Post on 28-Mar-2015
Organic Building Blocks Derived From Carbon Dioxide
Nickeisha StephensonStahl and Gellman groupsOctober 25th 2007
2
The Carbon Cycle
http://www.eo.ucar.edu/kids/green/images/carboncycle_sm.jpgLiu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
Since the pre industrial era CO2 levels have risen from 270 ppm-380 ppm
3
Where is our excess CO2 coming from
Transportation26%
Electrical Energy Production
36%
Industries24%
HeatingCivil Industrial
14%
Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
4
Industrial Sources of Carbon
Fossil raw materials
mineral oil, natural gas, coal
3
Basic products and intermediates
CO, methanol, arenes,ethylene oxide, etc.
300
End Products
plastics, fertilizers, plant protection agents,pharmaceuticals, etc.
30000
CO2
Organics
Chemical Products
Recycle
1013 tons of carbon finite resource
Atmosphere – 1014 tons carbon
Carbonates -1016 Tons carbon
5
Closing the Cycle
CO2 Capture
6
CO2 usage industrially
Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
7
Carbon Dioxide Produced Anually
26,100 Mt
CO2 ChemicallyTransformed Annually
120Mt
Large Available Carbon Feedstock
Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
8
Carbon Dioxide Thermodynamics
C (s) + H2 (g) CH4 (g)
C (s) + 2H2 (g) CH3OH (l)+ 1/2 O2 (g)
C (s) + 1/2 O2 (g) CO (g)
C (s) + O2 (g) CO2 (g)
Free Energy Of FormationCarbon Species
-50.75
-166.10
-137.15
-394.01
GfkJ mol-1
CO2 is carbon in its most oxidized form
Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
9
In Other Words
CO2
En
erg
y
Chemicalproducts
In order to make CO2 into a useful compound, energy needs to be supplied to reduce the oxidized species
Sources of Energy for CO2 Activation
1) Chemical
2) Photochemical
3) Electrochemical
4) Biological
Sakakura, T. Choi J-C., Yasuda, H.Chem. Rev. 2007, 107, 2365-2387
10
MO Diagram CO2
C OO+ --
[M] C
O
O
1. Salahub, D.R. and Russo, N., Metal Ligand Interactions: From atom Clusters, to surfaces, 1991; p 175-197
11
Some Not So Unfamiliar Reactions Of Carbon Dioxide
" Anhydrous Carbonic Acid"
MgBr+ CO2
OMgBr
O
NHR
R CO2 RN ONa
O
R
ONa
ONa
O
+
CO2+OHNaOH
Ether
Na metal
Liu, C-J., Mallison, R.G., Aresta, M., Utilization of Greenhouse gases, ACS Symposium Series, 2003
12
Basic CO2 Insertion Mechanism
CO2
Ln[M]
ECO
O
E
OLn[M]E
Ln[M]
E
O
C
O
OLnM
E = C, O, H,Elimination
Product
13
CO2
M-H
M-OM-C
C OH
OH OH
O H NMe2
OH O
OMe
O O
ORR
OO
R O
x
O O
O
R
14
Insertion into an M-C Bond
CO2
M-H
M-OM-C
C OH
OH OH
O H NMe2
OH O
OMe
O O
ORR
OO
R O
x
O O
O
R
15
Relative Rates of Insertion
RhPh3P
Ph3P PPh3 CO2 RhPh3P
Ph3P PPh3
OO
RhMe3P
Me3P PMe3CO2 Rh
Me3P
Me3P PMe3
OO
Vs.
PMe3 > PPh3
Increasing the basicity of the phosphine ligand, increases electron density on the metal, allowing for faster CO2 insertion
Kolomnikov, I.S., Gusev, A.O., Belopotapova, Grigoryan, M.Kh., Lysyak, T.V., Struchkov, Yu. T., Volpin, M.E J. Organometallic Chem., 1974, 69, C10-C12
16
RhMe3P
Me3P PMe3
CH3
CO2 RhMe3P
Me3P PMe3
OCH3
O
RhMe3P
Me3P PMe3CO2 Rh
Me3P
Me3P PMe3
OO
Vs.
Me > Ph
Decreasing electron withdrawing ability of R group, increases electron density at the metal center, thereby increasing CO2 insertion
Darensbourg, D., Grötsch, G., Wiegreff, P., Rheingold, A, Inorg. Chem., 1987, 26, 3827-3830
17
Benzoic Acid and Methyl Benzoate Formation
RhPh3P
Ph3P PPh3
OO
mineral acid OH
O
RhPh3P
Ph3P PPh3
OO BF3-MeOH, O
OMe
Reaction not catalytic
Kolomnikov, I.S., Gusev, A.O., Belopotapova, Grigoryan, M.Kh., Lysyak, T.V., Struchkov, Yu. T., Volpin, M.E J. Organometallic Chem., 1974, 69, C10-C12
18
Catalytic Formation of Benzoic Acids
Ar BO
O
CO2 (1 atm)
3 mol% [Rh(OH)(cod)]27 mol% dppp,3 eq. CsF
dioxane, 60ºCAr O
O
BO
O
OH
O
90%
OH
O
MeO 95%
OH
O
F3C 76%
OH
O
NH
O
O
88%
S
OHO
64%OH
O
CN63%
P P
dppp
Ukai, K., Aoki, M., Takaya, J., Iwasawa, N., J. Am. Chem. Soc. 2006, 128, 8706-8707
19
LnRh Ar
LnRh(I)
ArB(OR)2
Transmetalation
CO2Insertion
LnRhO Ar
O
ArB(OR)2 Ar O
O
BO
OTransmetalation
Ukai, K., Aoki, M., Takaya, J., Iwasawa, N., J. Am. Chem. Soc. 2006, 128, 8706-8707
20
Insertion Into M-O bonds
CO2
M-H
M-OM-C
C OH
OH OH
O H NMe2
OH O
OMe
O O
ORR
OO
R O
x
O O
O
R
21
Organic CarbonatesLinear
O O
OMeMe
Polycarbonate Synthesis
Solvent
Fuel Additive
Carbonylating and Alkylating agent
Cyclic
O O
O
Me
High boiling solvents
Reactive intermediates
Cosmetics
Antifreeze
http://img.alibaba.com/photo/50047975/Dimethyl_Carbonate.jpg
Electronics
Optical media
Sheeting
Water Bottles
2.7 million tons produced annually
OCH3
CH3
O
O
n
Polymer
22
Organic Carbonate Production
OCH3H3CO
O
2MeOH + Cl Cl
O+ 2NaOH + NaCl H2O+
2MeOH + 1/2O2 + COOCH3H3CO
O+ H2O
CuCl
Dimethyl Carbonate
Cyclic Carbonates
O O
O
+ Cl Cl
O+ 2 HClHO OH
Polymeric Carbonates
Cl Cl
OCH3H3C
HO OH
+
NaOH
CatalystO
CH3
CH3
O
O
nLexan
Tundo, P., Selva, M. Acc. Chem. Res. 2002, 35, 706-716ukuoka, S., Kawamura, M., Komiya, K., Tojo M., Hachiya, H., Hasegawa, K., Aminaka, M., Hirosige O., Fukawa, Konno, S Green Chemistry, 2003, 5, 497-507
23
Phosgene
O2 + 2C 800ºC 2 CO
NaCl + H2Oelectricity
Cl2+
NaOH
Cl Cl
O
Property COCOCl2 CO2
MAK value 30 ppm0.1 ppm 5000 ppm
Toxicity concern
greater affiniyfor hemoglobinthan O2
producesHCl in lungs
asphyxiationconcerns
LC50 2444 ppm110 ppm 100,000 ppm
Storagegas bottles or tanks
kilogram quantities.to be avoided
gas bottles or tanks
MAK = maximum allowable concentration in the work place
LC50 = Concentration lethal to kill 50% of a population
Used as a chemicalweapon during WWI
Leitner, W. Angew. Chem. Int. Ed. Engl. 1995, 34, 2207-2221
24
Dimethyl Carbonate: Phosgene Substitute
O
OCH3
O
CH3
Nu- Nu
OCH3
O+ CH3O-
Carboxymethylation: T~ 90ºC
O
OCH3
O
CH3Nu-
NuCH3 + CH3OCOO-
Methylation: T>120ºC
2MeOH + CO2 OCH3H3CO
O
+ H2O
But…
2MeOH + CO2 OCH3H3CO
O
+ H2O
Tundo, P., Selva, M Acc. Chem. Res. 2002, 35, 706-716Choi, J-C., He, L-N., Yasuda, H., Sakaura, T, Green Chemistry, 2002, 4, 230-234
25
Overcoming Thermodynamics
Adding drying agents to remove water
- Na(SO4)4, MgSO4, dicyclohexylcarbodiimide, PPh3 and molecular sieves did not help reaction
Dehydrating methanol, to eliminate the production of water
MeOH + OCH3H3CO
O
CO2
cat. Bu2Sn(OMe)2
180ºC, 24 h,drying agent
+ H2O
88% yield
Me Me
OMeMeO+
OCH3H3CO
OCO2
cat. Bu2Sn(OMe)2
MeOH, 180ºC, 24 h+
Me Me
O
Choi, J-C., He, L-N., Yasuda, H., Sakaura, T, Green Chemistry, 2002, 4, 230-234
26
Redesigning the experimental set up
MeOH + OCH3H3CO
O
CO2
cat. Bu2Sn(OMe)2180ºC, 24 h, 3A MS
46% yield
Choi, J-C., He, L-N., Yasuda, H., Sakaura, T, Green Chemistry, 2002, 4, 230-234
27
Polycarbonates and Cyclic Carbonates From CO2 and Epoxides
O
R+ CO2
CatalystO
O
R O
n+
O O
O
R
28
Heterogeneous Systems
O
H3C+ CO2 O
O
CH3 O
x
Catalyst
Catalyst System p(CO2) [atm] T [ºC] Time [h]
ZnEt2 / H2O 20-50 80 48(Inoue, 1969)
% Carbonate linkage
88
TOF [h-1]
0.12
Zn(OH)2 /
HO
O
OH
O30 60 40
(Hattori, 1981)
881.1
ZnO /
HO
O
OH
O25 60 40 >99
(Ree, 1999)
3.4
Ree. M, Bae, J.Y., Jung, J.H., Shin, T.J J. Polym. Sci. Part A 1999, 37, 1863-1876
29
Zinc Glutarate Catalysis
Ree, J. Cat 2003, 218, 386
Darensburg, Chem Rev. 2007, 107, 2388
ZnRO
RO
OR
OP
O
H3C
ZnRO
RO
OR
O
O C
CH3
P
ZnRO
RO
OR
O
CH3
OP
CO2
ZnRO
RO
OR
O
CH3
OP
CO
O
ZnRO
RO
OR
O
O CO
CH3
OP
ZnRO
RO
OR
O O
O CH3O
P
30
Salen complexes for polymerization
tBu O
N N
tBu
O
tBu
tBuCrCl
Reaction shows a first order dependence on catalyst
O
+ .04% cat,80ºC, 24h
60 atm
O O
On
99% carbonate linkageCO2
TOF [h-1]
5 equiv N-MeIm
7 equiv N-MeIm
0 equiv N-MeIm 28.5
88.2
0
Reaction with
N N
N-MeIm
Darensbouorg, D.J., Yarbrough, J.C.J. Am. Chem. Soc. 2002, 124, 6335-6342
O
Cr
Cl
Cr
Cl
L
ClO CrCrCl L
O
O
Cr
Cl
Cl
OCr
L
CO2
L = epoxide or N-Methylimidazole
Cl
O
OO
Cr
L
PO
OO
Cr
N
N
O
PO
OO
Cr
N
N
OO
Cr
N
N
O OP
O
Initiation
Propagation
32
Cyclic Carbonate Formation
tBu O
N N
tBu
O
tBu
tBuCrCl
Cr(III) salen
O
Cr
O OP
O
O O
OO
Cr
P+
O
R
0.07 mol% Cr(III) Salen DMAP, CH2Cl2 O O
O
R3.4 atm
+ CO2
75 - 85ºC
O O
O
H3C
O O
O
O O
O
O O
O
Cl
100% 98% 94% 99%
O O
O
100%
Paddock R.L., Nguyen, S.T, J. Am. Chem. Soc. 2001, 123, 11498-11499
33
Polycarbonate Produced from CO2, Industrially
CO2
OO O
O
O OMe
OMe
CH3OH
OH
O OPh
O
Ph
CH3H3C
HO OH
OCH3
CH3
O
O
nOHHO
H
H H
H + 1/2 O2O
H
H H
H
+ 3 O2 + H2OCO2
34
Insertion into a M-H bond
CO2
M-H
M-OM-C
C OH
OH OH
O H NMe2
OH O
OMe
O O
ORR
OO
R O
x
O O
O
R
35
Formic Acid
http://en.wikipedia.org/wiki/Image:Concrete-stave-silo.jpg, http://www.italymag.co.uk/images/bags1.jpg, http://www.osha.gov/SLTC/etools/hospital/hazards/images/latex.jpg
NR
RH H H
OH OH
O
N CHR
R HH+
heat
300,000 tons of formic acid produced annually
- Silage for animal food
- Coagulant for latex rubber
- Food additive
- Tanning and dyeing
36
Formic Acid Production
CH3OH + CO
80ºC, 45 atm NaOMe (cat.)
H O
OCH3 H2O
-CH3OHH OH
O
Current Industrial Route
Alternate Route
CO2 (g) + H2 (g) H OH
O
(l)
Cat.
One Pot Synthesis of Derivatives
H OH
OHNR2
HOR
H NR2
O
H OR
OCO2 + H2
Leitner, W., Angew Chem. Int. Engl. 1995, 34, 2207-2221
37
Unfavorable Thermodynamics
CO2(g) + H2(g)H OH
O
Gº = 32.9 kJ/mol ; Hº = -31.2 kJ/mol; Sº = -215J/(mol K)
CO2(g) + H2(g)H O-NH4
+
O
Gº = -9.5 kJ/mol ; Hº = -84.3 kJ/mol; Sº = -250J/(mol K)
+ NH3(aq)(aq)
CO2(aq) + H2(aq)
Gº = -35.4 kJ/mol ; Hº = -59.8 kJ/mol; Sº = -81J/(mol K)
NH3(aq)+H O-NH4
+
O
(aq)
Jessop, P.G., Tako, I., Noyori, R., Chem. Rev. 1995, 95, 259-272
38
Initial Catalytic System
Ru(H3C)3P
(H3C)3P H
H
P(CH3)3
P(CH3)3
CO2 + H20.1 mol cat, NEt3,H2O, C6H5, 20h
H OH
O
25 atm 25 atm TOF = 4
TOF = turn over frequency= mol HCOOH/ mol catalyst h-1
HC
O2H
Yie
ld (
mo
l/ m
ol c
at.)
Water added (mmol)
Hydrolysis rate determining step
Inoue, Y., Izumida, H., Sasaki,Y., Hashimoto, H., Chem. Lett., 1976, 863-864
39
Proposed Mechanism
L4[Ru]H2CO2
L4[Ru]H
H
CO
O
L4H[Ru]
H
O
C
O
H2O
L4[Ru]-O H
O
H OH
O L4[Ru]H(OH)
+H2
-H2O
Rate determining step
CO2 + H20.1 mol cat, NEt3,H2O, C6H5, 20h
H OH
O
25 atm 25 atm TOF = 4
Inoue, Y., Izumida, H., Sasaki,Y., Hashimoto, H., Chem. Lett., 1976, 863-864
Ru(H3C)3P
(H3C)3P H
H
P(CH3)3
P(CH3)3
40
Effects Base on Hydrogenation Reaction
Ru(H3C)3P
(H3C)3P Cl
O2CMe
P(CH3)3
P(CH3)3
CO2 + H20.3 mol cat, 5mmol base0.1 mmol MeOH, 1hr,50°C
H OH
O
20 atm 20 atm pKa =3.77
Base pKa ammonium ( H2O) Yield( mole acid/ mole base)
N
NN
N
N
NN
N(CF2CF3)3
N(CH2CH3)3
~-15.7
5.2
8.6
10.2
12
12.3
0
0
0.10
0.09
0.92
0.02
Base must be capable ofdeprotonating and stabilizingformic acid
Munshi, P., Main, A.D., Linehan, J.C, Tai, C-C., and Jessop, P.G., J. Am. Chem. Soc.,2002, 124, 7963-7971
41
Effects of Protic Source
CO2 + H20.3 mol cat, 5mmol base0.1mmol additive, 1hr,50°C
H OH
O
20 atm 20 atm pKa =3.77
Amine AdditivepKa additiveaqueous scale
yield mole acid/ mole amine
N
N
N(CH2CH3)3
pKa =10.7
pKa = 12
H2O
MeOH
C6F5OH
HBF4
MeOH
C6F5OH
15.7
15.5
5.5
0.5
15.5
5.5
0.6
0.9
0.66
0.19
2,6-tBu2C6H3OH ~11.7 0.001
0.92
1.36
Munshi, P., Main, A.D., Linehan, J.C, Tai, C-C., and Jessop, P.G., J. Am. Chem. Soc.,2002, 124, 7963-7971
42
Putting the Pieces Together
pKa
HC
O2H
yie
ld
(mo
l p
er m
ol
NR
3)
• Effective alcohols have aqueous pKa’s below that of the protonated amine
• Alcohols may help to facilitate CO2 insertion
Munshi, P., Main, A.D., Linehan, J.C, Tai, C-C., and Jessop, P.G., J. Am. Chem. Soc.,2002, 124, 7963-7971
43
Hydrogenation of CO2
• Despite the unfavorable thermodynamics for the hydrogenation of CO2 addition of an appropriate base and alcohol helps to over come these barriers
• Another strategy in bringing about CO2 hydrogenation would be to carry out the reaction in supercritical CO2
44
Supercritical CO2
Critical point (C) CO2
Temperature = 31.0°C
Pressure = 73.75bar
http://www.chemguide.co.uk/physical/phaseeqia/pdco2.gif
45
Increased Rates Observed in ScCO2
TO
F (
h-1
)
0
96,000
480
1,400
95,000
Ru
H2((
PM
e 3) 4
)
TH
F, T
EA
, 20
5 at
m,
50oC
Ru
H2((
PM
e 3) 4
)
C6H
5, T
EA
, H2O
50
atm
, R
T
Ru
H2(
(PM
e 3) 4
)
ScC
O2, T
EA
, MeO
H, 2
05 a
tm,
50oC
Ru
Cl(
OA
c)(
(PM
e 3) 4
)
ScC
O2, T
EA
, 12
0 at
m C
O2,
C6F
5O
H, 5
0oC
CO2 (g) + H2 (g) H OH
O
(l)
Cat.
Jessop, P.G., Tako, I., Noyori, R. Nature, 1994, 368, 231-233Jessop, P.G., Hsiao, Y., Ikariya, T., Noyori, R., J. Am. Chem. Soc., 1996, 118, 344-355Munshi, P., Main, A.D., Linehan, J.C, Tai, C-C., and Jessop, P.G., J. Am. Chem. Soc., 124, 7963-7971
46
Methyl Formate
Ru(H3C)3P
(H3C)3P Cl
Cl
P(CH3)3
P(CH3)3
CO2 (g) + H2 (g)
Cat., NEt3 MeOH, 80°C
200 atm 80 atm H OMe
OTOF = 68 h-1
47
H OH
OHNR2
HOR
H NR2
O
H OR
OCO2 + H2
Formamides and Alkyl Formates
48
FormamidesAddition of amine to the formic acid reaction results in the formation of formamides
Ru(H3C)3P
(H3C)3P Cl
Cl
P(CH3)3
P(CH3)3
CO2 (g) + H2 (g)
H OH
O
(l)
Cat. NHR2, 100°C
130 atm 80 atm H NR2
O+
Aminemole of product/ mole of cat.
Acid Amide
0
820
1500
14
950
0
NH(C6H11)2
NH(C2H5)2
NH(CH3)2
Jessop, P.G., Hsiao, Y., Ikariya, T., Noyori, R., J. Am. Chem. Soc., 1996, 118, 344-355
49
Conclusions
• Carbon dioxide is kinetic and thermodynamically stable, however, it can be activated in the presence of strong nucleophiles and metal complexes with high electron density at the metal center
• Insertion into a metal- element bond (M-C, M-H and M-O) leads to the formation of new compounds that can react further to produce more interesting compounds
• The field of carbon dioxide utilization is still in its infancy, but it needs to grow up in order to alleviate our dependence on fossil fuels. This can only come with further research and more academic interests in this field.
50
Future directions
• Mechanistic studies to better understand the role of additives and the elimination of carboxylate and catalyst regeneration in order to build better catalysts
• It would be ideal to carry out these reactions efficiently under 1 atm of CO2
• Development of new reactions
• Coupling coordination chemistry with electrochemistry
51
Acknowledgements
Prof. Stahl and Prof Gellman
Stahl and Gellman Groups
Practice Talk Attendees
Brian Popp Avery WatkinsChris Scarborough Holly HaaseAmanda King Olivia JohnsonLauren Huffman Jessica Menke Richard McDonald Tulay AtesinNattawan DecharinXuan Ye
Special thanks to Lauren Huffman and Jason Leonard, for keeping me sane