Formation of Styrene Carbonate from Styrene Oxide and CO2

Honors Organic Chemistry Lab Spring Semester 2017Dr. Deborah Lieberman & Dr. Allan Pinhas

Background to Honors Organic Lab Projects

● Synthesis of cyclic carbonates from epoxides and CO2 provides tremendous promise for converting this hazardous waste into industrially useful raw materials

○ Engineering plastics○ Cosmetics○ Polar solvents

● Honors Organic Lab investigates this synthesis of cyclic carbonates using variously substituted oxiranes and various catalysts

○ Significant findings■ Tetrabutylammonium iodide as simple salt catalyst provides the highest product yields■ High speed ball mill (HSBM) or “on the bench” reactions make fancy, expensive catalysts

unnecessary ■ H2O > THF > No solvent

Our Research Goal

● The goal of our research is to further determine optimal conditions and components to provide the highest yields of styrene carbonate using relatively inexpensive materials.

General Mechanism of Intended Reaction

Areas We Investigated

● Which iodide catalysts produce the highest yield of product● Which bromide catalysts produce the highest yield of product● How temperature is related to product formation● Which proportions of reactants produce the highest yields ● Which solvent between THF, H2O, and no solvent works the best● Which method of adding CO2 works the best

Methods: GCMS Sample Preparation

1.) Open steel vial noting if there is a hiss heard. 2.) Run IR 3.) Wash with diethyl ether until sample being retrieved is clear (about 3 pipets).4.) Remove bottom layer.

a.) If water, use pipetb.) If salt, gravity filter

5.) Place 3-5 drops of sample into GCMS vial.6.) Fill GCMS vial to top line with isopropyl alcohol. 7.) Label and place in GCMS.

Which Iodide catalysts will produce the highest yield of product with and without H2O as a solvent?

Erica Fastnacht and Sarah Han

Methods

Each reaction was run under controlled conditions. The components were added to a steel vial in the following order:

- Salt catalyst (0.15 mmol) - ammonium iodide (NH4), tetrabutylammonium iodide (TBAI), tetramethylammonium iodide (TMAI)

- Either 1.0 mL of solvent (water) or no solvent- Styrene oxide (1 mmol)- 0.1 g or 2.27 mmol of CO2 (dry ice)

Vials (w/ O-rings) were capped tightly and left at room temperature for one week, unless otherwise noted.

NH4I as the Catalyst

With H2O 12% 78% 4% 5%

No Solvent 79% 0% 9% 8%

91 g/mol(8 min)

107 g/mol(11 min)

121 g/mol(13 min)

164 g/mol(13.8 min)

TMAI as the Catalyst

With H2O 51% 8% 22% 16%

With H2O 10% 43% 18% 21%

No Solvent 60% 21% 0% 9%

91 g/mol(8 min)

107 g/mol(11 min)

121 g/mol(13 min)

164 g/mol(13.8 min)

TBAI as the Catalyst - Product Yields

*reaction time: 2 weeks instead of 1

Trial 1 Trial 2 Trial 3

With Water 73% 92%* 80%

Without Water 97%* 42% 91%

TBAI as the Catalyst

With H2O (1) 4% 11% 9% 73%

With H2O (2) 1% 4% 3% 92%

With H2O (3) 3% 3% 0% 80%

No Solvent (1) 1% 0% 0% 97%

No Solvent (2) 11% 37% 0% 42%

No Solvent (3) 7% 1% 0% 91%

91 g/mol(8 min)

107 g/mol(11 min)

121 g/mol(13 min)

164 g/mol(13.8 min)

Conclusion

● TBAI worked the best as a catalyst for the formation of styrene carbonate from styrene oxide and CO2 for the given reaction conditions, followed by TMAI and NH4I

● Results from the GCMS showed that the carbonate was the major product only when TBAI was used as the catalyst

● There is not enough data to conclude whether using water as a solvent has an effect on the yield of product

Possible Explanations - Solubility

● TBAI was visibly more soluble in styrene oxide than water

● NH4I was visibly more soluble in the water than the styrene oxide

Possible Explanation - Solubility

Possible Explanation - Solubility

● Since TBAI is the salt that is the most soluble in styrene oxide, it makes sense that it is the catalyst that produces the best yield, regardless of whether water is used

● NH4I and TMAI did not work as well because they are not as soluble in styrene oxide○ When run in water, the salts dissolve in the water and do not come in

contact with the styrene oxide, where the reaction is taking place○ When run with no solvent, the salts still do not incorporate into the

reaction because they do not become homogenous in the styrene oxide

Investigation of the Effects of Various Iodide Catalysts on Styrene Carbonate Formation in Tetrahydrofuran (THF) & Water (H2O)

Alaina Werling and Andrew (Scottie) Emmert

Experimental Approach

● Research Question: What combination of iodide salt catalyst and solvent leads to the optimal yield of styrene carbonate from styrene oxide & CO2?

● Experimental Timeline:

Week 1: NaI & THFWeek 2: NaI & H2O

Week 3: LiI & THFWeek 4: LiI & H2O

Week 5: NH4I & THFWeek 6: NH4I & H2O

Week 7: TBAI & THFWeek 8: TBAI & H2O

Methods

Reaction Preparation:● All reactions were performed under controlled conditions in a steel vial

containing the following reagents: ○ Iodide salt (in 1:1 molar equivalent with styrene oxide)

■ NaI, LiI, NH4I, C16H36NI (TBAI)○ Styrene Oxide (100 uL)○ Solvent (THF or H2O, 1000 uL)○ CO2 (extreme excess, “stuffed”)

● Insert O-ring into cap, tighten with vice grip, and allow to sit in bench for 1 week (168 hours*) until next lab period

○ *TBAI/THF sample in bench for 2 weeks (336 hours)

Conditions(8 minutes) (13.8 minutes) (11 minutes)

NaI/THF 21 63 0 0

NaI/H2O 27 16 16 38

LiI/THF 0 47 7 0

LiI/H2O 35 55 5 4

NH4I/THF 30 43 19 8

NH4I/H2O 6 21 32 0

TBAI/THF* 79 0 5 0

TBAI/H2O 7 5 5 83

(13 minutes)

120 g/mol 121 g/mol 164 g/mol 136 g/mol

NaI as Catalyst

● In THF - 0% product ● In H2O- 16% product

Conditions(8 minutes) (13 minutes) (13.8 minutes) (11 minutes)

NaI/THF 21 63 0 0

NaI/H2O 27 16 16 38

120 g/mol 121 g/mol 164 g/mol 136 g/mol

LiI as Catalyst

● In THF - 7% product ● In H2O- 5% product

Conditions (8 minutes) (13.8 minutes) (11 minutes)

LiI/THF 0 47 7 0

LiI/H2O 35 55 5 4

(13 minutes)

120 g/mol 121 g/mol 164 g/mol 136 g/mol

NH4I as Catalyst

● In THF - 19% product ● In H2O- 32% product

Conditions(8 minutes) (13 minutes) (13.8 minutes) (11 minutes)

NH4I/THF 30 43 19 8

NH4I/H2O 6 21 32 0

120 g/mol 121 g/mol 164 g/mol 136 g/mol

C16H36NI (TBAI) as Catalyst

● In THF - 5% product ● In H2O- 5% product

Conditions (8 minutes) (13.8 minutes) (11 minutes)

TBAI/THF 79 0 5 0

TBAI/H2O 7 5 5 83

(13 minutes)

120 g/mol 121 g/mol 164 g/mol 136 g/mol

Conclusions● Extreme excess of CO2 (i.e., packing vial with dry ice) possible culprit of low

styrene carbonate yields for time-tested salts○ TBAI/H2O reaction yields

■ Erica & Sarah: 80% yield■ Alberta & Divya: 71%■ Alaina & Scottie: 5%

● Iodide salts involving alkali and alkali earth cations (e.g., Na+ and Li2+) prevent ring closure due to strong, covalent character of oxygen-cation bond

○ Ring opens, but then sits there unable to react.

● Our results affirmed the idea that H2O is a better solvent than THF for this reaction.

● Some low yields could be due to CO2 gas escape. Some weeks we did not hear a hiss upon opening the steel vial (LiI/THF, LiI/H2O, TEAI/THF).

Covalent Character of Na+-O- & Li+-O- Bond Prevents Ring Closure in Formation of Styrene Carbonate

Does THF as a solvent improve product yield?

Alberta Negri and Divya Takkellapati

Methods

● Reaction Preparation:○ Wash and dry steel vial, making sure to replace o-ring for each trial○ Add reagents

■ 1 mmol of salt (TBAI or TEAI)■ 114 uL of styrene oxide■ Approximately .5 g of dry ice■ If applicable, 1 mL of solvent (H2O, THF, or dry THF)

○ Close vial immediately, using vice grip to ensure tightest seal

● Allow reaction to sit for 1 week at room temperature● Carry out product analysis (GCMS and IR readings)

ResultsSolvent Percentage of Product

None 2.84%

None 32.39%

Dry THF 15.45%

H2O 70.55%

Wet THF 77.28%

TBAI as Catalyst (1:1 molar ratio)

TEAI as Catalyst (1:1 molar ratio)

Solvent Percentage of Product

H2O 55.85%

Conclusions

● Initial results hinted THF might be an effective solvent (wet THF trial)

○ Further trials with dry THF and H2O support that THF alone does not noticeably increase

product yield

● Product yields were highest for reactions with H2O

as solvent

● TBAI is more effective salt than TEAI

○ Bulkiness of catalyst may play a role

● Important to replace O-rings after every trial

● Glass vials should not be stuffed with dry ice

Role of Carbon Dioxide’s Method of Addition in Styrene Carbonate Formation

Kyle Necamp and Nate Ranly

Baseline Experiments (dry ice directly added)

All of the experiments used: One mL of solvent, 114 microliters(0.996 mmol) of styrene oxide,

Tetrabutylammonium Iodide as the catalyst, and were run for one week.

Type of Vial Dry Ice (mmol)

Solvent Catalyst (mmol)

Percent of Product

Notable Peaks

Glass 65.89 water 0.2897 66.36 Styrene Oxide (15.04%)

Steel 22.72 water 0.277 84.21 Diol (7.76%)

Steel 0 water 0.145 0.36 Styrene Oxide (97.93%)

Steel 2.73 water 0.135 69.85 Diol (17.86%)

Steel 22.72 none 0.179 74.6 Styrene Oxide (23.41%)

Experimental Set Ups

Single 50 mL Erlenmeyer Flask System DataAll experiments run with tetrabutylammonium iodide, 114 microliters (0.996 mmol) of styrene oxide, and for one week in a single Erlenmeyer Flask system with the reaction vial separate from the dry ice.

Catalyst (mmol)

Solvent Volume (mL)

First CO2 Addition (mmol)

Second CO2 Addition (mmol)

Percentage of Product

Other Peaks

0.133 None None 67.7 97.7 3.7 Styrene Oxide (57%)Unknown* (28%)

0.137 THF 1.00 71.1 95.5 10.2 Sty. Ox. (72%)

0.135 Water 1.00 93.2 None 12.0 Sty. Ox. (80%)

0.14 Water 1.00 118 90.9 23.5 Sty. Ox. (67%)

0.14 Water 1.00 70.9 102 53.5 Unknown* (22%)

Parafilm Seal

Added

*Unknown present in Styrene Oxide Spectra

Two 50 mL Erlenmeyer Flask System DataAll experiments run with tetrabutylammonium iodide, 114 microliters (0.996 mmol) of styrene oxide, and for one week in a two Erlenmeyer Flask system with the reaction vial in a separate flask, connected by tubing from sidearm to sidearm, from the dry ice.

Catalyst (mmol)

Solvent Volume (mL)

First CO2 Addition (mmol)

Second CO2 Addition (mmol)

Percentage of Product

Other Peaks

0.148 Water 1.00 104 0 43.5 Styrene Oxide (46%)

0.120 Water 1.00 68.2 182 57.1 Sty. Ox. (20%)

0.14 Water 1.00 68.2 102 57.7 Unknown* (23%)CO2 bubbled into solution throughout reaction runtime

Two Round-Bottom Flask System DataAll experiments run with tetrabutylammonium iodide and 114 microliters (0.996 mmol) of styrene oxide in a two round-bottom flask system with the reaction vial in a separate flask, connected by tubing from spigot to spigot, from the dry ice.

Catalyst (mmol)

Solvent Volume (mL)

First CO2 Addition (mmol)

Second CO2 Addition (mmol)

Percentage of Product

Other Peaks

0.14 Water 1.00 114 125 10.7 Styrene Oxide (42%)Unknown* (35%)

0.14 Water 1.00 127 0 87.5 None of Significance

Reaction ran for two weeks instead of one

Conclusions

● Adding dry ice directly seems to be more effective.● The length of time the reaction is run should be investigated further.● The biggest problem was possible leaks in the set up.● Bubbling carbon dioxide directly into the reactants could be further

investigated.

Effects of Bromide Catalysts on Styrene Carbonate Formation

Sam Blizzard and Jumee Park

Setup

● Except where noted, all reactions:○ Used 13.75mmol (250microL) of water as solvent○ Used 1mmol (.44g) o f CO2○ Used 1mmol (114microL) of styrene oxide○ Conducted at room temperature (293K)○ Conducted in steel vial○ Conducted for one week○ Preparation for GCMS same as other groups and mentioned

previously

Non-TEAB catalysts

Catalyst Amount of Catalyst % of Product Notes

None 0 0

NaBr 1.75mmol (.18g) 15

CuBr2 .62mmol (.139g) 3

LiBr .4mmol (.036g) 20 Conducted over two weeks (Spring Break)

Tetrabutylammonium Bromide

.47mmol (.15g) 44

NH4Br 2mmol (.196g) 57 Conducted in glass vial

TEAB Catalysts

Conditions Amount of Catalyst Percent of Product Notes

Standard 3.3mmol (.7g) 82

Standard 3.3mmol (.7g) 29

Catalytic Amount of TEAB

.1mmol (.021g) 0 No hiss observed when opening vial

Temperature Increased to 333K

3.3mmol (.7g) 82 .09g lost after week- possible leak of CO2

THF used as solvent instead of H2O

3.3mmol (.7g) 26 .06g lost after week- possible leak of CO2

Conclusions● Amount of salt

○ Positive linear trend noticed, so standardize across experiments and use catalytic amounts for practical purposes

● Loss of CO2 noticed on some trials○ Look for avenues of experimentation that guarantee tighter seals

● TEAB generally stronger than other catalysts○ More experimentation with catalytic amounts○ Examine role of solubility of salts in water vs. styrene oxide

● Temperature could have effect○ More trials at more temperatures needed

● Test multiple identical trials at same time○ May need to test other catalysts again, as initial results determined whether to follow up with

further trials○ Addition of CO2 may add variability to process

Effects of Temperature on Styrene Carbonate Formation

Dean Hayes and Jordan Hill

Background

Question:

● Does temperature of the system significantly alter the amount of product obtained in a styrene oxide to styrene carbonate reaction?

Experimental set-up

● Salt: TBAI (0.27 mmol)● CO2: 1.2 grams (27mmol, excess)● Starting material: 100 uL (0.87mmol) ● Solvent: water (55mmol, 1mL)

Results

Results (Cont.)

10% of salt

Results (Cont.)

Less Salt

Conclusions

● Temperature has a significant effect on the amount of product obtained○ Increasing temperature increased desired product up to 333K○ At 333K and above, results were inconsistent and undesired products

increased in prevalence○ Parabolic pattern of product formation possible with temperature

change ● Decreasing the amount of salt appeared to inhibit product formation● In order to obtain more concrete conclusions, all the experiments should

be repeated several times

Overall Conclusions

● Concentration of CO2 used is not linearly correlated (the more you use does not mean the more yield you will get), but an optimal concentration does exist for this reaction.

● Water is a more effective solvent than THF○ Varying results for no solvent - could be due to different quantities of salt or CO2

● TBAI was frequently found to be the most effective catalyst● The procedure used led to inconsistent results in some cases

○ Same exact conditions led to different product yield

Future Directions

● Determine optimal amount of CO2 and catalyst to be used for maximum yields.● Further investigate relationship between solubility of catalyst in styrene

oxide/solvent and product yield● Standardize reaction preparation amounts for all materials amongst groups

participating in study.● Quantify product yields beyond GCMS percentages. ● Test how reaction runtime affects yield.● Modify experiment methods to increase the reproducibility of trials.● Measure the mass of the entire vial at the start and end of the reaction so the

amount of CO2 lost can be determined