The authors acknowledge funding from Fonds de Recherche du Qu&#233;bec - Nature et Technologies, from Conseil Recherches en Sciences Naturelles et G&#233;nie (program INNOV) and PrimaQu&#233;bec.

1. Preparation of Poly(5-norbornene-2-carboxylic acid), PNBE(CO2H)
<ol>
	<li>Preparation of the monomer NBE(CO2H)
	<ol>
		<li>Weigh out acrylic acid (AA) (327 g, 4.5 mol, 2 eq.) and hydroquinone (4.9 g, 4.5 x 10-2 mol, 0.02 eq.) and add them to a 2 L round-bottom flask equipped with a condenser and a magnetic stir bar. Heat the flask at 150 &#176;C using a silicone oil bath.</li>
		<li>Once reflux is settled, add DCPD (300 g, 2.3 mol, 1 eq.) in a single portion, and then increase the temperature to 170 &#176;C.</li>
		<li>Leave the reaction at this temperature for 16 h. Observe the color change from clear to yellow-brown.</li>
		<li>Take a sample by extraction with a Pasteur pipet, and analyze it by 1H NMR (using CDCl3 as the solvent)15. Observe the apparition of NBE (double bond signals between 6.0 and 6.5 ppm, Figure 2 top).16</li>
	</ol>
	</li>
	<li>Purification of NBE(CO2H)
	<ol>
		<li>Replace the condenser with a simple distillation setup (one plateau) connected to a condenser in which cold water is circulated.</li>
		<li>Put the reaction setup under a vacuum set to approx. 1 mmHg. Heat the mixture at 100 &#176;C, and collect a clear liquid (ca. 40 mL) that can be discarded.</li>
		<li>Replace the collection flask with a 500 mL round bottom flask. Heat the oil bath to 155 &#176;C, and observe the dropwise distillation of NBE(CO2H) (317 g, 2.3 mol. Yield = 98%). The distillation takes over 7 h.</li>
		<li>Analyze the colorless liquid by 1H NMR to assess purity as well as endo:exo proportions (Figure 2, bottom).15 The endo:exo ratio changes with the time used for distillation as well as with the heating time used for the preparation of the crude NBE(CO2H). Typically, endo:exo ratios between 50:50 and 80:20 are obtained (60:40 in this case).</li>
	</ol>
	</li>
	<li>Polymerization of NBE(CO2H)
	<ol>
		<li>Place 300 g (2.3 mol, 5,000 eq.) of NBE(CO2H) in a 500 mL round bottom flask equipped with a magnetic stir bar. Degas the liquid by bubbling nitrogen for 30 min.</li>
		<li>Weigh allylpalladium(II) chloride dimer, [PdCl(C3H5)]2 (76 mg, 4.2 x 10-1 mmol, 1 eq. of Pd) and add it to the solution. Add silver antimonate AgSbF6 (180 mg, 5.2 x 10-1 mmol, 1.2 eq.).</li>
		<li>Under stirring, dissolve the Pd salt by heating at 70 &#176;C, and maintain the temperature at 70 &#176;C under a slight nitrogen flux. After 7 to 8 h, the stirring stops due to a viscosity increase.</li>
		<li>Stop the reaction after 36 h.</li>
		<li>Cool the round bottom flask with liquid nitrogen. With a spatula, break the polymer into small pieces.</li>
		<li>In a 2 L beaker equipped with a magnetic stir bar, add 750 mL of ethyl acetate. Add the polymer chunks to the ethyl acetate under vigorous stirring. Continue stirring for 2 h.</li>
		<li>Filter the solution over a 15 cm diameter Buchner funnel equipped with a paper filter (grade 413, 15 cm diameter).</li>
		<li>Wash the polymer with ethyl acetate three times (500 mL each washing). Dry the polymer (123 g, 9.4 x 10-1 mol, yield = 41%) in a vacuum oven set at 50 &#176;C for 12 h.</li>
	</ol>
	</li>
</ol>
2. Preparation of PNBE(vinyl)
<ol>
	<li>Polymerization of NBE(vinyl)
	<ol>
		<li>Degas toluene (ca. 200 mL) and NBE(vinyl) (ca. 200 mL) by bubbling with N2 for 30 min and place them in a glove box.</li>
		<li>Within the glove box, load toluene (100 g) in a 250 mL round bottom flask.</li>
		<li>Add Pd2(dba)3 (76 mg, 1.6 x 10-1 mmol, 1 eq. of Pd), AgSbF6 (68 mg, 2.0 x 10-1 mmol, 1.2 eq.) and triphenylphosphine, PPh3 (43 mg, 1.6 x 10-1 mmol, 1 eq.) successively to the toluene solution.</li>
		<li>Heat the mixture to 70 &#176;C until complete dissolution occurs. It occurs within 10 min.</li>
		<li>Add 100 g (8.0 x 10-1 mol, 5,000 eq.) of NBE(vinyl) to this purple solution.</li>
		<li>Stir at 70 &#176;C for 72 h.</li>
		<li>Remove the solution from the glovebox, and transfer the viscous black solution to a 1 L glass bottle containing a magnetic stir bar.</li>
		<li>Add toluene (200 mL) and stir.</li>
		<li>Add silica powder (silica gel 40-63 &#181;m, 10 g). Stir at room temperature for 16 h.</li>
		<li>Stop stirring and let the powder settle for at least 2 h in order for the silica particles to sedimentate.</li>
		<li>Filter the solution over a 15 cm diameter Buchner funnel equipped with a paper filter (grade 413, 15 cm diameter). Avoid pouring sedimented silica particles in the Buchner funnel.</li>
		<li>Rinse the silica particles with toluene (50 mL) and filter it through the Buchner funnel.</li>
		<li>Add methanol (1.2 L) to a 4 L beaker equipped with a magnetic stir bar.</li>
		<li>Add all of the toluene solution containing the polymer to the methanol gradually under vigorous stirring, and continue stirring for 30 min.</li>
		<li>Filter the polymer over a 15 cm diameter Buchner funnel equipped with a paper filter (grade 413, 15 cm diameter). Wash the polymer with three aliquots of methanol (400 mL each). Change the filter paper between each washing.</li>
		<li>Assess the polymer purity by 1H NMR in CDCl3, in order to see if the residual monomer is present (double bond signals between 6.0 and 6.3 ppm).15,16 If this is the case, continue washing with methanol.</li>
		<li>Dry the polymer (75 g, 6.3 x 10-1 mol, yield = 78%) under vacuum at room temperature overnight.</li>
	</ol>
	</li>
</ol>
3. Preparation of PNBE(epoxy)
<ol>
	<li>Epoxidation of PNBE(vinyl)
	<ol>
		<li>Add 150 g of dichloromethane to a 500 mL round bottom flask equipped with a magnetic stirrer and a condenser.</li>
		<li>Add PNBE(vinyl) (15 g, 1.3 x 10-1 mol, 1 eq.) with stirring until complete dissolution.</li>
		<li>Place the flask in an ice-bath and let it cool for 15 min.</li>
		<li>In a separate container, mix together formic acid (30 g, 6.5 x 10-1 mol, 5 eq.) and acetic acid (5 g, 8.3 x 10-2 mol, 0.6 eq.). Add the combined acids to the polymer solution.</li>
		<li>Let it cool for 15 min.</li>
		<li>Add hydrogen peroxide aqueous solution (30%) (75 g, 6.5 x 10-1 mol, 5 eq.) to the polymer solution.</li>
		<li>Stir for 18 h. The ice bath does not need to be removed, as the temperature will gradually increase to ambient temperature.</li>
		<li>Take a small sample, precipitate the polymer with acetone, and analyze it by 1H NMR in CDCl3.15 If the signal for the double bond (&#948; = 4.5-6.0 ppm) is sufficiently decreased (Figure 3), pass to the next step. Typically, the ratio of the integral of the double bonds to the other protons is less than 1:20 (1:83 in Figure 3). Otherwise, continue the reaction.</li>
		<li>Add acetone (750 mL) to a 4 L beaker equipped with a magnetic stir bar.</li>
		<li>Add the polymer solution to the acetone gradually under vigorous stirring for 15 min.</li>
		<li>Filter the polymer over a 15 cm diameter Buchner funnel equipped with a paper filter (grade 413, 15 cm diameter).</li>
		<li>Wash the polymer four times with acetone (200 mL each time).</li>
		<li>Change the filter paper between each washing.</li>
		<li>Dry the polymer (7.5 g) under vacuum at room temperature overnight.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 2" src="/files/ftp_upload/54552/54552fig2.jpg" /> 
Figure 2: 1H NMR spectra of crude (top) and purified (bottom) NBE(CO2H). The purified product is obtained by simple distillation. Note the peaks which are used to assess the endo:exo ratio. <a href="https://cloudfront-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54552/54552fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" src="/files/ftp_upload/54552/54552fig3.jpg" /> 
Figure 3: 1H NMR spectra of PNBE(vinyl) (blue) and PNBE(epoxy) (red). Note the ratio 1:3 between the integrals of the vinyl group (&#948; = 4.5-6.0 ppm) and the other protons in the PNBE(vinyl) spectrum. After reaction with H2O2, the ratio decreases to 1:83, thus confirming that epoxidation of vinyl group has occurred. <a href="https://cloudfront-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54552/54552fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" src="/files/ftp_upload/54552/54552fig4.jpg" /> 
Figure 4: FTIR spectra of PNBE(vinyl) (black) and PNBE(epoxy) acquired in attenuated total reflectance mode. Insert shows a zoom of the characteristic bands of PNBE(vinyl) and PNBE(epoxy). The 902 cm-1 and 992 cm-1 bands correspond to the C=C-H out-of-plane bending, whereas the 875 cm-1 band corresponds to the epoxide ring deformation. <a href="https://cloudfront-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54552/54552fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<ol>
	<li>Gaylord, N. G., Mandal, B. M., Martan, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peroxide-induced+polymerization+of+norbornene.">Peroxide-induced polymerization of norbornene.</a> J. Polym. Science, Polym. Lett. Ed. 14 (9), 555-559 (1976).</li><li>Janiak, C., Lassahn, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+vinyl+homopolymerization+of+norbornene.">The vinyl homopolymerization of norbornene.</a> Macromol. Rapid Comm. 22 (7), 479-493 (2001).</li><li>Bielawski, C. W., Grubbs, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Living+ring-opening+metathesis+polymerization.">Living ring-opening metathesis polymerization.</a> Prog. Polym. Sci. 32 (1), 1-29 (2007).</li><li>Blank, F., Janiak, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+catalysts+for+the+vinyl/addition+polymerization+of+norbornene.">Metal catalysts for the vinyl/addition polymerization of norbornene.</a> Coord. Chem. Rev. 253 (7-8), 827-861 (2009).</li><li>Kaminsky, W., Boggioni, L., Tritto, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cycloolefin+polymerization.">Cycloolefin polymerization.</a> Polymer Science: A Comprehensive Reference, 10 Volume Set. 3, 843-873 (2012).</li><li>Boggioni, L., Tritto, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=State+of+the+art+of+cyclic+olefin+polymers.">State of the art of cyclic olefin polymers.</a> MRS Bull. 38 (3), 245-251 (2013).</li><li>Goodall, B., Rieger, B., Baugh, L., Kacker, S., Striegler, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cycloaliphatic+polymers+via+late+transition+metal+catalysis.">Cycloaliphatic polymers via late transition metal catalysis.</a> Late Transition Metal Polymerization Catalysis. , 101-154 (2003).</li><li>Zhou, W., He, X., Chen, Y., Chen, M., Shi, L., Wu, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vinyl-addition+copolymerization+of+norbornene+and+polar+norbornene+derivatives+using+novel+bis(&#946;-ketoamino)Ni(II)/B(C6F5)3/AlEt3+catalytic+systems.">Vinyl-addition copolymerization of norbornene and polar norbornene derivatives using novel bis(&#946;-ketoamino)Ni(II)/B(C6F5)3/AlEt3 catalytic systems.</a> J. Appl. Polym. Sci. 120 (4), 2008-2016 (2011).</li><li>M&#252;ller, K., Jung, Y., Yoon, D. Y., Agarwal, S., Greiner, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vinyl-type+polymerization+of+alkylester-substituted+norbornenes+without+endo/exo+separation.">Vinyl-type polymerization of alkylester-substituted norbornenes without endo/exo separation.</a> Macromol. Chem. Phys. 211 (14), 1595-1601 (2010).</li><li>Boffa, L. S., Novak, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Copolymerization+of+polar+monomers+with+olefins+using+transition-metal+complexes.">Copolymerization of polar monomers with olefins using transition-metal complexes.</a> Chem. Rev. 100 (4), 1479-1494 (2000).</li><li>Funk, J. K., Andes, C. E., Sen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Addition+Polymerization+of+Functionalized+Norbornenes:+The+Effect+of+Size+Stereochemistry,+and+Coordinating+Ability+of+the+Substituent.">Addition Polymerization of Functionalized Norbornenes: The Effect of Size Stereochemistry, and Coordinating Ability of the Substituent.</a> Organometallics. 23 (8), 1680-1683 (2004).</li><li>Hennis, A. D., Polley, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel,+efficient,+palladium-based+system+for+the+polymerization+of+norbornene+derivatives:+Scope+and+mechanism.">Novel, efficient, palladium-based system for the polymerization of norbornene derivatives: Scope and mechanism.</a> Organometallics. 20 (13), 2802-2812 (2001).</li><li>Commarieu, B., Claverie, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bypassing+the+lack+of+reactivity+of+endo-substituted+norbornenes+with+the+catalytic+rectification-insertion+mechanism.">Bypassing the lack of reactivity of endo-substituted norbornenes with the catalytic rectification-insertion mechanism.</a> Chem. Sci. 6 (4), 2172-2182 (2015).</li><li>Commarieu, B., Potier, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrahigh+Tg+epoxy+thermosets+based+on+insertion+polynorbornenes.">Ultrahigh Tg epoxy thermosets based on insertion polynorbornenes.</a> Macromoecules. 49 (3), 920-925 (2016).</li><li>Pirrung, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Synthetic Organic Chemist's Companion. , (2007).</li><li>Kanao, M., Otake, A., Tsuchiya, K., Ogino, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereo-selective+synthesis+of+5-norbornene-2-exo-carboxylic+acid-Rapid+isomerization+and+kinetically+selective+hydrolysis.">Stereo-selective synthesis of 5-norbornene-2-exo-carboxylic acid-Rapid isomerization and kinetically selective hydrolysis.</a> Int. J. Org. Chem. 2 (1), 26-30 (2012).</li><li>Huertas, D., Florscher, M., Dragojlovic, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solvent-free+Diels-Alder+reactions+of+in+situ+generated+cyclopentadiene.">Solvent-free Diels-Alder reactions of in situ generated cyclopentadiene.</a> Green Chem. 11 (1), 91-95 (2009).</li><li>Pierre, F., Commarieu, B., Tavares, A. C., Claverie, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+Tg+sulfonated+insertion+polynorbornene+ionomers+prepared+by+catalytic+insertion+polymerization.">High Tg sulfonated insertion polynorbornene ionomers prepared by catalytic insertion polymerization.</a> Polymer. 86, 91-97 (2016).</li><li>Woo, H. G., Li, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Advanced functional materials, Chapter 1.6.8,30. 1, (2011).</li><li>Kim, D. -. G., Bell, A., Register, R. a. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Living+vinyl+addition+polymerization+of+substituted+norbornenes+by+a+t-Bu3P-Ligated+Methylpalladium+Complex.">Living vinyl addition polymerization of substituted norbornenes by a t-Bu3P-Ligated Methylpalladium Complex.</a> ACS Macro Letters. 4 (3), 327-330 (2015).</li><li>Seung, H., S, A., Baek, K., Sang, S., Intech, S. i. l. a. g. u. i. ,. M. .. A. .. ,. e. d. .. ,. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low+Dielectric+Materials+for+Microelectronics.">Low Dielectric Materials for Microelectronics.</a> Dielectric Material. , 59-76 (2012).</li></ol>

The authors have nothing to disclose.

The method proposed here is simple, and readily amenable to scale-up. All chemicals could be used as received without any purification. Note that performing the reaction at a lower scale (e.g. scales &#8804;1 g) usually yields lower yields due to an unavoidable loss of material during the handling and the collection.
The catalysts are formed in situ upon the reaction of commercial Pd compounds with cationizing agents. In our hands, the yield of the reaction as well as the characteristics of the polymer (e.g. molecular weight distribution) are not changed whether one starts with a well-defined catalyst such as (&#627;3-allyl)PdS2+ SbF6- (S = nitromethane) or with the in situ catalytic system. For the polymerization of NBE(vinyl), only an in situ form of the catalyst is currently known. We did not observe any reactivity difference between Pd2(dba)3 and Pd(dba)2, but the use of the chloroform adduct, Pd2(dba)3. CHCl3 is not recommended (lower yields are obtained). The polymerization reaction is also slightly air sensitive. Compared to a reaction entirely performed in the glove-box (O2 &#60;5 ppm), we obtained similar results in terms of yield and molecular weights when the reaction is performed with roughly degassed reagents (degassed by bubbling with N2, the catalyst still being weighed in the glove-box). The monomers do not need to be dried before use, but the presence of intentionally added water is not recommended, as water coordinates the catalyst and poisons the reaction. In fact, the catalyst (&#627;3-allyl)Pd(OH2)2+ SbF6- was found to be inactive.
The polymerization of NBE(CO2H) stops at 45% yield due to the formation of a solid (vitrification). The residual monomer is extracted with ethyl acetate. Ethyl acetate can be separated from monomer by rotary evaporation and the collected monomer can be engaged in a subsequent polymerization. The endo:exo ratio in the collected monomer is slightly different from the endo:exo ratio of the initial monomer. As we demonstrated in a previous work,13 the catalyst isomerizes the endo isomer to the exo isomer during polymerization but polymerization of the collected monomer proceeds in a similar fashion as the initial monomer.
With the exception of ethyl acetate, no other organic solvent is used for the preparation of PNBE(CO2H), starting from DCPD and acrylic acid. It is possible to replace the ethyl acetate extraction step by a Soxhlet extraction with water. This procedure also allows the separation of the unreacted monomer, leading to a reaction totally free of solvent, but it is tedious (the Soxhlet extraction lasted for two days in our hands).
The polymerization of NBE(vinyl) proceeds with 80% yield with a catalyst loading of 0.02 mol%. With a catalyst loading of 0.01 mol%, the yield decreases to 45%. The reaction stops due to the decomposition of the catalyst, and therefore, the yield is not improved by using longer reaction times. During the purification of the polymer, silica is added in order to remove residual metals. With this procedure, the polymer is virtually free of Ag, Sb and contains less than 15 ppm Pd, as measured by ICP.
The epoxidation of the polymer is performed by peracetic and performic acids formed in situ with H2O2 and the corresponding carboxylic acids. The filtration steps (3.1.11 and 3.1.12) should be performed without any interruption, and as rapidly as possible. Indeed, at this stage, the solid PNE(epoxy) is in contact with a large amount of acid and water, which leads to the ring opening of the epoxy functionality. To assess for the presence of ring-opened functionalities in the polymer, one can simply assess the solubility of the polymer in dimethylformamide (DMF). The ring-opened polymer is not soluble in DMF whereas PNBE(epoxy) is soluble in DMF.
We believe this method is significant because of the important role played by functional PNBEs in the fabrication of photoresists which are, for example, suitable for use in 157 nm photolithography.19 Functional PNBEs can also be employed for the construction of diblock copolymers.20 Due to their saturated hydrocarbon backbone, such polymers are interesting as low dielectric materials for microelectronics.21Recently, we also demonstrated that these materials lead to very high Tg thermosets14 as well as ionomers with possible applications for fuel-cell membranes.18 In view of the wealth of possible applications, the method presented here is of interest for a broad community.

Norbornene, NBE, the Diels-Alder adduct of ethylene and cyclopentadiene (obtained by &#34;cracking&#34; of dicyclopentadiene (DCPD)), is readily polymerized using either free-radical polymerization,1 cationic polymerization,2 ring-opening metathesis polymerization3 and catalytic insertion polymerization.4,5,6,7 Unlike the other mechanisms, the catalytic insertion polymerization leads to the formation of a very high glass-transition temperature (Tg) polymer whereby the bicyclic backbone of NBE is conserved. A variety of catalysts such as metallocene catalysts and late transition metal catalysts can be used to promote the polymerization of NBE.4,5,6,7 However, due to its low solubility and due to difficulties associated with the processing of a very high Tg polymer, the PNBE homopolymer has, to our knowledge, never found any use.
Functional polynorbornenes (PNBEs) have been the object of considerable scrutiny for the last 20 years, because they combine the high Tg imparted by the bicyclic rigid repeat unit as well as desirable properties endowed by their functionalities.8,9,10 NBE monomers are obtained from rather simple and inexpensive feedstocks, using a one-step Diels-Alder reaction between cyclopentadiene and a functionalized dienophile. However, the Diels-Alder reaction leads to two stereoisomers, endo and exo, which have very different reactivities.11,12 In fact, the endo stereoisomer is less reactive than exo form and deactivates the catalyst.11,12 Thus, in the past, the preparation of functional polynorbornenes usually required the separation of the endo and exo stereoisomers, and only the exo stereoisomer was used. Such a separation procedure was time-consuming, and led to the accumulation of unreacted endo stereoisomers as undesirable waste.
Recently we have shown that the polymerization of functionalized NBEs containing both stereoisomers is in fact feasible.13 We have thus been able to prepare a variety of substituted PNBEs, containing functional groups such as esters, anhydrides, aldehydes, imides, alcohols and double bonds. Due to their high Tg and functionality, these polymers show desirable properties. We describe here two methods to prepare functional polymers. The first one leads to the synthesis of the water soluble polymer poly(5-norbornene-2-carboxylic acid), PNBE(CO2H), using a cationic Pd catalyst (Figure 1).13,14 The same polymerization method can be used to prepare functional PNBEs with various pendant functionalities, such as esters, alcohols, imides, bromo-alkyls, aldehydes and anhydrides. In our hands, this cationic Pd catalyst cannot be used for NBEs containing pendant double bonds such as 5-vinyl-2-norbornene. In this case, a partial insertion of the pendant double bond during the polymerization leads to the formation of a cross-linked material. Therefore, we present here a second method dedicated to the formation of poly(5-vinyl-2-norbornene), PNBE(vinyl), using Pd2(dba)3:AgSbF6:PPh3 as an in situ catalyst.14 The pendant vinyl groups of the polymer are then further epoxidized, to lead to the formation of PNBE(epoxy) (Figure 1). Both PNBE(CO2H) and PNBE(epoxy) have been found to lead to the formation of thermoset resins with a Tg as high as 350 &#176;C.14 Thus, the simple method described here allows one to efficiently prepare polymers with a very high Tg and having a variety of functional groups, which can be used for numerous applications.
<img alt="Figure 1" src="/files/ftp_upload/54552/54552fig1.jpg" /> 
Figure 1: Functional PNBEs prepared by Pd catalyzed polymerization. (A) preparation of PNBE(CO2H), (B) preparation of PNBE(vinyl) and PNBE(epoxy). The dashed bond indicates a mixture of endo and exo isomers. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54552/54552fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="0" cellpadding="0" cellspacing="0" width="945">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">acrylic acid</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">147230</td>
			<td style="width:299px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">hydroquinone</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td>H9003</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">dicyclopendadiene</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td align="left">454338</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">palladium allyl dichloride dimer</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td>222380</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">silver hexfluoro antimonate</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">227730</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">liquid nitrogen</td>
			<td style="width:241px;">Local Facility</td>
			<td style="width:135px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">ethyl acetate</td>
			<td style="width:241px;">Fischer Scientific</td>
			<td>E14520</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">5-vinyl-2-norbornene</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">148679</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">toluene</td>
			<td style="width:241px;">Fischer Scientific</td>
			<td>T290-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">palladium dba</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">227994</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">triphenyl phosphine</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">93090</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">silica gel 40-63 microns</td>
			<td style="width:241px;">Silicycle</td>
			<td style="width:135px;">Siliaflash</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">methanol</td>
			<td style="width:241px;">Fischer Scientific</td>
			<td>BPA412-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">dichloromethane</td>
			<td style="width:241px;">EMD Millipore</td>
			<td>DX08311</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">formic acid</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">F0507</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">acetic acid</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td>320099</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:271px;">hydrogen peroxide solution</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">216763</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">acetone</td>
			<td style="width:241px;">Fischer Scientific</td>
			<td>A18-200</td>
			<td></td>
		</tr>
	</tbody>
</table>

a simple and efficient protocol for the catalytic insertion polymerization of functional norbornenes

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic nature of the monomer is conserved. The resulting polymer, polynorbornene, has a very high glass transition temperature, Tg, and interesting optical and electrical properties. However, the polymerization of functional norbornenes by this mechanism is complicated by the fact that the endo substituted norbornene monomer has, in general, a very low reactivity. Furthermore, the separation of the endo substituted monomer from the exo monomer is a tedious task. Here, we present a simple protocol for the polymerization of substituted norbornenes (endo:exo ca. 80:20) bearing either a carboxylic acid or a pendant double bond. The process does not require that both isomers be separated, and proceeds with low catalyst loadings (0.01 to 0.02 mol%). The polymer bearing pendant double bonds can be further transformed in high yield, to afford a polymer bearing pendant epoxy groups. These simple procedures can be applied to prepare polynorbornenes with a variety of functional groups, such as esters, alcohols, imides, double bonds, carboxylic acids, bromo-alkyls, aldehydes and anhydrides.

The NBE monomers are prepared by simple Diels-Alder reaction of DCPD and a suitable dienophile, for example acrylic acid (AA). Normally, DCPD is cracked to yield cyclopentadiene (CPD) before reaction.17 Freshly cracked CPD is then engaged in the Diels-Alder reaction. However, in this protocol, both cracking and Diels-Alder steps are performed concomitantly, in a one-pot reaction. Thus, as soon as CPD is formed, it reacts with AA to yield 5-norbornene-2-carboxylic acid, NBE(CO2H) (Figure 1A). After reaction, the crude NBE(CO2H) is purified by simple distillation (Figure 2). This procedure has been repeated with a variety of dienophiles (maleic anhydride13, allyl bromide18, allyl alcohol18, 1-octene18) in a consistent manner (high yields, purification by distillation (Figure 2). The reaction with butadiene as dienophile was not attempted, due to the inherent difficulties associated with the manipulation of butadiene. Interestingly, this reaction is solvent-less.
The polymers are obtained by catalyzed polymerization (Figure 1A and 1B) and collected under the form of dry powders. They are analyzed by 1H NMR, FTIR spectroscopy, and gel permeation chromatography (GPC). The 1H NMR analysis of the polymer (Figure 3) is used to diagnose the presence of leftover solvent and monomer (which appear as sharp peaks, in contrast to the broad resonance of the polymer). The 1H NMR analysis of PNBE(vinyl) (Figure 3 blue) and PNBE(epoxy) (Figure 3 red) permit the confirmation of the epoxidation of PNBE(vinyl). Indeed, the decreasing ratio between the integrals of the vinyl group and the other protons in the PNBE(epoxy) spectrum (1:3 to 1:83) proves the excellent conversion of the reaction (97% in this case). The FTIR spectroscopy can also be used to confirm the outcome of the epoxidation reaction, as shown by the apparition of a characteristic peak at 875 cm-1 (Figure 4) and the disappearance of the 904 and 992 cm-1 which are observed in the PNBE(vinyl) polymer. The GPC is used to confirm the molecular weight distribution of the polymers. Typical Mn for PNBE(CO2H) and PNBE(epoxy) are 100,000 g/mol and 20,000 g/mol, with a PDI comprised between 1.5 and 2.0.

Watch this Scientific Journal Video about A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes at JoVE.com

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes

We describe the catalytic insertion polymerization of 5-norbornene-2-carboxylic acid and 5-vinyl-2-norbornene to form functional polymers with a very high glass transition temperature.

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic ...

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10.3K Views.  Université de Sherbrooke. We describe the catalytic insertion polymerization of 5-norbornene-2-carboxylic acid and 5-vinyl-2-norbornene to form functional polymers with a very high glass transition temperature. 

Video: A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes

A Simple and Rapid Protocol for Measuring Neutral Lipids in Algal Cells Using Fluorescence

Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal fermentation processes and screening for new oil-rich strains requires a fast and reliable protocol for determination of intracellular lipid content. Current practices rely largely on gravimetric methods to determine oil content, techniques developed decades ago that are time consuming and require large sample volumes. In this paper, Nile Red, a fluorescent dye that has been used to identify the presence of lipid bodies in numerous types of organisms, is incorporated into a simple, fast, and reliable protocol for measuring the neutral lipid content of Auxenochlorella protothecoides, a green alga. The method uses ethanol, a relatively mild solvent, to permeabilize the cell membrane before staining and a 96 well micro-plate to increase sample capacity during fluorescence intensity measurements. It has been designed with the specific application of monitoring bioprocess performance. Previously dried samples or live samples from a growing culture can be used in the assay.

A simple protocol to determine the neutral lipid content of algal cells using a Nile Red staining procedure is described. This time-saving technique offers an alternative to traditional gravimetric-based lipid quantification protocols. It has been designed for the specific application of monitoring bioprocess performance.

Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal ...

Synthesis and Catalytic Performance of Gold Intercalated in the Walls of Mesoporous Silica

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties of the materials were investigated. We used a one pot sol-gel approach to intercalate gold nano particles in the walls of mesoporous silica. To start with the synthesis, P123 was used as template to form micelles. Then TESPTS was used as a surface modification agent to intercalate gold nano particles. Following this process, TEOS was added in as a silica source which underwent a polymerization process in acid environment. After hydrothermal processing and calcination, the final product was acquired. Several techniques were utilized to characterize the porosity, morphology and structure of the gold intercalated mesoporous silica. The results showed a stable structure of mesoporous silica after gold intercalation. Through the oxidation of benzyl alcohol as a benchmark reaction, the GMS materials showed high selectivity and recyclability.

Here, we present a protocol with a sol-gel process to synthesize gold intercalated in the walls of mesoporous materials (GMS), which is confirmed to possess a mesoporous matrix with gold intercalated in the walls imparting great stability and recyclability.

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties ...

Facile and Efficient Preparation of Tri-component Fluorescent Glycopolymers via RAFT-controlled Polymerization

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and efficient synthesis of well-controlled fluorescent statistical glycopolymers using reversible addition-fragmentation chain-transfer (RAFT)-based polymerization is demonstrated. The synthesis starts with the preparation of &#946;-galactose-containing glycomonomer 2-lactobionamidoethyl methacrylamide obtained by reaction of lactobionolactone and N-(2-aminoethyl) methacrylamide (AEMA). 2-Gluconamidoethyl methacrylamide (GAEMA) is used as a structural analog lacking a terminal &#946;-galactoside. The following RAFT-mediated copolymerization reaction involves three different monomers: N-(2-hydroxyethyl) acrylamide as spacer, AEMA as target for further fluorescence labeling, and the glycomonomers. Tolerant of aqueous systems, the RAFT agent used in the reaction is (4-cyanopentanoic acid)-4-dithiobenzoate. Low dispersities (&#8804;1.32), predictable copolymer compositions, and high reproducibility of the polymerizations were observed among the products. Fluorescent polymers are obtained by modifying the glycopolymers with carboxyfluorescein succinimidyl ester targeting the primary amine functional groups on AEMA. Lectin-binding specificities of the resulting glycopolymers are verified by testing with corresponding agarose beads coated with specific glycoepitope recognizing lectins. Because of the ease of the synthesis, the tight control of the product compositions and the good reproducibility of the reaction, this protocol can be translated towards preparation of other RAFT-based glycopolymers with specific structures and compositions, as desired.

An efficient, three-step synthesis of RAFT-based fluorescent glycopolymers, consisting of glycomonomer preparation, copolymerization, and post-modification, is demonstrated. This protocol can be used to prepare RAFT-based statistical glycopolymers with desired structures.

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and ...

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel &#945;-diimine ethylene polymerization catalyst. Initial polymerizations with the catalyst lead to optimized reaction conditions, including catalyst concentration, ethylene pressure and reaction time. Using gas-uptake data for these reactions, a procedure to calculate the initial rate of propagation (kp) is presented. Using the optimized conditions, the ability of the nickel &#945;-diimine polymerization catalyst to undergo chain transfer with diethylzinc (ZnEt2) during ethylene polymerization was investigated. A procedure to assess the ability of the catalyst to undergo chain transfer (from molecular weight and 13C NMR data), calculate the degree of chain transfer, and calculate chain transfer rates (ke) is presented.

A protocol for the high-throughput analysis of polymerization catalyst, chain transfer polymerizations, polyethylene characterization, and reaction kinetic analysis is presented.

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel ...

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 &#176;C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

An operationally simple procedure for the synthesis of ortho-trifluoromethoxylated aniline derivatives via a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxyacetamide followed by thermally induced intramolecular OCF3-migration is reported.

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

A Protocol for the Production of Gliadin-cyanoacrylate Nanoparticles for Hydrophilic Coating

This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic by a simple spray coating. These nanoparticles are produced by the polymerization reaction of alkyl cyanoacrylate on the surface of cereal protein (gliadin) molecules. Alkyl cyanoacrylate is a monomer that instantly polymerizes at RT when it is applied to the surface of materials. Its polymerization reaction is initiated by the trace amounts of weakly basic or nucleophilic species on the surface, including moisture. Once polymerized, the polymerized alkyl cyanoacrylates show a strong affinity with the object materials because nitrile groups are in the backbone of poly (alkyl cyanoacrylate). Proteins also work as initiator for this polymerization because they contain amine groups that can initiate the polymerization of cyanoacrylate. If aggregated protein is used as an initiator, protein aggregate is surrounded by the hydrophobic poly(alkyl cyanoacrylate) chains after the polymerization reaction of alkyl cyanoacrylate. By controlling the experimental condition, particles in the nanometer range are produced. The produced nanoparticles readily adsorb to the surface of most materials including glass, metals, plastics, wood, leather, and fabrics. When the surface of a material is sprayed with the produced nanoparticle suspension and rinsed with water, the micellar structure of nanoparticle changes its conformation, and the hydrophilic proteins are exposed to the air. As a result, the nanoparticle-coated surface changes to hydrophilic.

This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic. The produced nanoparticle is an assembly of gliadin-cyanoacrylate diblock copolymers. Spray coating with the produced nanoparticle changes the surface of target material to a hydrophilic surface.

This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic by a simple spray ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient radiolabeling of DBCO-group-functionalized gold nanoparticles using a copper-free click reaction. Radioiodination of the stannylated precursor (2) was carried out by using [125I]NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified 125I-labeled azide (1) was obtained with high radiochemical yield (75 &plusmn; 10%, n = 8) and excellent radiochemical purity (&gt;99%). For the synthesis of radiolabeled 13-nm-sized gold nanoparticles, the DBCO-functionalized gold nanoparticles (3) were prepared by using a thiolated polyethylene glycol polymer. A copper-free click reaction between 1 and 3 gave the 125I-labeled gold nanoparticles (4) with more than 95% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly indicate that the present radiolabeling method using a strain-promoted copper-free click reaction will be useful for the efficient and convenient radiolabeling of DBCO-group-containing nanomaterials.

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

A detailed procedure for the synthesis of a 125I-labeled azide and the radiolabeling of dibenzocyclooctyne (DBCO)-group-conjugated, 13-nm-sized gold nanoparticles using a copper-free click reaction is described.

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient ...

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of NixNb1-xO nanoparticles with different atomic compositions (x = 0.03, 0.08, 0.15, and 0.20) have been prepared by chemical precipitation. These NixNb1-xO catalysts are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The study revealed the sponge-like and fold-like appearance of Ni0.97Nb0.03O and Ni0.92Nb0.08O on the NiO surface, and the larger surface area of these NixNb1-xO catalysts, compared with the bulk NiO. Maximum surface area of 173 m2/g can be obtained for Ni0.92Nb0.08O catalysts. In addition, the catalytic hydroconversion of lignin-derived compounds using the synthesized Ni0.92Nb0.08O catalysts have been investigated.

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

A protocol for the synthesis of sponge-like and fold-like Ni1-xNbxO nanoparticles by chemical precipitation is presented.

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...