supporting information: renewable isoprene by … supporting...page 1 / 49 abdelrahman, et al....

/ 49 Abdelrahman, et al.

Supporting Information:

Renewable Isoprene by Sequential Hydrogenation of Itaconic Acid and

Dehydra-Decyclization of 3-Methyl-Tetrahydrofuran 1,†

Omar A. Abdelrahman, 1,2, †

Dae Sung Park, 1Katherine P. Vinter,

1,2Charles S. Spanjers,

1Limin Ren,

3Hong Je Cho,

1,2Kechun Zhang,

3Wei Fan,

1Michael Tsapatsis,

1,2,*Paul J. Dauenhauer

1. University of Minnesota, Department of Chemical Engineering and Materials Science, 421 Washington Ave. SE, Minneapolis,

MN, 55455 U.S.A.

2. Center for Sustainable Polymers, a National Science Foundation Center for Chemical Innovation. 209 Smith Hall, 207 Pleasant

Street SE, Minneapolis, MN, 55455 U.S.A.

3. University of Massachusetts Amherst, Department of Chemical Engineering, 686 North Pleasant Street, Amherst, MA 01003

U.S.A.

*Corresponding Author: [email protected] †Authors Contributed Equally.

TABLE OF CONTENTS

1.0 Materials…………………………………………………………….............................. 2

2.0 Catalyst Synthesis……………………………………………………………………… 3

3.0 Catalyst Characterization…………………………………………................................ 6

4.0 Reaction Methods: Flow Reactor……………………………………………………... 7

5.0 Reaction Methods: Microcatalytic reactor…………………………………………… 10

6.0 Reaction Methods: Itaconic Acid Hydrogenation…………………………………….. 11

7.0 Reaction Methods: MBDO dehydration to 3-MTHF……………................................. 11

8.0 Thermodynamic Calculations………………………………......................................... 12

9.0 Catalytic Experimental Results: Itaconic Acid Hydrogenation….................................. 14

10.0 Catalytic Experimental Results: 3-MTHF dehydra-decyclization…………………… 21

11.0 Catalytic Experimental Results: Isopropanol dehydration…………………………… 36

12.0 Product Identification: Mass spectrum fragmentation patterns………......................... 37

13.0 Experimental three-dimensional selectivity map……………..………......................... 43

14.0 Time-on-stream study of P-SPP catalyst……………………………………………… 48


1.0 Materials

1.1 Reagents and standard chemicals:

Itaconic acid (>99 %) and 2-methyl-1,4-butanediol (MBDO, >97 %) used for reactants in

aqueous-phase reaction were obtained from Sigma-Aldrich. 3-methyltetrahydrofuran (3-

MTHF,>95 %, TCI America) was used in gas-phase dehydra-decylization (Microcatalytic and

flow reactor) to make isoprene. Standards including isoprene (>99 %), 2-methyltetrahydrofuran

(>99 %), 3-methyl-3-buten-1-ol (>97 %), 2-methyl-3-buten-1-ol (>98 %) and α-methyl-ɤ-

butyrolactone (>98 %) were purchased from Sigma-Aldrich.

1.2 Catalysts

A variety of commercial catalysts were utilized in the vapor phase conversion of 3-

MTHF including ZSM-5 zeolite (Zeolyst CBV28014, Si/Al ratio = 140), H-Y zeolite (Zeolyst

CBV760, Si/Al = 30), tricalcium phosphate (TCP, Sigma Aldrich), silica alumina (SiO2·Al2O3,

Sigma Aldrich), niobium oxide (Nb2O5, Sigma Aldrich). For the aqueous production of 3-MTHF

from IA, 10 wt% Pd/C (Sigma Aldrich), 5wt% Ru/C (Sigma Aldrich), 5 wt% Pd/SiO2 (Strem

Chemicals), 5 wt% Ru/Al2O3 (Sigma Aldrich) and Amberlyst-15 (Sigma Aldrich) were

employed. In addition to commercially available catalysts, Sn-BEA, Pd-Re/C and various

phosphorous containing zeolites were prepared in house. Details of the preparation methods are

provided in subsequent sections.


2.0 Catalyst Synthesis

2.1 Pd-Re/C

The carbon supported Pd-Re catalysts were prepared using incipient-wetness

impregnation, where an incipient volume of 2 ml/g of catalyst was employed. Briefly, an

aqueous solution of ammonium perrhenate (NH4ReO4, Sigma Aldrich) was used to impregnate a

commercial Pd/C catalyst. Once impregnated, the catalysts were dried at 100 °C for 12 hr and

reduced at 400 °C in 10 % H2/Ar for 3 hr.

2.2 P-BEA

P-BEA was synthesized according to the literature [31]. Commercial zeolite Al-BEA (Zeolyst

CP814E, Si/Al = 12.5) was dealuminated by treatment with 70 wt % nitric acid (HNO3, Fisher

Scientific). Typically, 0.5 g of the Al-BEA was mixed with 25 mL of 70 wt % HNO3 in a Teflon-

lined stainless steel autoclave. The autoclave was then put into an oven at 80 °C for 24 h under a

static condition. The dealuminated zeolite BEA (DeAl-BEA) was washed extensively with

deionized water and dried overnight at 100 °C. In order to prepare P-BEA with Si/P = 27

(confirmed by ICP analysis), wet impregnation was performed by stirring 0.4 g of DeAl-BEA

and 18.2 µL of 85 wt% phosphoric acid (H3PO4, Sigma-Aldrich) in 3.33 mL of deionized water.

The impregnated sample was dried at 90 °C overnight, followed by calcination in a tube furnace

with dry air at 600 °C for 25 min


2.3 P-Al-BEA

P-Al-BEA was prepared by impregnation of H3PO4 on zeolite Al-BEA (Zeolyst,

CP814E, Si/Al = 12.5), according to the same procedure described in the preparation of P-BEA,

without the dealumination step.

2.4 P-SPP

P-SPP with Si/P = 27 (confirmed by ICP analysis) was synthesized according to the

literature [31]. Typically, tetra(n-butyl) phosphonium hydroxide (TBPOH, 40 wt %, Sigma-

Aldrich) as a structure-directing agent (SDA) was added dropwise into tetraethylorthosilicate

(TEOS, 98%, Sigma-Aldrich) under stirring. Deionized water was then added to this mixture,

and stirred for 24 h. The mixture became a clear sol with a composition of 1 SiO2 : 0.3 TBPOH :

10 H2O : 4 EtOH. The sol was sealed in a Teflon lined stainless steel autoclave and heated for 3

days in an oven at 115 °C. After crystallization, the solid product was extensively washed with

deionized water by centrifugation and decanting of the supernatant. This process was repeated

until the pH of the final supernatant was lower than 9. Subsequently, the collected sample was

dried at 90 °C overnight and calcined in a tube furnace at 550 °C for 12 h under dry air.

2.5 P-MFI

First, pure silica zeolite Si-MFI with a composition of 1 SiO2 : 0.26 TPAOH : 15 H2O : 4

EtOH was synthesized by mixing structure directing agent tetrapropylammonium hydroxide

solution (TPAOH, 40 wt%, SACHEM), water and tetraethylorthosilicate (TEOS, 98%, Sigma-

Aldrich). The mixed gel was sealed in a Teflon lined stainless steel autoclave and heated for 3

days in an oven at 180 °C. The solid products were centrifuged, washed with distilled water


(until pH<8) and then dried at 70 °C overnight and calcined at 550 °C for 6 h in air under static

conditions. In order to prepare P-MFI with similar P content as P-BEA, the same wet

impregnation procedure was performed for P-MFI as in preparation of P-BEA. First, 0.4 g of Si-

MFI, 18.2 µL of 85wt % phosphoric acid (H3PO4, Sigma-Aldrich) and 3.33 mL of deionized

water were mixed. Then, the impregnated sample was dried at 90 °C overnight, followed by

calcination in a tube furnace with dry air at 600 °C for 25 min.

2.6 Si-SPP

Si-SPP without P was synthesized by modifying P-SPP synthesis method. First, P-SPP

was synthesized according to the above procedures. Then, the calcined P-SPP solid products

were dispersed in water in a centrifuge tube. After the centrifuge tube was heated in a 70 °C oven

for 1 h, the solid products were separated by centrifugation. The dispersion and centrifugation

procedures were repeated until the suspension pH is around 7. Then, the solid products were

dried at 70 °C oven overnight and calcined at 500 °C for 4 h in air under static conditions. For a

better removal of P, the calcined products were dispersed in water and washed by centrifugation

for another 3 times. The final Si-SPP solid products were dried at 70 °C oven overnight and

calcined at 500 °C for 4 h in air under static conditions.

2.7 Pelletization procedure

In order to maintain a relatively uniform particle distribution and avoid excessive

pressure drops, catalyst powders utilized in the microcatalytic and packed bed reactors were

pelletized to achieve a particle diameter of 500-1000 µm. Briefly, 100-200 mg of catalyst powder

were placed into a 13 mm pellet press (Pike technologies) and pressed to 2 tons of pressure,

holding for 10-15 mins. The catalyst pellet was then extracted and broken up into smaller


particles, which were then passed through a set of sieves from which the 500-1000 µm sieve cut

was collected and used for catalytic testing throughout the study.

3.0 Catalyst Characterization

Textural information of the various catalysts employed in this study was characterized

through Ar physisorption in an Autosorb iQ2 porosimetry instrument (Quantachrom). Prior to

analysis, catalysts were outgassed at 573 K for 6 hours and subsequently cooled down to room

temperature under vacuum. BET specific surface area measurements were used to represent the

total surface area of the catalyst materials; total pore volume was determined using a single point

measurement at P/P0 = 0.97. Brønsted acid site concentration (H+) was determined by

isopropylamine temperature programmed desorption (IPA-TPD). Catalyst samples were

dehydrated at 400 °C under a stream of He for one hour then allowed to cool down to 120 °C

where the catalyst was contacted with IPA for 15 minutes. The catalyst was then held under a

stream of He for one hour to remove any physisorbed IPA, after which the temperature was

ramped at a rate of 10°C/min to 700 °C. IPA-TPD was not conducted for the phosphorous

containing materials, since earlier studies with P-containing materials did not result in any

detectable acidity[30]

.

Table S1. Catalyst Characteristics.

Catalyst Surface Area (m2 g

-1) Pore Volume (cm

3 g

-1) Si:Al

a H

+ (µmol g

-1)

ZSM-5 400 0.19 140 90

H-Y 720 0.36 30 350

SiAl 276 0.68 13 377

Sn-BEA 637 0.33 - -b

Nb2O5 8 0.07 - 30

a- Provided by the manufacturer

b- Cannot be determined by existing methods


Table S2. Phosphorous-containing Catalyst Characteristics.

Catalyst Surface Area (m2 g

-1) Pore Volume (cm

3 g

-1) Si:P

a

P-SPP 598 1.11 27

P-BEA 499 0.80 27.1

P-MFI 602 0.99 27

P-Al-BEA 552 0.84 27

Si-SPP 612 0.89 -

a- Determined by ICP-MS

3.1 ICP-MS

Elemental analysis was performed on inductively coupled plasma optical emission

spectroscopy (ICP-OES, iCap 6500 Dual view, Thermo Scientific) in Analytical Geochemistry

Lab, Department of Earth Sciences in University of Minnesota.

4.0 Reaction Methods: Flow reactor

The steady state measurements of the dehydra-decyclization of 3-MTHF to isoprene over

supported acid catalysts was performed in a downflow packed bed reactor. Liquid 3-MTHF was

fed into a vaporization section through a 1/16” PEEK capillary line (0.01” ID), where a syringe

pump (KDS-100, KD Scientific) equipped with a gas tight syringe (Hamilton Company)

controlled the liquid flow rate (50 µl/hr). The vaporization section consisted of an insulated

aluminum tube wrapped with a heating tape, inside where the liquid feed was vaporized and

swept with a helium carrier gas regulated by a mass flow controller (Brooks, 5850S). Helium

flow rates were adjusted according to desired reaction conditions anywhere between 30-100

sccm. The vaporized stream of 3-MTHF in helium was then passed through a switching section,

consisting of a heated 6-port valve (Vici Valco, DL6UWE), from which the stream could be sent

either directly to the analysis section or through the reactor first. The carbon balance across the

packed catalyst bed was calculated as per Eq. (S1)


��%� = ��

��∗ 100 (S1)

Analysis of the vapor stream as it by-passed the reactor and sent directly to the analysis section,

allowed the verification of the molar flow rate carbon in to the reactor. A direct measure of the

molar flowrate of carbon was possible given the quantitative carbon detector employed in the

analysis.

Details of the possible flow patterns are illustrated in Figure S1. The reactor consisted of a ½”

316 SS tube packed with quartz chips and catalyst operated in a down flow mode at 1.1 bar,

where the mass of catalyst loaded varied between 50 – 150 mg. The pressure drop across the

catalyst bed was maintained below 5% of the total pressure, achieved by maintaining the catalyst

particle diameter between 500-1000 µm. The catalyst bed was placed between two plugs of inert

quartz wool, above which the void volume was reduced using inert quartz packing in the range

of 850-4750 µm (Sigma Aldrich). Temperature measurements were made using a 1/16” type-K

thermocouple (Omega) placed directly below the catalyst bed, while a second thermocouple was

placed in the furnace used to control the temperature using a PID temperature controller

(OMEGA,CN-7800). Prior to introducing any reactant, the catalyst bed was heated at 3 K min-1

to 673 K and held for 1 hour under a 50 sccm stream of air. The catalyst bed was then cooled

down to the desired reaction temperature and flushed with a stream of He prior to introducing the

vapor phase reactant stream. Analysis of the vapor phase products was performed using an

online gas sampling gas chromatograph (Agilent, 7890A) equipped with a quantitative carbon

detector (QCD, POLYARC) in conjunction with a flame ionization detector (FID). Separation of

the various products and reactant in the GC were performed using an HP-PLOT Q column

(Agilent, 19091P-QO4).


Figure S1. Schematic of the Packed Bed Catalyst Flow Reactor. (a) Reaction Configuration. (b)

Reactor bypass configuration.


5.0 Reaction Methods: Microcatalytic reactor

Reactions to screen for catalysts and operating conditions were performed in a

microcatalytic reactor. The reactor consists of a glass reactor (i.e., inlet liner) placed in the inlet

of a gas chromatograph (Aglient 7890A). The reactor was packed with quartz wool below (7.5

mg) and above (15 mg) the catalyst (~45 mg). A diagram of the reactor is shown in Figure S2

below:

Figure S2. Diagram of high throughput pulsed flow reactor (HTPFR) implementing the

‘microcatalytic’ method.

Experiments were performed at reaction temperatures of 200 to 400 °C. The space

velocity was controlled by adjusting the carrier gas (He, 99.999%) flow rate to the split vent.

Space velocities of 0.9 – 180 s-1

were tested with the reactor, where space velocity is defined as

follows:

! = "#��$��%&' =()*

+,-=./%�01 (S2)

where FHe is the flow rate of He through in sccm min-1

and VC is the volume of the catalyst bed.

Helium pressure was kept constant at 30 psi. Each experiment was performed by injecting 1 uL


of pure 3-MTHF into the reactor followed by immediate separation and quantification of the

products. Reaction products were separated using a chromatographic column (Agilent, HP-Plot

Q, 30 m, 0.32 mm ID, 20 µm film thickness; temperature program: 40 ºC for 2 min, 10 ºC/min to

270 ºC, hold 10 min) followed by quantification using a quantitative carbon detector

(Polyarc/FID).

6.0 Reaction Methods: Itaconic Acid hydrogenation

Sequential hydrogenation and dehydration of itaconic acid (IA) for the production of 3-

MTHF was performed in a 100 mL high pressure Parr Reactor (model 4598HPHT, Parr

Instrument Co.). Typically, 1.5 g (11.5 mL) of IA was added to 28.5 mL of water, and 0.05 – 0.3

g of catalyst was introduced to the mixture. The reactor was purged with N2 twice to remove any

residual air in the reactor. The reactor was then pressurized to 500 – 1500 psig with H2 (at room

temperature) and heated to reaction temperature (100 – 220 °C) under vigorous stirring (1,000

rpm). Products were identified via GC-MS (Agilent 7890A connected with Triple-Axis MS

detector, Agilent 5975C) and quantified using a liquid sampling GC (Agilent 7890A) equipped

with a HP-Plot Q column and a QCD/FID combination.

7.0 Reaction Methods: MBDO dehydration to 3-MTHF

Dehydration of MBDO to 3-MTHF was performed in a 100 mL high pressure Parr

reactor. 1 mL (28.6 mmol) of MBDO was added to 29 mL of water, and 0.2 g of catalyst was

added to the mixture. The reactor was purged with N2 twice and pressurized to 200 psi to keep

reactants in the condensed phase. Reactions were performed at temperatures ranging from 100-

200 oC at a stirring rate of 1000 rpm. Products were identified via GC-MS (Agilent 7890A

connected with a Triple-Axis MS detector, Agilent 5975C) and quantified using a liquid

sampling GC (Agilent 7890A) equipped with a HP-Plot Q column and a QCD/FID combination.


8.0 Thermodynamic Calculations

Aqueous phase thermodynamic calculations were performed with the Gaussian 09 (Rev

C.1) program [32] using the M062X/6-311++G(3df,3pd) level of theory and the SMD model

[33] with water as the solvent for liquid phase calculations and the CBS-QB3 Complete Basis

Set method for calculations in the vapor phase. Vibrational frequencies, rotational temperature,

electronic energy, among other values calculated by Gaussian for each molecule are used to

calculate first, partition functions and finally thermochemical data resulting in Gibbs Free

energies. Each calculation considered contributions from translational, rotational, electric, and

vibrational energies to determine the overall partition function. All molecules are assumed to be

non-interacting, ideal gases. Theory and guidelines of this process can be found in the cited

resource by Ochterski [34]. The CBS-QB3 method was chosen due to its agreement (+ 1

kcal/mole), in most cases, to reported experimental data from NIST. The exception was found

with the reactions forming formaldehyde and propene. In this case, data reported by NIST was

included instead.

The Gibbs free energies of reaction were calculated by the following equation:

∆3 =∑ 5�3�6��7��8 −∑ 5:3:��8 (S3)

in which Gi, Gj correspond to Gibbs free energies calculated using Gaussian data and νi, νj

represent stoichiometric values for the given compounds in the chemical reaction of interest.

Another ability inherent in these calculations was to be able to examine sensitivity of ∆G

to varying experimental temperatures and pressures. However, trends of ∆G with respect to


pressure have been largely omitted from this work. This has been justified due to the negligible

change in ∆G in the ranges of pressures feasible to the reaction. Instead, focus has been directed

at temperature dependence.

Table S3. Calculated Free Energies of the Hydrogenation Products of Itaconic Acid.

Temperature (K) MGBL

(Kcal mol-1

)

MBDO

(Kcal mol-1

)

3-MTHF

(Kcal mol-1

)

Isoprenea

(Kcal mol-1

)

298 -44.7 -44.7 -52.8 -52.0

473 -43.7 -35.1 -48.2 -54.5

673 -41.8 -27.6 -44.3 -55.7 a- Vapor phase free energy relative to that of 3-MTHF


9.0 Catalytic Experimental Results: Itaconic Acid Hydrogenation

Table S4. Summary of the sequential hydrogenation-dehydration of itaconic acid (IA) to 3-

methyltetrahydrofuran (3-MTHF) over Ru-based catalysts.

Catalyst Temperature

(°C)

PHydrogen

(psig)

Conversion (%) Selectivity (%) Carbon

Balance

(%) IA 3-MTHF MBDO MGBL Others1

Ru/C (0.3g) 100 1,500 100 0.5 64.7 28.9 5.9 83.8

Ru/C (0.3g) 120 1,500 100 4.8 24.3 48.1 22.8 92.7

Ru/C (0.1g) 150 500 100 0.1 73.4 13.9 12.6 92.0

Ru/Al2O3 (0.3g) 100 1,500 100 0.5 46.5 44.7 8.3 86.5

Ru/Al2O3 (0.1g) 150 500 100 0.9 29.7 50.9 18.5 77.9

Ru/Al2O3 (0.05g) 200 500 100 0.2 90.3 6.3 3.2 95.8

Ru/C (0.3g) +

SiO2-Al2O3 (0.2g) 100 1,500 100 0.4 65.0 28.8 5.8 79.4

Ru/C (0.3g) +

Amberlyst-15

(0.2g)

100 1,500 100 3.2 60.8 32.0 4.0 93.8

Ru/C (0.1g) +

SiO2-Al2O3 (0.2g) 150 500 100 1.7 47.6 33.2 17.5 81.6

Ru/Al2O3 (0.05g)

+ SiO2-Al2O3

(0.2g)

200 500 100 0.8 56.3 30.1 12.8 84.3

Reaction conditions: 1.5 g (11.5 mmol) of IA in D.I. water (28.5 mL), H2 pressurized at room temperature) 1Others: 2-methyltetrahydrofuran, 2(or 3)-methyl-3-buten-1-ol and some unknown products.


Table S5. Summary of the sequential hydrogenation-dehydration of itaconic acid (IA) to 3-

methyltetrahydrofuran (3-MTHF) over Pd-based catalysts.

Catalysts Temperature

(°C)

PHydrogen

(psig)

Conversion (%)

Selectivity (%) Carbon

Balance

(%)

IA 3-MTHF MBO MBDO MGBL Others1

Pd/C (0.3g) +

Ru/C (0.2g) 120 1,500 100 0.2 0 78.7 16.3 4.8 93.5

Pd/C (0.3g) +

SiO2-Al2O3

(0.2g)

140 1,500 100 1.9 0 0 94.9 3.2 100.3

Pd/C (0.3g) +

SiO2-Al2O3

(0.2g)

160 1,500 100 4.5 0 2.2 83.2 10.0 96.2

Pd/ SiO2 (0.3g)

+ SiO2-Al2O3

(0.2g)

160 1,500 100 1.8 0 2.7 93.4 2.1 103.9

10Pd-10Re/C

(0.2g) 200 1,000 100 79.0 17.3 0.1 0.3 3.3 89.6

10Pd-5Re/C

(0.2g) 200 1,000 100 76.6 20.5 0.2 0.3 2.4 92.9

10Pd-10Re/C

(0.2g) 200 500 100 8.0 0 5.1 83.3 3.6 81.5

10Pd-10Re/C

(0.1g) 180 1,000 100 43.7 4.7 28.9 20.9 1.8 87.8

10Pd-10Re/C

(0.2g) 180 1,000 100 78.5 14.9 2.9 1.5 2.2 93.2

Reaction conditions: 1.5 g (11.5 mmol) of IA in D.I. water (28.5 mL), H2 pressurized at room temperature) 1Others: 2-methyltetrahydrofuran, 2(or 3)-methyl-3-buten-1-ol and some unknown products.


Figure S3. Yield to 3-MTHF from MBDO over various solid acid catalysts in the aqueous phase

at 100-200 oC under 200 psig of N2 after 24 hrs.


Figure S4. Results for the Sn-BEA catalyzed dehydration of MBDO to 3-MTHF. A) yield to 3-

MTHF at 130-200 °C and B) Conversion of MBDO and selectivity to 3-MTHF at 200 °C.


Figure S5. Comparison of various Ru based strategies for the sequential hydrogenation and

dehydration of IA to 3-MTHF at 100 °C under 1000 psi of H2 (Others: 2-methyl-tetrahydrofuran,

2-methyl-3-buten-1-ol, 3-methyl-3-buten-1-ol and unknown products). Reaction conditions: 1.5

g (11.5 mmol) of IA in D.I. water (28.5 mL), Ru/C and Ru/Al2O3 0.3 g, SiO2-Al2O3 and

Amberlyst-15 0.2 g.


Figure S6. Comparison of various Ru based strategies for the sequential hydrogenation and

dehydration of IA to 3-MTHF at 150 and 200 oC under 500 psi of H2 (Others: 2-methyl-

tetrahydrofuran, 2-methyl-3-buten-1-ol, 3-methyl-3-buten-1-ol and unknown products). Reaction

conditions: 1.5 g (11.5 mmol) of IA in D.I. water (28.5 mL), Ru/C and Ru/Al2O3 0.05 g, SiO2-

Al2O3 0.15 g.


Figure S7. Comparison of various Pd based strategies for the sequential hydrogenation and

dehydration of IA to 3-MTHF at 160, 180 and 200 oC under 1000 psi of H2 (Others: 2-methyl-

tetrahydrofuran, 2-methyl-3-buten-1-ol, 3-methyl-3-buten-1-ol and unknown products). Reaction

conditions: 1.5 g (11.5 mmol) of IA in D.I. water (28.5 mL), Pd/C, Pd/SiO2, Pd-Re/C 0.2 g,

SiO2-Al2O3 0.2 g.


10.0 Catalytic Experimental Results: 3-MTHF dehydra-decylization

Table S6. Microcatalytic summary of 3-MTHF dehydra-decyclization to isoprene over P-SPP

presented in Figure 3.

T(oC) SV (s

-1) Conversion (%) Selectivity (%)

Isoprene C3 C4 1,4 pentadiene 1,3 pentadiene (E,Z)

300 9.67 0.59 55.30 1.50 19.16 4.02 15.50

300 176.72 0.26 24.29 3.87 50.23 2.58 6.64

300 0.88 12.95 67.68 0.66 10.35 1.99 16.52

300 44.84 1.10 39.36 2.78 34.55 4.69 11.74

300 132.76 0.37 31.64 2.62 43.85 3.05 8.91

300 22.86 1.51 48.47 1.63 26.82 3.73 13.47

300 5.28 3.54 57.87 1.22 16.77 3.72 16.37

300 2.64 5.79 60.22 1.00 14.84 3.03 17.39

300 110.78 0.43 31.59 2.60 44.91 3.26 8.54

250 88.80 0.27 24.95 3.39 52.24 2.42 6.29

250 9.67 0.81 45.69 1.83 28.82 3.16 11.28

250 110.78 0.23 21.76 3.08 55.66 2.62 4.81

250 44.84 0.40 30.85 2.70 49.13 2.53 7.04

250 2.64 1.18 51.26 1.79 24.66 3.00 12.45

250 132.76 0.20 19.28 5.44 56.52 2.03 4.92

250 5.28 1.16 51.66 0.91 23.60 2.73 13.51

250 176.72 0.13 18.24 2.91 51.70 3.38 4.55

250 0.88 2.81 64.88 1.12 13.91 1.78 13.04

250 22.86 0.55 32.02 3.73 43.36 3.44 7.23

250 132.76 0.19 19.66 3.43 57.99 2.80 4.86

325 88.80 0.74 42.19 2.98 33.84 3.52 12.01

325 9.67 3.48 56.77 1.87 17.72 3.57 16.80

325 66.82 0.91 44.67 3.27 30.76 3.91 12.63

325 5.28 4.83 60.63 1.12 14.53 3.31 17.99

325 110.78 0.47 38.62 3.73 36.48 3.67 11.62

325 2.64 9.03 63.72 0.77 12.15 2.70 18.45

325 132.76 0.37 36.52 4.05 39.18 3.59 10.27

325 0.88 16.55 69.08 0.75 9.65 1.18 17.21

325 44.84 1.23 44.97 2.83 29.75 4.60 13.57

325 176.72 0.24 33.44 3.26 41.66 3.05 9.45

325 22.86 1.80 53.23 1.86 21.82 3.84 15.53

275 88.80 0.32 30.83 2.64 47.05 2.71 8.86

275 9.67 1.15 52.66 1.35 23.56 3.22 13.97

275 2.64 2.46 60.21 0.86 15.37 2.74 17.25

275 132.76 0.21 24.94 2.70 52.44 3.61 7.52

275 0.88 4.64 66.57 0.57 11.49 2.12 15.82

275 110.78 0.27 26.80 2.98 49.43 3.73 8.38


T(oC) SV (s



275 5.28 1.51 53.65 1.21 22.11 3.15 14.62

275 66.82 0.41 31.60 2.69 46.14 3.13 9.48

275 22.86 0.69 42.71 2.34 33.94 3.06 11.80

275 44.84 0.51 36.18 2.60 40.97 3.14 10.69

312.5 88.80 0.50 39.51 2.34 37.08 3.32 11.73

312.5 5.28 3.04 59.03 1.04 15.49 3.18 18.23

312.5 44.84 0.87 44.44 2.56 31.51 3.24 13.08

312.5 0.88 10.35 68.70 0.61 8.83 2.02 17.54

312.5 132.76 0.29 35.07 2.76 41.52 3.12 9.57

312.5 2.64 4.75 63.55 0.67 12.18 2.90 18.62

312.5 9.67 1.97 55.20 1.40 18.63 3.96 17.23

287.5 88.80 0.33 31.93 3.52 45.27 3.11 9.04

287.5 9.67 1.19 52.74 1.45 23.36 3.19 14.40

287.5 132.76 0.20 27.01 2.58 49.07 2.84 8.08

287.5 0.88 5.29 67.92 0.95 10.52 2.36 15.27

287.5 5.28 1.72 53.71 1.90 21.37 3.56 15.25

287.5 66.82 0.45 32.31 5.18 42.96 3.41 9.62

287.5 2.64 2.68 59.70 1.26 15.98 2.89 17.07

287.5 1.76 3.55 59.52 1.32 15.49 3.45 17.24

262.5 88.80 0.25 25.21 3.98 50.12 3.33 8.86

262.5 1.76 2.06 59.55 1.19 15.88 2.72 16.49

262.5 9.67 0.72 39.24 3.13 33.77 3.87 13.54

262.5 44.84 0.39 28.30 5.01 46.92 3.48 9.40

262.5 0.88 2.58 61.84 1.50 14.57 2.72 15.25

262.5 2.64 1.47 51.47 2.05 21.00 3.45 16.03

350 88.80 1.22 42.44 7.09 29.51 3.86 14.66

350 9.67 3.75 54.57 3.71 16.83 3.91 19.66

350 0.88 20.66 62.59 2.23 9.71 4.28 20.66

350 132.76 0.41 39.07 8.14 33.32 3.56 12.77

350 5.28 3.54 58.06 2.65 12.79 4.11 21.25

350 44.84 1.29 45.84 5.91 25.03 4.49 16.96

350 2.64 7.83 60.17 2.37 11.26 3.20 22.04

350 22.86 2.04 49.71 5.16 20.29 4.98 18.37

350 110.78 0.48 40.25 8.04 31.40 3.73 13.79

350 88.80 0.60 36.55 1.02 31.91 2.99 8.12

337.5 88.80 0.51 38.89 6.98 34.62 3.73 12.98

337.5 9.67 3.84 54.59 3.32 17.28 4.30 19.16


T(oC) SV (s



337.5 132.76 0.32 34.99 7.84 39.04 3.63 11.01

337.5 2.64 5.94 60.46 1.81 11.98 3.32 21.41

337.5 66.82 0.70 40.92 6.27 32.98 3.85 13.53

337.5 1.76 7.94 61.88 1.77 11.12 2.87 21.43

337.5 44.84 0.97 43.55 6.55 29.24 3.96 14.59

337.5 0.88 13.44 66.94 1.55 8.31 2.09 20.04

337.5 176.72 0.23 32.71 7.43 42.12 3.31 10.09

337.5 7.47 5.74 60.59 1.99 12.27 3.32 20.77

275 88.80 0.50 23.58 7.41 54.27 2.86 7.24

275 1.76 2.24 58.99 2.07 15.99 2.85 18.20

275 9.67 0.79 41.66 5.28 34.38 3.42 11.71

275 7.47 0.91 42.33 5.32 32.71 3.42 12.90

275 0.88 2.89 61.17 3.33 16.30 2.60 14.22

225 88.80 0.27 12.84 7.12 67.48 2.56 2.36

225 9.67 0.29 26.97 5.81 51.14 2.55 6.29

225 132.76 0.10 11.50 8.32 64.07 2.42 2.16

225 0.88 0.68 48.41 4.03 31.35 2.37 9.26

225 176.72 0.07 11.63 6.08 63.17 3.02 1.62

225 1.76 0.79 41.61 4.22 38.78 1.93 9.08

225 22.86 0.23 16.22 9.35 61.03 2.21 3.89

225 2.64 0.49 38.46 6.12 43.56 2.12 3.75

375 88.80 0.88 40.86 7.86 34.03 3.42 10.94

375 9.67 4.44 53.49 4.56 20.69 4.15 15.41

375 132.76 0.50 38.11 9.32 35.75 3.35 9.92

375 0.88 26.61 62.97 2.69 13.10 3.27 17.42

375 44.84 1.51 44.62 6.04 30.52 3.81 12.65

375 5.28 5.75 57.90 3.11 16.66 3.88 16.98

375 176.72 0.36 34.18 12.44 38.10 2.83 8.36

375 2.64 9.07 61.16 2.27 14.15 3.14 18.08

375 66.82 0.92 41.36 8.67 32.38 3.36 11.60

375 1.76 12.28 62.69 2.20 12.78 2.80 18.46

400 88.80 0.95 45.39 6.34 29.52 3.77 12.66

400 9.67 3.64 56.30 2.78 17.96 4.38 17.28

400 132.76 0.64 43.57 7.42 31.34 3.57 11.35

400 0.88 37.80 62.42 2.06 12.36 2.56 19.59

400 176.72 0.57 41.38 7.66 33.94 3.35 10.43

400 5.28 7.50 59.28 2.03 15.05 4.06 18.40

400 22.86 2.93 51.51 4.13 22.29 4.60 15.94


Figure S8. Distribution of produce C5 dienes including isoprene (red, ●), 1,4 Pentadiene (blue,

♦) and 1,3 Pentadiene (Cis and Trans, green, ▲) at conditions presented in Tables S6A-S6C.


Table S7. Summary of the dehydra-decylization of 3-methyltetrahydrofuran (3-MTHF) to

isoprene over Nb2O5 using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4

2 Isoprene Pentadiene

3

200 89 1.4 0.3 9.5 10.0 3.8

200 10 1.2 0.7 15.2 13.1 5.4

200 1 0.4 1.2 24.3 23.5 8.2

250 89 4.0 0.2 19.9 27.6 12.7

250 10 4.3 0.3 21.9 33.7 17.9

250 1 2.1 0.8 27.1 35.9 18.3

300 89 7.3 0.4 19.0 29.1 13.5

300 10 6.2 1.0 27.3 34.7 20.3

300 1 8.8 0.9 30.5 34.9 20.7

350 89 11.3 0.5 10.6 11.1 6.1

350 10 6.3 1.2 29.1 33.7 20.2

350 1 26.3 1.4 35.5 29.5 17.2

400 89 41.1 0.1 2.6 3.2 1.4

400 10 11.3 1.1 21.2 30.8 14.8

400 1 73.9 2.5 40.7 21.6 11.2

1C3: Propenes

2C4: Butenes and Butadienes

3Pentadienes: 1,3-pentadiene and 1,4-pentadiene



isoprene over H-Y using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 29.3 0.8 21.5 6.8 42.5

200 10 95.1 0.8 18.0 25.8 15.5

200 1 96.6 1.1 22.3 51.4 0

250 89 47.9 1.8 28.1 4.9 26.9

250 10 96.1 2.8 28.8 25.0 9.2

250 1 96.6 3.0 32.7 32.0 0.7

300 89 46.0 2.4 27.0 5.1 22.1

300 10 99.2 3.7 30.3 21.7 6.1

300 1 97.4 3.4 32.0 26.4 1.2

350 89 55.6 2.1 19.5 3.5 14.4

350 10 99.7 4.2 27.6 21.9 0

350 1 97.6 4.7 31.8 26.6 0

400 89 69.8 2.3 18.1 2.9 10.7

400 10 99.8 4.4 22.9 13.3 2.6

400 1 98.3 5.9 31.0 21.9 1.7

1C3: Propenes





isoprene over ZSM-5 using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 5.2 1.1 17.1 26.6 3.6

200 10 7.9 1.6 14.9 24.9 0.3

200 1 10.8 2.8 12.8 24.4 0.3

250 89 35.4 17.6 17.6 15.1 2.1

250 10 45.9 5.2 19.0 9.3 0.5

250 1 84.7 5.3 19.8 10.9 0

300 89 62.3 3.7 9.3 5.4 1.4

300 10 80.9 11.0 18.2 1.8 6.3

300 1 99.9 16.5 16.5 3.5 5.8

350 89 99.5 3.0 6.5 0.5 2.7

350 10 96.9 10.8 15.9 1.3 5.4

350 1 98.6 12.3 20.5 11.3 11.3

400 89 99.7 3.6 6.5 0.5 2.0

400 10 98.9 11.8 15.3 1.5 5.2

400 1 99.1 10.5 15.0 3.3 3.6

1C3: Propenes





isoprene over Sn-BEA using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 1.4 0.4 5.4 3.3 12.0

200 10 0.7 1.5 14.1 15.4 2.7

200 1 1.2 2.1 24.5 21.4 3.2

250 89 2.2 0 6.4 2.7 0.3

250 10 1.2 1.4 23.7 18.3 8.5

250 1 2.1 2.4 20.2 35.0 13.3

300 89 2.9 0.3 9.1 2.2 2.0

300 10 2.0 1.5 26.8 24.2 14.5

300 1 4.9 1.4 21.1 34.3 18.5

350 89 2.7 0.5 10.7 4.0 2.5

350 10 3.5 1.3 24.0 20.8 14.8

350 1 8.8 1.5 26.2 29.2 18.4

400 89 3.1 0.4 8.1 3.0 2.2

400 10 4.2 1.3 27.0 19.5 16.6

400 1 12.8 1.4 33.2 25.2 17.9

1C3: Propenes





isoprene over SiO2-Al2O3 using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 2.3 0.8 18.3 21.5 13.1

200 10 25.2 0.9 38.6 27.1 24.5

200 1 97.0 0.1 53.6 18.2 13.3

250 10 26.9 0.5 30.6 33.7 23.0

250 1 33.1 0.9 36.6 34.0 20.5

300 89 49.3 0.2 31.3 27.7 18.5

300 10 65.3 1.2 42.7 29.5 20.7

300 1 96.2 1.8 49.9 19.4 13.9

350 89 35.2 1.3 38.7 24.0 17.1

350 10 77.2 2.0 48.4 23.6 16.4

350 1 100 5.0 49.7 11.4 6.3

400 89 87.2 0.1 3.7 1.9 1.7

400 10 83.3 2.5 47.3 16.9 13.5

400 1 100 7.0 46.5 5.4 9.0

1C3: Propenes





isoprene over P-SPP using the microcatalytic method.

Temperature

(°C)

Space velocity

(S-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 0.2 2.4 25.8 40.9 11.4

200 10 0.7 0.7 12.8 66.0 14.7

250 89 9.5 1.3 19.4 55.5 16.1

250 10 2.4 0.6 10.9 67.0 18.8

300 89 1.0 1.1 19.1 56.7 17.9

300 10 5.7 0.6 8.7 68.2 21.1

300 1 26.7 1.3 11.6 66.2 17.2

350 89 1.4 1.0 13.1 61.7 20.5

350 10 11.8 0.6 7.6 67.4 23.2

350 1 40.6 2.7 20.1 54.6 20.8

400 89 2.6 0.8 9.7 64.2 23.2

400 10 19.1 0.6 7.5 65.4 25.0

400 1 63.8 3.3 23.7 48.1 22.4

1C3: Propenes





isoprene over P-MFI using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 0.2 2.7 75.2 3.5 6.6

200 10 0.4 2.3 67.9 12.3 4.3

200 1 0.7 1.9 55.0 25.0 5.2

250 89 0.9 1.1 76.2 13.5 3.5

250 10 1.3 3.1 64.4 16.8 5.1

250 1 2.8 2.0 45.8 33.1 9.3

300 89 0.9 3.1 67.4 16.4 4.6

300 10 2.2 3.5 50.4 27.5 9.1

300 1 7.0 1.9 30.2 46.1 13.9

350 89 1.0 4.3 55.3 23.1 7.7

350 10 3.7 2.9 37.4 36.9 14.6

350 1 18.3 1.2 18.9 57.5 18.8

400 89 1.3 3.6 42.9 31.0 13.1

400 10 6.4 2.1 28.1 42.7 20.2

400 1 40.2 1.0 15.0 57.7 24.3

1C3: Propenes





isoprene over P-BEA using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 0.2 2.0 54.6 15.2 6.2

200 10 0.4 1.3 39.1 33.2 6.8

200 1 1.7 1.1 31.7 37.4 8.6

250 89 0.4 0 35.2 39.4 15.9

250 10 1.3 1.3 37.1 34.7 12.5

250 1 3.3 0.8 23.1 57.7 13.1

300 89 1.1 1.2 48.5 28.9 12.6

300 10 3.4 1.8 34.6 37.4 16.2

300 1 11.7 1.5 20.9 52.8 17.1

350 89 1.3 1.7 43.1 29.3 16.2

350 10 7.5 2.0 28.8 40.5 21.9

350 1 29.0 2.8 22.7 49.4 18.5

400 89 2.5 1.8 36.3 30.3 23.3

400 10 14.4 1.9 25.8 39.6 27.6

400 1 56.4 3.4 25.6 33.9 18.8

1C3: Propenes





isoprene over P-Al-BEA using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 18.1 3.5 38.2 26.4 7.5

200 10 100 1.9 28.8 18.6 8.8

200 1 100 0.7 36.2 30.7 8.7

250 89 47.3 1.9 33.8 11.7 4.1

250 10 100 2.9 30.5 17.9 3.6

250 1 100 1.1 39.7 22.9 2.5

300 89 56.7 3.8 32.3 7.5 3.1

300 10 100 6.0 34.8 15.6 1.6

300 1 100 2.4 44.9 18.9 1.4

350 89 55.9 8.4 42.7 9.7 4.7

350 10 100 8.5 35.4 12.9 1.8

350 1 100 5.6 49.6 16.5 1.5

400 89 75.7 9.8 38.4 7.8 4.6

400 10 100 11.1 36.6 10.9 2.1

400 1 100 10.7 48.5 11.3 2.3

1C3: Propenes





isoprene over tricalcium phosphate using the microcatalytic method.

Temperature

(°C)

Space velocity

(s-1

)

Conversion

(%)

Selectivity (%)

C31 C4


3

200 89 0.03 10.7 16.4 26.6 6.8

200 10 0.04 1.2 23.0 21.2 20.0

200 1 0.04 1.6 25.2 18.2 20.7

250 89 0.05 11.1 16.7 18.1 20.2

250 10 0.07 2.4 32.7 16.9 14.8

250 1 0.13 3.0 39.4 11.3 11.6

300 89 0.07 14.2 29.8 19.5 16.1

300 10 0.16 4.7 36.8 13.0 11.8

300 1 0.30 8.0 41.5 10.9 10.2

350 89 0.16 12.5 29.7 16.5 11.4

350 10 0.34 10.3 35.9 11.3 10.5

350 1 0.60 12.3 37.8 10.5 10.3

400 89 0.30 14.9 31.6 12.0 10.6

400 10 0.60 14.1 36.7 9.4 9.2

400 1 1.03 11.6 36.9 7.7 8.2

1C3: Propenes




Table S17. Packed bed reactor summary of 3-MTHF dehydra-decyclization to isoprene over

SiO2.Al2O3.

T (oC)

WHSV

(g 3-MTHF gcat-1

hr-1

)

P3-MTHF

(torr)

Selisoprene

(%)

Selpentadiene

(%)

Conversion

(%)

Carbon Balance

(%)

300 0.70 1.54 35.3 56.6 15.3 104.7

315 0.70 1.54 32.6 54.8 20.7 96.7

330 0.70 1.54 31.3 52.6 29.0 101.3

350 0.70 1.54 28.8 49.0 45.1 100.1

Table S18. Packed bed reactor summary of 3-MTHF dehydra-decyclization to isoprene over P-

SPP.

T (oC)

WHSV

(g 3-MTHF gcat-1

hr-1

)

P3-MTHF

(torr)

Selisoprene

(%)

Selpentadiene

(%)

Conversion

(%)

Carbon Balance

(%)

275 0.36 1.54 55.2 75.6 4.3 93.5

300 0.36 1.54 59.8 80.7 6.4 97.3

315 0.36 1.54 61.3 83.4 8.4 97.2

325 0.36 1.54 62.3 85.0 9.8 107.5


11.0 Catalytic Experimental Results: Isopropanol dehydration

To assess the performance of the packed bed reactor, the dehydration reaction of

isopropanol to propene was examined over the silica alumina catalyst. Typically, alcohol

dehydration reactions exhibit a near zero order dependence in alcohol partial pressure and an

apparent activation barrier of approximately 100 kj mol-1

under kinetic control [35,36]. At 398

K, the reaction order in isopropanol was measured to be 0.18 ± 0.03 with an apparent barrier of

92.3 ± 11.4 kJ mol-1

. Uncertainty in kinetic measurements are reported at a 95% confidence

level.


12.0 Product identification: Mass Spectrum Fragmentation Patterns

Verification of the identity of product chemical compounds was conducted through the

injection of standards and comparison with retention times by gas chromatography. In addition,

the microcatalytic method was coupled with a gas chromatography system with a mass

spectrometer detector. In a manner identical to which the microcatalytic method was

implemented (Section 5.0), a quartz tube packed with catalyst was placed in the liner of a GC

equipped a mass spectrometer detector. Shown in Figures S9-S13 are the mass spectrum

fragmentation patterns of the various products detected in the course of applying the

microcatalytic method to a P-SPP catalyst with 3-MTHF as the injected reactant.


Figure S9. Mass spectrum fragmentation pattern of isoprene A produced over P-SPP from 3-

MTHF using the microcatalytic method at 400 oC B NIST mass spectrum fragmentation pattern

library


Figure S10. Mass spectrum fragmentation pattern of 1,3 Pentadiene A produced over P-SPP

from 3-MTHF using the microcatalytic method at 400 oC B NIST mass spectrum fragmentation

pattern library


Figure S11. Mass spectrum fragmentation pattern of 1,4 Pentadiene A produced over P-SPP

from 3-MTHF using the microcatalytic method at 400 oC B NIST mass spectrum fragmentation

pattern library


Figure S12. Mass spectrum fragmentation pattern of butene A produced over P-SPP from 3-


library


Figure S13. Mass spectrum fragmentation pattern of propene A produced over P-SPP from 3-


library


13.0 Experimental three-dimensional selectivity map

An advantage of the microcatalytic method is the ability to rapidly screen multiple

reaction conditions. Given that injections of the reactant (3-MTHF) were performed using a GC

automated liquid sampler, a variety of reaction conditions could be sampled through an

automated process (GC software). Automated GC software permits the organization of inlet

condition sequences (i.e. long lists of temperature and flow conditions / space velocity).

Therefore, in an effort to identify the reaction conditions that optimize the production of the

desired product, isoprene, a grid of 112 reactions conditions was tested. The grid of points

spanned twelve different temperatures ranging from 225 to 400 oC, in addition to fourteen

different space velocities ranging from 0.9 to 180 s-1

.

To avoid systematic errors, the order of experimental trials with varying reaction

temperature and space velocity depicted in Figure 3 was randomized. Also, given the nature of

the reaction chemistry, oxygenated hydrocarbons reacting over solid acid catalysts, deactivation

through coke deposition was present. Not accounting for parasitic phenomena such as

deactivation can unfortunately lead to misleading representations of catalytic data. Therefore, to

avoid the manifestation of artifacts resulting from catalyst deactivation, reference conditions

were routinely utilized to ensure all catalytic data was compared equally. Once the catalyst was

first placed on stream, a reference condition was selected and tested multiple times in a row to

establish a catalytic baseline. Using this catalytic reference point, a bracketing technique was

employed to explore a new condition followed by a return to the reference point. Essentially,

every data point was “bracketed” on either end by the reference condition. This bracketing

technique was continuously applied throughout the process of constructing the reaction


conditions grid, allowing us to ensure that all catalytic data was compared relative to the same

reference point established with a pristine catalyst.

Once collected, the data at all conditions was arranged by temperature and space velocity

with their corresponding selectivity to each of the products. This grid of catalytic information

was then plotted in MATLAB, where a colored contour plot could be created using existing 3D-

plotting tools. Given the discrete nature of the data collected, data interpolation was required to

create a three-dimensional continuous contour plot. Presented in Figure 3 of the text is the

contour plot created through interpolation via polynomial smoothing of the overall data set. The

data was first empirically fit to a 5th

order polynomial in both temperature and space velocity

while minimizing the residual error. Illustrated in Figure S14 is the parity plot between the

polynomial fit (5th

order) and the experimental data for isoprene selectivity where reasonable

agreement is obtained. It is worth noting that no form of extrapolation was applied to the data

set.


Figure S14. Parity plot of the fifth order polynomial fit (Figure 3) of isoprene selectivity versus

experimental data.

Alternatively, a linear interpolation can be applied as shown in Figure S15, where the

data between two experimental points is calculated to be a linear average; linear interpolation by

this method is a MATLAB built-in function. The trends of selectivity to products appear to be

the same when comparing the resulting plot (Figure S14) to that in Figure 3 of the text; isoprene

formation is favored at low space velocities and an intermediate temperature of ~ 325 oC. The 3D

plot resulting from linear interpolation, however, is more textured, which is likely the result of

experimental variability. The linear interpolation, however, provides a tighter fit of the

experimental data, shown in the parity plot for isoprene selectivity in Figure S16.


Figure S15. Linear Interpolation Depiction of Figure 3. A three-dimensional plot of 112

experimental measurements of selectivity to isoprene (large panel), pentadienes (upper right),

and butane/propene (lower right). The color map is presented using a linear interpolation of the

experimental data.


Figure S16. Parity plot of the linear interpolation fit (Figure S15) of isoprene selectivity versus

experimental data.


14.0 Time-on-Stream (TOS) Study of P-SPP Catalyst.

To evaluate the long-term activity of P-SPP catalyst and selectivity to dienes, we have

also evaluated the stability of the P-SPP catalyst during the course of 3-MTHF dehydra-

decyclization at 325°C and a partial pressure of 5.5 torr. Shown in Figure S17 is the 3-MTHF

conversion profile with time on stream (TOS), where the conversion drops from 43% initially to

16% after approximately 18 hours on stream. Interestingly, the selectivity to dienes appears to

increase initially, where the selectivity to isoprene and dienes (isoprene plus 1,3 pentadiene)

stabilizes at approximately 66 and 86 %, respectively. Throughout the course of evaluating the

catalyst’s stability, the carbon balance was maintained at an average value of 98%.

Figure S17. Time-on-stream study of isoprene production. The vapor-phase conversion (blue, ●) of

3-methyl-tetrahydrofuran was selective to isoprene (orange, ●) and dienes (isoprene + 1,3-pentadiene,

grey, ●). The carbon balance (yellow, ●) of each experiment equals 100% within experimental error.

Catalyst: P-SPP, Temperature: 325 °C, Partial pressure: 5.5 torr.


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