic liquid extraction solvent
were as shown in Table 1 below.
Comparative Example
[0125] 5 g of naphtha sample and 10 g of sulfolane were mixed,
stirred at 25.degree. C. for 1 h, and then stabilized for 30 min to
separate an upper-layer liquid and a lower-layer liquid.
[0126] Then, the separated upper-layer liquid was analyzed using
gas chromatography (Young Lin equipment, model #: YL6100), equipped
with FID and FFAP columns. In the lower-layer liquid, the
extraction rate of the main aromatic compounds was analyzed using
Bruker Nuclear Magnetic Resonance (400 MHz/52 MM, Coil No:
944067A).
[0127] The removal rates of the main aromatic compounds contained
in the main aromatic compounds were shown in Table 1 below.
TABLE-US-00001 TABLE 1 Extraction rate (%) Mixed Ethyl Class Kinds
of ionic liquids (Formulae 1 to 3) Benzene Toluene xylene benzene
Ex. 1 2-(1-ethylimidazolium-3-yl-ethoxy)ethyl]-1- 97 97 95 96
ethylimidazolium bis(trifluoromethane sulfonyl)imide Ex. 2
[2-(1-butylimidazolium-3-yl-ethoxy)-ethyl] 95 95 92 93
butylimidazolium bis(trifluoromethane sulfonyl)imide Ex. 3
[4-(1-ethylimidazolium-3-yl-butoxy)-butyl]-1-ethyl 96 95 94 95
imidazolium bis(trifluoro methane sulfonyl)imide Ex. 4
{2-[2-(1-ethylimidazolium-3-yl-ethoxy)-ethoxy]- 99 98 96 97
ethyl}-1-ethylimidazolium bis(trifluoromethane sulfonyl)imide Ex. 5
(2-{2-[2-(1-ethylimidazolium-3-yl-ethoxy)-ethoxy]- 99 98 98 98
ethoxy}-ethyl)-1-ethylimidazolium bis(trifluoromethane
sulfonyl)imide Ex. 6 [2-(1-ethylpiperidinium-1-yl-ethoxy)ethyl]-1-
96 95 93 94 ethylpiperidinium bis(trifluoromethanesulfonyl)imide
Ex. 7 [2-(1-butylpiperidinium-1-yl-ethoxy)ethyl]-1-butyl 94 93 91
92 piperidinium bis(trifluoromethanesulfonyl) imide Ex. 8
4-(1-ethylpiperidinium-1-yl-butoxy)-butyl]-1-ethyl 95 94 93 94
piperidinium bis(trifluoromethanesulfonyl) imide Ex. 9
{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]- 99 98 96 96
ethyl}-1-ethylpiperidinium bis(trifluoromethane sulfonyl)imide Ex.
10 (2-{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]- 99 98 97 98
ethoxy}-ethyl)-1-ethylpiperidinium
bis(trifluoromethanesulfonyl)imide Ex. 11
[2-(1-ethylpyrrolidinium-1-yl-ethoxy)ethyl]-1- 96 95 93 93
ethylpyrrolidinium-bis(trifluoromethane sulfonyl)imide Ex. 12
[2-(1-butylpyrrolidinium-1-yl-ethoxy)-ethyl]-1- 94 92 91 92
butylpyrrolidinium-bis(trifluoromethane sulfonyl)imide Ex. 13
[4-(1-ethylpyrrolidinium-1-yl-butoxy)-butyl]-1-ethyl- 95 94 92 93
pyrrolidinium bis(trifluoromethane sulfonyl)imide Ex. 14
{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]- 98 97 95 96
ethyl}-1-ethylpyrrolidinium bis(trifluoromethane sulfonyl)imide Ex.
15 (2-{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]- 99 98 97 97
ethoxy}-ethyl)-1-ethylpyrrolidinium bis(trifluoromethane
sulfonyl)imide Ex. 16 [2-(4-ethylmorpholinium
4-yl-ethoxy)-ethyl]-4- 98 98 96 97 ethylmorpholinium
bis(trifluoromethane sulfonyl)imide Ex. 17
[2-(4-butylmorpholinium-4-yl-ethoxy)-ethyl]-4- 96 96 94 95
butylmorpholinium bis(trifluoromethane sulfonyl)imide Ex. 18
[4-(4-ethylmorpholinium-4-yl-butoxy)-butyl]-4-ethyl- 97 97 96 96
morpholinium bis(trifluoromethanesulfonyl) imide Ex. 19
{2-[2-(4-ethylmorpholinium 4-yl-ethoxy)-ethoxy]- 99 98 96 97
ethyl}-4-ethylmorpholinium bis(trifluoromethane sulfonyl)imide Ex.
20 (2-{2-[2-(4-ethylmorpholinium-4-yl-ethoxy)-ethoxy]- 99 99 97 98
ethoxy}-ethyl)-4-ethylmorpholinium
bis(trifluoromethanesulfonyl)imide Com. Ex. Sulfolane 28 14 12
15
[0128] As shown in Table 1 above, it was confirmed that, in the
case of using the ionic liquids in Examples 1 to 20 as an
extraction solvent, the interaction with the aromatic compounds was
active, so relatively, electronegativity can more effectively
extract the aromatic compounds from naphtha.
Examples 20 to 26
[0129] The aromatic compounds were extracted from naphtha by
conducting a process in the same manner as Example 1, except that
two kinds of ionic liquids different from each other were used
instead of using only one kind of the ionic liquid as the
extraction solvent.
[0130] After extraction, the extraction removal rates of the main
aromatic compounds contained in the ionic liquid-based extraction
solvent were as shown in Table 2.
TABLE-US-00002 TABLE 2 Extraction rate (%) Kind of ionic liquids
(Formula 1)* Mixed Ethyl Class A B Benzene Toluene xylene benzene
Ex. 1 [2-(1-ethylimidazolium-3-yl-ethoxy)-ethyl]-1-ethyl- 97 97 95
96 imidazolium bis(trifluoromethanesulfonyl)imide Ex. 20
[2-(1-ethyl imidazolium-3- [2-(1-ethyl piperidinium- 97 97 96 96
yl-ethoxy)-ethyl]-1- 1-yl-ethoxy) ethyl]-1- ethylimidazolium ethyl
piperidinium bis(trifluoromethanesulfonyl)imide
bis(trifluoromethanesulfonyl)imide Ex. 21 [2-(1-butylimidazolium-3-
[4-(1-ethylpyridinium-1- 96 95 94 94
yl-ethoxy)-ethyl]-1-butylimidazolium yl-butoxy)-butyl]-1-
bis(trifluoromethanesulfonyl)imide ethylpyrrolidinium
bis(trifluoromethanesulfonyl) imide Ex. 22
{2-[2-(1-ethylimidazolium- [2-(4-ethyl- 98 97 96 97
3-yl-ethoxy)-ethoxy]-ethyl}- morpholinium-4-yl- 1-ethyl-imidazolium
ethoxy)-ethyl]-4- bis(trifluoromethanesulfonyl)imide
ethylmorpholinium bis(trifluoromethanesulfonyl) imide Ex. 23
[2-(1-butyl-piperidinium-1- [4-(4-ethyl- 97 97 95 96 yl-ethoxy)
ethyl]-1-butyl morpholinium-4-yl- piperidinium butoxy)-butyl]-4-
bis(trifluoromethanesulfonyl)imide ethylmorpholinium
bis(trifluoromethanesulfonyl)imide Ex. 24 {2-[2-(1-
[2-(4-butylmorpholinium- 97 96 95 95 ethylpyrrolidinium-1-yl-
4-yl-ethoxy)ethyl]-4- ethoxy)-ethoxy]-ethyl}-1- butylmorpholinium
ethylpyrrolidinium- bis(trifluoromethanesulfonyl)
bis(trifluoromethanesulfonyl) imide imide Ex.
[2-(1-ethylpyrrolidinium-1- [4-(1-ethylpiperidinium- 96 95 93 4 25
yl-ethoxy)-ethyl]-1- 1-yl-butoxy)-butyl]-1- ethylpyrrolidiniun-
ethylpiperidinium bis(trifluoromethanesulfonyl)
bis(trifluoromethanesulfonyl)imide imide Ex. 26 (2-{2-[2-(1-
(2-{2-[2-(1- 99 99 98 98 ethylpyperidinium-1-yl-
ethyimidazolium-3-yl- ethoxy)-ethoxy]-ethoxy}-
ethoxy)-ethoxy]-ethoxy}- ethyl)-1-ethylpiperidinium ethyl)-1-
bis(trifluoromethanesulfonyl)imide ethylimidazolium
bis(trifluoromethanesulfonyl)imide *Used ratio of the ionic liquids
(A:B) = 1:1
[0131] As shown in Table 2 above, it was confirmed that in the case
of using two kinds of the ionic liquids, the extraction effects
were exhibited at a level equivalent to or superior to that of
Example 1 using one kind of the ionic liquid.
Examples 27 to 33
[0132] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 1, except
that
[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethyl]-1-ethylpyrrolidinium
bis(trifluoromethanesulfonyl)imide was used as the extraction
solvent, and the used amounts of the naphtha samples were changed
as shown in Table 3 below.
[0133] After the extraction, the extraction removal rates of the
main aromatic compounds contained in the ionic liquid-based
extraction solvent were as shown in Table 3 below.
TABLE-US-00003 TABLE 3 Naphtha Extraction rate (%) sample Ben-
Tolu- Mixed Ethyl Class (g)* zene ene xylene benzene Example 27 0.5
100 100 100 100 Example 28 1 100 100 100 100 Example 11 5 96 95 93
93 Example 29 10 89 87 85 86 Example 30 20 82 78 75 76 Example 31
30 72 66 63 65 Example 32 40 61 54 50 52 Example 33 50 50 47 44 45
*Amount of naphtha sample applied based on 10 g of the inoic liquid
extraction solvent
Examples 34 to 36
[0134] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 1, except
that
[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethyl]-1-ethylpyrrolidinium
bis(trifluoromethanesulfonyl)imide was used as the extraction
solvent, the throughput of naphtha applied was changed to 5 times
by weight with respect to the bis-biimidazolium-based ionic liquid
including an ether group, and the extraction was conducted by
changing the extraction steps.
[0135] After the extraction, the extraction removal rates of the
main aromatic compounds contained in naphtha were as shown in Table
4 below.
TABLE-US-00004 TABLE 4 Extraction rate (%) Extraction Ben- Tolu-
Mixed Ethyl Class step* zene ene xylene benzene Example 33 1 50 47
44 45 Example 34 2 71 69 67 68 Example 35 3 91 89 88 88 Example 36
4 100 100 100 100
[0136] As shown in Table 4 above, it was confirmed that if the
amount of naphtha was increased compared to the ionic liquids, the
extraction efficiency was secured up to 100% by repeating the
extraction steps of contacting the ionic liquid and the naphtha
twice to four times.
Examples 37 to 44
[0137] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 1, except
that
[2-(4-ethylmorpholinium-4-yl-ethoxy)ethyl]-4-ethyl-morpholinium
bis(trifluoromethanesulfonyl)imide was used as the extraction
solvent, and the extraction temperature was changed as shown in
Table 5 below.
[0138] After extraction, the extraction removal rates of the main
aromatic compounds contained in naphtha were as shown in Table 5
below.
TABLE-US-00005 TABLE 5 Extraction Extraction rate (%) temperature
Ben- Tolu- Mixed Ethyl Class (.degree. C.) zene ene xylene benzene
xample 16 25 98 98 96 97 Example 37 30 96 96 95 95 Example 38 40 94
94 92 93 Example 39 50 91 90 88 89 Example 40 60 89 88 86 87
Example 41 70 87 86 84 85 Example 42 80 85 84 82 83 Example 43 90
82 81 80 80 Example 44 100 80 79 76 77
[0139] As shown in Table 5 above, it could be confirmed that, even
if the extraction temperature was changed from 25.degree. C. to
100.degree. C., in Examples 37 to 44, the extraction rates of the
aromatic compounds in naphtha were nearly 80%, resulting in
excellent extraction efficiency.
Examples 45-51
[0140] The aromatic compounds in naphtha were extracted by
conducting a process in the same condition and manner as in Example
1, except that
{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethoxy]-ethyl}-1-ethyl-piperidini-
um bis(trifluoromethanesulfonyl)imide was used as the extraction
solvent. After the extraction, hydrocarbons of the main aromatic
compounds contained in the ionic liquid extraction solvent were
deaerated under reduced pressure.
[0141] At this time, the deaeration rate according to the
deaeration conditions of the temperature, pressure, and time were
as shown in Table 6 below.
TABLE-US-00006 TABLE 6 Deaeration condition of hydrocarbons
Deaeration rate (%) Temperature Pressure Time Mixed Ethyl Class
(.degree. C.) (mmHg) (h) enzene Toluene xylene benzene Example 45
20 70 2 88 90 93 92 Example 46 50 20 1 100 100 100 100 Example 47
70 70 2 100 100 100 100 Example 48 80 150 1 83 85 89 87 Example 49
100 50 1 100 100 100 100 Example 50 120 100 1 90 94 97 96 Example
51 150 30 0.5 100 100 100 100
[0142] As shown in Table 6 above, it could be confirmed that ether
group-containing bis-imidazolium-based ionic extraction solvents
and bis-biimidazolium-based ionic liquids could be reused in the
extraction process without loss under the deaeration condition.
Examples 52 to 56 and Comparative Example 2
[0143] In the separation of the aromatic compounds in naphtha
mixture using the pulsed extraction column, the extraction solvent
was introduced in the upper end of the pulsed extraction column 3
via the extraction solvent inlet passage 1 at a velocity of 5 mL
per min under a room temperature condition and at the same time
naphtha was introduced in the lower end of the pulsed extraction
column 3 via the naphtha inlet passage 2 at a velocity of 1 mL per
min, and thereby the liquid-liquid extraction separation was
conducted at a pulsation velocity of 50 m/s for 3 h within the
pulsed extraction column.
[0144] After the liquid-liquid extraction separation, the raffinate
of the upper-layer (naphtha mixture in which the aromatics have
been removed) was discharged to the passage 4 of the upper end of
the pulsed extraction column. The extraction rate of the aromatic
compounds was analyzed using Gas Chromatography (Young Lin
equipment, model #: YL6100), equipped with FID and FFAP
columns.
[0145] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds contained in each
extraction solvent was as shown in Table 11 below.
TABLE-US-00007 TABLE 11 Extration rate (%) Ionic liquid Ben- Tolu-
Mixed Ethyl Class [Extraction solvent] zene ene xylene Benzene
Comp. Sulfolane 28 14 12 15 Ex. 2 Ex. 52 [2-(1-ethylimidazolium- 96
95 93 95 3-yl-ethoxy)ethyl]-1- ethylimidazolium bis(tri-
fluoromethane sulfonyl)imide Ex. 53 {2-[2-(1-ethyl 99 98 97 97
imidazolium-3-yl-ethoxy)- ethoxy]ethylimidazolium
bis(trifluoromethane sulfonyl)imide Ex. 54 [2-(1-butylpiperidinium-
97 96 95 96 1-yl-ethoxy)-ethyl]-1-butyl piperidinium bis(trifluoro-
methanesulfonyl)imide Ex. 55 [4-(4-ethylmorpholinium 98 97 96 96
4-yl-butoxy)-butyl]-4- ethylmorpholinium bis(tri- fluoromethane
sulfonyl)imide Ex. 56 (2-{2-[2-(1-ehtyl- 99 98 96 97
pyrrolidinium-1-yl-ethoxy)- ethoxy]-ethoxy}-
ethyl)-1-ethylpyrrolidinium bis(trifluoromethane sulfonyl)imide
[0146] As shown in Table 11 above, in the case of Examples 52 to 56
using a specific ionic liquid having high electronegativity, it
appears that an interaction between the ionic liquid and the
aromatic compounds contained in naphtha actively occurred, and
thereby it was confirmed that high extraction efficiency was
obtained.
[0147] In contrast, it could be confirmed that Comparative Example
2 using sulfolane had a low extraction effect as compared with the
examples.
Example 57 to 64
[0148] The aromatic compounds were extracted from naphtha mixture
by conducting a process in the same manner as in Example 52, except
that
{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethyl]-1-ethylpiperidinium
bis(trifluoromethanesulfonyl)imide was used as the extraction
solvent and the used amount (introduced amount) of the naphtha
mixture was changed as shown in Table 12 below.
[0149] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds was as shown in Table 12
below.
TABLE-US-00008 TABLE 12 Naphtha Extraction rate (%) mixture Ben-
Tolu- Mixed Ethyl Class (mL/min)* zene ene xylene benzene Example
57 0.25 100 100 100 100 Example 58 0.5 100 100 100 100 Example 59 1
97 96 94 95 Example 60 5 88 85 83 84 Example 61 10 80 76 72 75
Example 62 15 70 64 61 63 Example 63 20 59 51 48 50 Example 64 25
49 45 42 43 *Amount of naphtha mixture applied based on 5 mL/min of
the extraction solvent includng the ionic liquids
[0150] As shown in Table 12 above, it was confirmed that Examples
57 to 64 could, even in the case of contacting an excess amount of
the naphtha mixture compared to the ionic liquids (extraction
solvent), secure higher extraction efficiency as compared to
Comparative Example 1.
[0151] In particular, as has been confirmed from the results of
Examples 6 to 9, when using the naphtha in an amount of 0.05% to 5%
by volume or 0.1% to 3% by volume compared to the ionic liquids, a
higher extraction efficiency was secured.
Examples 65 to 67
[0152] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 52, except
that
{2-[2-(1-ethylpiperidinium-1-yl-ethoxy)-ethyl]-1-ethylpiperidinium
bis(trifluoromethanesulfonyl)imide was used as the extraction
solvent, the used amount (introduced amount) of naphtha compared to
the bis-biimidazolium-based ionic liquid including an ether group
was changed to 5% by volume, and the extraction was conducted by
changing the number of times for conducting the separation with the
liquid-liquid extraction method.
[0153] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds was as shown in Table 13
below.
TABLE-US-00009 TABLE 13 Number of times Extraction rate (%) for
conducting the Ben- Tolu- Mixed Ethyl Class separation steps zene
ene xylene benzene Example 65 1 49 45 42 43 Example 66 2 70 66 63
64 Example 67 3 90 87 86 86 Example 68 4 100 100 100 100
[0154] As shown in Table 13 above, it was confirmed that, when
increasing the amount of naphtha compared to the ionic liquids, the
extraction effect was secured up to 100% as the extraction steps of
contacting the ionic liquid and the naphtha were repeated two times
to four times.
Examples 69 to 73
[0155] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 52, except
that [4-(4-ethylmorpholium-4-yl-butoxy)-butyl]-4-ethylmorpholium
bis(trifluoromethanesulfonyl)imide was used as the extraction
solvent, and the velocity of the pulsation generation motor in the
pulsed extraction column was changed as shown in Table 14
below.
[0156] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds was as shown in Table 14
below.
TABLE-US-00010 TABLE 14 Extraction rate (%) Velocity Ben- Tolu-
Mixed Ethyl Class (m/s) zene ene xylene benzene Example 69 10 89 88
87 88 Example 70 20 91 90 89 89 Example 71 30 93 92 90 91 Example
72 40 95 95 93 93 Example 55 50 98 97 96 96 Example 73 60 99 98 96
97
[0157] As shown in Table 14 above, when using the ionic liquids as
the extraction solvent, even if the pulsation injection velocity
within the pulsed extraction column was changed from 10 m/s to 60
m/s, the extraction rate of the aromatic compounds in naphtha was
87% or more, which confirmed that the extraction efficiency was
excellent.
Examples 74 to 81
[0158] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 52, except
that
(2-{2-[2-(1-ethylpyrrolidinium-1-yl-ethoxy)-ethoxy]-ethoxy}-ethyl)-1-ethy-
lpyrrolidinium bis(trifluoromethanesulfonyl)imide was used as the
extraction solvent, and the extraction temperature was changed as
shown in Table 15 below.
[0159] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds was as shown in Table 15
below.
TABLE-US-00011 TABLE 15 Extraction Extraction rate (%) temperature
Ben- Tolu- Mixed Ethyl Class (.degree. C.) zene ene xylene benzene
Example 56 25 99 98 96 97 Example 74 30 97 96 95 95 Example 75 40
95 94 92 93 Example 76 50 92 91 89 89 Example 77 60 90 89 86 87
Example 78 70 88 87 84 86 Example 79 80 85 84 82 84 Example 80 90
83 81 80 80 Example 81 100 81 79 76 77
[0160] As shown in Table 15 above, even if the extraction
temperature was changed from 25.degree. C. to 100.degree. C., the
extraction rate of the aromatic compounds in naphtha was almost 80%
or more, which confirmed that extraction efficiency was
excellent.
Examples 82 to 88
[0161] The aromatic compounds in naphtha were removed in the same
conditions and method as in Example 52, except that
[2-(1-butylimidazolium-3-yl-ethoxy)-ethyl]-1-butylimidazolium
bis(trifluoromethane sulfonyl)imide was used as the extraction
solvent. After the separation with a liquid-liquid extraction
method, the extraction solvent including the aromatic compounds was
discharged to a passage 5 of the lower end of the pulsed extraction
column and introduced into the evaporator 6 and deaerated in vacuum
under a specific condition.
[0162] At this time, the deaeration rate according to the
deaeration conditions such as the temperature, pressure, and time
was as shown in Table 16 below.
TABLE-US-00012 TABLE 16 Deaeration condition of hydrocarbons
Deaeration rate (%) Temperature Pressure Time Mixed thyl Class
(.degree. C.) (mmHg) (h) enzene Toluene Xylene benzene xample 82 20
70 2 90 94 96 95 Example 83 50 20 1 100 100 100 100 Example 84 70
70 2 100 100 100 100 Example 85 80 150 1 85 87 89 88 Example 86 100
50 1 100 100 100 100 Example 87 120 100 1 93 96 98 97 Example 88
150 30 0.5 100 100 100 100
[0163] As shown in Table 16 above, it could be confirmed that the
extraction solvent used in the removal process of aromatic
compounds was deaerated by diversifying the conditions such as
temperature (20 to 150.degree. C.), pressure (1 to 200 mmHg), and
time (10 min to 120 min), thus easily removing the aromatic
compounds.
Examples 89 to 92 and Comparative Example 3
[0164] The deaerated aromatic compounds were discharged to a
passage 7 of the upper end of the evaporator and introduced into a
condenser 8. The extraction solvent in which aromatic compounds
were removed was discharged to a passage 9 of the lower end of the
evaporator and again introduced into the extraction solvent inlet
passage 1 and reused.
[0165] At this time, the loss rate of the extraction solvent
according to the deaeration conditions was as shown in Table 17
below.
TABLE-US-00013 TABLE 17 Loss rate (%) of extraction solvent
according to a certain deaeration Class Extraction solvent
condition * Comparative Sulfolane 2~4 Example 3 Example 89
[2-(1-ethylimidazolium-3-yl- No loss
ethoxy)ethyl]-1-ethylimidazolium] bis(trifluoromethanesulfonyl)
imide Example 90 [4-(1-ethylpiperidinium-1-yl- No loss
butoxy)-butyl]-1-ethylpiperidinium bis(trifluoromethanesulfonyl)
imide Example 91 2-[2-(1-ethylpyridinium-1-yl- No loss
ethoxy)-ethoxy]-ethyl}- 1-ethylpyrrolidinium bis(tetrafluoroborate)
Example 92 (2-{2-[2-(4-ethylmorpholium-4- No loss
yl-ethoxy)-ethoxy]-ethoxy}- ethyl)-4-ethylmorpholium
bis(hexafluorophosphate) * Deaeration condition: 70 to 80.degree.
C., 50 to 70 torr, 120 min
[0166] As shown in Table 17 above, it could be confirmed that the
ether group-containing bis-imidazolium-based ionic liquid
extraction solvents and bis-biimidazolium-based ionic liquids could
be re-used in the extraction process without loss under certain
deaeration conditions.
Examples 101-105 and Comparative Example 11
[0167] In the separation of the aromatic compounds in naphtha
mixture using the pulsed extraction column, triethylene gylcol or
ionic liquids were introduced in the upper end of the pulsed
extraction column 3 via the extraction solvent inlet passage 1 at a
velocity of 5 mL/min under a room temperature condition, and at the
same time naphtha was introduced in the lower end of the pulsed
extraction column 3 via the naphtha inlet passage 2 at a velocity
of 1 mL/min. Thereby, the liquid-liquid extraction separation was
conducted at the pulsation velocity of 50 m/s for 3 h within the
pulsed extraction column.
[0168] After the liquid-liquid extraction separation, the raffinate
of upper-layer (naphtha mixture in which the aromatics had been
removed) was discharged to the passage 4 of the upper end of the
pulsed extraction column. The extraction rate of the aromatic
compounds was analyzed using gas chromatography (Young Lin
equipment, model #: YL6100), equipped with FID and FFAP
columns.
[0169] After the extraction, the extraction rate (extraction
removal rate) of the main aromatic compounds contained in each
extraction solvent was as shown in Table 21 below.
TABLE-US-00014 TABLE 21 Extration rate (%) Ben- Tolu- Mixed Ethyl
Class Extraction solvent zene ene xylene Benzene Comp. Sulfolane 28
14 12 15 Ex. 11 Ex. 101 Triethylene glycol 34 24 21 22 Ex. 102
1,1'-(1,2-ethanediyl) 97 94 92 93 bis(3-methyl-
imidazolium)bis(tri- fluoromethane sulfonyl)imide Ex. 103
1,1'-(1,4-butanediyl- 96 93 90 92 2-ol)bis(1-ethyl- pyrrolidinium)
bis(trifluoromethane sulfonyl)imide Ex. 104 1,1'-(2,3-butenediyl)
98 95 92 93 bis(1-ethyl- morpholinium)bis(tri- fluoromethane
sulfonyl)imide Ex. 105 1,1'-(1,4-butanediyl- 98 96 93 94
2,3-dione)bis(1-ethyl- piperidinium) bis(tri- fluoromethane
sulfonyl)imide
[0170] Referring to Table 21, it could be confirmed that, when
using the ionic liquids of Examples 102 to 105 having high
electronegativity as the extraction solvent, an interaction between
the ionic liquids and the aromatic compounds actively occurred,
thereby exhibiting excellent extraction effects as compared to
sulfolane of Comparative Example 11 and triethylene glycol of
Example 101, the extraction solvents having relatively low
electronegativity.
[0171] Further, it could be confirmed that when using the
triethylene glycol as the extraction solvent, it exhibited a higher
extraction effect than when using sulfolane as the extraction
solvent.
Example 106, 107 and Comparative Examples 12 to 16
[0172] The aromatic compounds were extracted from the naphtha
mixture by conducting a process in the same manner as in Example
101, except that
1,1'-(1,2-ethanediyl)bis(3-methylimidazolium)bis(trifluoromethanesulfonyl-
)imide was used as the extraction solvent and the used amount
(introduced amount) of the naphtha mixture was changed as shown in
Table 22 below.
[0173] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds was as shown in Table 22
below.
TABLE-US-00015 TABLE 22 Naphtha Extraction rate (%) mixture Ben-
Tolu- Mixed Ethyl Class (mL/min)* zene ene xylene benzene Example
106 0.25 100 100 100 100 Example 107 0.5 100 100 97 98 Example 102
1 97 94 92 93 Comparative 5 88 83 81 82 Example 12 Comparative 10
80 74 70 72 Example 13 Comparative 15 70 62 59 61 Example 14
Comparative 20 59 49 46 48 Example 15 Comparative 25 49 42 40 41
Example 16 *Amount of naphtha mixture applied based on 5 mL/min of
the extraction solvent includng the ionic liquids
[0174] Referring to Table 22 above, it could be confirmed that,
upon extraction of the aromatic compounds in naphtha, Examples 102,
106, and 107 in which the used amount (introduced amount) of
naphtha was 0.1 to 3% by volume with respect to 100% by volume of
the extraction solvent exhibited higher extraction efficiency than
Comparative Examples 12 to 16 at more than 90%.
Examples 108 to 110
[0175] The aromatic compounds in naphtha were extracted by a
process conducting in the same manner as in Example 101, except
that triethylene glycol was used as the extraction solvent and the
extraction was conducted by changing the number of times of
conducting the separation with the liquid-liquid extraction
method.
[0176] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds was as shown in Table 23
below.
TABLE-US-00016 TABLE 23 Number of times Extraction rate (%) of
conducting the Ben- Tolu- Mixed Ethyl Class separation step zene
ene xylene benzene Example 101 1 34 24 21 22 Example 108 2 55 48 44
45 Example 109 3 75 72 71 70 Example 110 4 94 92 90 92
[0177] Referring to Table 23 above, it could be confirmed that the
case of using triethylene glycol as the extraction solvent
exhibited excellent extraction efficiency of 90% or more as
compared to the case of conducting two to four multi-step
processes.
Examples 111 to 115
[0178] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 101, except
that
1,1'-(1,4-butanediyl-2-ol)bis(1-ethylpyrrolidinium)bis(trifluoromethanesu-
lfonyl)imide was used as the extraction solvent, and the velocity
of the pulsation generating motor in the pulsed extraction column
was changed as shown in Table 4.
[0179] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds was as shown in Table 24
below.
TABLE-US-00017 TABLE 24 Extraction rate (%) Velocity Ben- Tolu-
Mixed Ethyl Class (m/s) zene ene xylene benzene Example 111 10 87
86 85 86 Example 112 20 89 88 86 87 Example 113 30 91 90 88 89
Example 114 40 93 92 90 91 Example 103 50 96 93 90 92 Example 115
60 98 95 92 93
[0180] Referring to Table 24 above, when using the ionic liquids as
the extraction solvent, even if the pulsation injection velocity
within the pulsed extraction column was changed from 10 m/s to 60
m/s, the extraction rate of the aromatic compounds in naphtha was
85% or more, which confirmed that the extraction efficiency was
excellent.
Examples 116 to 123
[0181] The aromatic compounds in naphtha were extracted by
conducting a process in the same manner as in Example 101, except
that
1,1'-(2,3-butanediyl)bis(1-ethylmorpholium)bis(trifluoromethanesulfonyl)i-
mide was used as the extraction solvent and the extraction
temperature was changed as shown in Table 25 below.
[0182] After the extraction, the extraction rate (extraction
removal rate) of the aromatic compounds was as shown in Table 25
below.
TABLE-US-00018 TABLE 25 Extraction Extraction rate (%) temperature
Ben- Tolu- Mixed Ethyl Class (.degree. C.) zene ene xylene benzene
Example 14 25 98 95 92 93 Example 116 30 96 93 89 91 Example 117 40
94 91 86 88 Example 118 50 91 88 83 86 Example 119 60 88 86 81 84
Example 120 70 86 84 79 81 Example 121 80 83 82 77 79 Example 122
90 81 80 74 76 Example 123 100 78 77 70 72
[0183] Referring to Table 25 above, even if the extraction
temperature was changed from 25.degree. C. to 100.degree. C., the
extraction rate of the aromatic compounds in naphtha was 80% or
more, which confirmed that the extraction efficiency was
excellent.
Examples 124 to 130
[0184] The aromatic compounds in naphtha were removed in the same
conditions and method as in Example 101, except that
1,1'-(1,4-butanediyl-2,3-dione)bis(1-ethylpiperidinium)bis(trifluorometha-
nesulfonyl)imide was used as the extraction solvent. After the
separation with a liquid-liquid extraction method, the extraction
solvent including the aromatic compounds was discharged to the
passage 5 of the lower end of the pulsed extraction column,
introduced in the evaporator 6 and deaerated in a vaccum under
certain conditions.
[0185] At this time, the deaeration rate according to the
deaeration conditions such as the temperature, pressure, and time
were as shown in Table 26 below.
TABLE-US-00019 TABLE 26 Deaeration condition of hydrocarbons
Deaeration rate (%) Temperature Pressure Time Mixed Ethyl Class
(.degree. C.) (mmHg) (h) enzene Toluene xylene benzene Example 124
20 70 2 89 93 95 94 Example 125 50 20 1 100 100 100 100 Example 126
70 70 2 100 100 100 100 Example 127 80 150 1 84 86 89 88 Example
128 100 50 1 100 100 100 100 Example 129 120 100 1 92 95 98 97
Example 130 150 30 0.5 100 100 100 100
[0186] Referring to Table 26 above, it could be confirmed that the
extraction solvent used in the removal process of aromatic
compounds could be deaerated by diversifying the conditions such as
temperature (20 to 150.degree. C.), pressure (1 to 200 mmHg), and
time (10 min to 120 min), thus easily removing the aromatic
compounds.
Examples 131 to 135, and Comparative Example 17
[0187] The deaerated aromatic compounds were discharged to the
passage 7 of the upper end of the evaporator and introduced into
the condenser 8. The extraction solvent in which aromatic compounds
had been removed was discharged to the passage 9 of the lower end
of the evaporator, and again introduced into the extraction solvent
inlet passage 1 and reused.
[0188] At this time, the loss rate of the extraction solvent
according to the deaeration conditions of Table 27 below was as
shown in Table 27 below.
TABLE-US-00020 TABLE 27 Loss rate of extraction solvent according
to a certain deaeration Class Extraction solvent condition (%)
Comparative Sulfolane 2~4 Example 17 Example 131 Triethylene glycol
No loss Example 132 1,1'-(1,2-ethanediyl)bis(3- No loss
methylimidazolium) bis(trifluoro methanesulfonyl)imide Example 133
1,1'-(1,4-butanediyl-2-ol) bis(1- No loss ethylpyrrolidinium)
bis(trifluoro methanesulfonyl)imide Example 134
1,1'-(2,3-butenediyl)bis(1- No loss ethylmorpholinylinium)
bis(trifiuoromethane sulfonyl)imide Example 135
1,1'-(1,4-butanediyl-2,3- No loss dione)bis(1-ethyl-
piperidinium)bis(trifluoromethane sulfonyl)imide * Deaeration
condition: 70 to 80.degree. C., 50 to 70 torr, 120 min
[0189] Referring to Table 27 above, it could be confirmed that the
triethylene glcycol extraction solvent, the bis-imidazolium-based
ionic liquid extraction solvent, and the bis-biimidazolium-based
ionic liquid extraction solvent which were used in the present
process could be reused in the extraction process without loss
under certain deaeration conditions.
DESCRIPTION OF REFERENCE NUMERALS
[0190] 1: Extraction solvent inlet passage
[0191] 2: Naphtha mixture inlet passage
[0192] 3: Pulsed extraction column
[0193] 4: Passage of the upper end of the pulsed extraction
column
[0194] 5: Passage of the lower end of the pulsed extraction
column
[0195] 6: Evaporator
[0196] 7: Passage of the upper end of the evaporator
[0197] 8. Condenser
[0198] 9: Passage of the lower end of the evaporator
* * * * *