Magnetic Fe@g-C3N4: A Photoactive Catalyst for the Hydrogenation

Subscriber access provided by DALHOUSIE UNIV

Article

Magnetic Fe@g-C3N4: A Photoactive Catalyst for the Hydrogenation of Alkenes and Alkynes Mallikarjuna N Nadagouda, R. B. Nasir Baig, Rajender S. Varma, and Sanny Verma ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.5b01610 • Publication Date (Web): 28 Jan 2016 Downloaded from http://pubs.acs.org on January 31, 2016

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

ACS Sustainable Chemistry & Engineering is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

Magnetic Fe@g-C3N4: A Photoactive Catalyst for the Hydrogenation of Alkenes and Alkynes R. B. Nasir Baig b†, S. Verma a†, Rajender S. Varma a and Mallikarjuna N. Nadagouda b* a

Sustainable Technology Division, National Risk Management Research Laboratory, U. S. Environmental Protection Agency, MS 443, Cincinnati, Ohio 45268, USA. b WQMB,WSWRD, National Risk Management Research Laboratory, U. S. Environmental Protection Agency, Cincinnati, Ohio 45268, USA E-mail: [email protected] † Equal contribution

Abstract A photoactive catalyst, Fe@g-C3N4, has been developed for the hydrogenation of alkenes and alkynes using hydrazine hydrate as a source of hydrogen. The magnetically separable Fe@g-C3N4 eliminates the use of high pressure hydrogenation and the reaction can be accomplished using visible light without the need for external sources of energy.

Key words Photo-catalysis, Hydrogenation; Nano-ferrite, Graphitic carbon nitride, Heterogeneous catalysis,

Introduction The hydrogenation of double and triple bonds using metals such as Pd, Rh, Pt, Ru and their complexes have been customarily used in pharmaceutical and petrochemical industries although they increase the cost of the production. These reactions often involve the use of highly flammable and explosive hydrogen gas under high pressure conditions.1-2 Consequently, cost effective and safer protocols are being explored for hydrogenation chemistry. Progress has been made using first row transition-metals for the catalytic hydrogenation of alkenes and alkynes. Recent discoveries involve the use of metals and metal oxide nanoparticles due to their homogenous equivalence in terms of surface area. Commonly, these nanoparticles have been

ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

immobilized over solid supports for increased activity and ease of recyclability. Iron nanoparticles have been immobilized over polystyrene and used for the hydrogenation of alkene but the reaction requires the use of hydrogen at high pressure.3 To circumvent this drawback of high-pressure hydrogenation, iron and cobalt complexes were specially designed. However, these catalysts are poisoned under the reaction conditions, resulting in the accumulation of metal waste.4-5 Although iron nanoparticles immobilized over graphene surfaces have been employed for the hydrogenation reaction with better activity as compared to earlier reports, they still require 20 bar pressure and extended reaction time to hydrogenate olefins.6 Replacing high pressure hydrogen with hydrazine could also performed this reaction at elevated temperature. However, the use of graphene as a support is highly non recommendable due to complexity in synthesis and risk of exposure to graphene dust.7 Thus, the discovery of a heterogeneous catalyst that could accomplish the aforementioned transformation at ambient conditions is desirable as it could eliminate the use of high pressure hydrogen.8, 9 In this continuation of our research on the

Scheme 1 Synthesis of Fe@g-C3N4 development of a sustainable protocol in organic synthesis

10-13

and magnetically separable

heterogeneous catalysts,14-17 herein, we report the first example that demonstrate the use of graphitic carbon nitride surface (g-C3N4) for the immobilization of iron ferrite (Scheme 1) and its application in photocatalytic hydrogenation using hydrazine at room temperature.


Page 2 of 14

Page 3 of 14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Results and discussion The first step was to design and develop magnetically active photo catalysts that could facilitate hydrogenation of double and triple bonds. The motive was to use the most sustainable energy source: visible light; the source would make the procedure environmentally efficient and adoptable for industries and academicians. Graphitic carbon nitride has been synthesized without the generation of any hazardous product in pure form which is not the case with some other carbon based support.18 Additionally, it has an affinity towards visible light

19, 20

which can

overcome the energy barrier leading to the formation of the desired products. Thus, we combined g-C3N4 with an iron oxide nanoparticle which in turn, provided a synergic jump for hydrogenation. Ferrous sulfate was immobilized over a graphitic carbon nitride surface, reduced, and caged into g-C3N4 cavities as iron oxide. The important aspect in using Fe@g-C3N4 as a photo catalyst for the hydrogenation was to find an effective stoichiometric ratio of iron oxide and g-C3N4 support.21 Accordingly, Fe@g-C3N4 was prepared with different weight percentage of iron and screened towards the photo-catalyzed hydrogenation of styrene using hydrazine as a source of hydrogen at room temperature (Table 1). The selection of hydrazine hydrate was importance as it facilitates easy handling and generates inert nitrogen gas as a sole byproduct.2224



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 14

Table 1: Catalyst screening and reaction optimizationa Catalyst, H2O NH2NH2.H2O Visible light

Entry

Catalyst

Time

Yieldb

1

Fe@g-C3N4 (1% Fe)

48h

34%

2

Fe@g-C3N4 (2% Fe)

24h

45%

3

Fe@g-C3N4 (5% Fe)

24h

85%

4

Fe@g-C3N4 (10% Fe)

8h

98%

5

Fe@g-C3N4 (20% Fe)

8h

95%

6

FeO

48h

5%

7

g-C3N4

48h

__

8c

Fe@g-C3N4 (10% Fe)

24h

13%

9

Fe3O4

48h

10d

Fe@g-C3N4 (10% Fe)

24h

5% __

a) Reaction conditions: Styrene (1mmol), catalyst (25 mg), NH2NH2.H2O (10 mmol), water (1.0 ml), 40 W domestic light bulb; b) Isolated yield; c) Reaction was performed in dark; d) Reaction was performed in water without hydrazine.

All reactions were performed using 1 mmol of styrene, 25 mg of Fe@g-C3N4 in water, and hydrazine hydrate under visible light irradiation. The percentage of iron played a crucial role in the development of photoactive magnetically separable Fe@g-C3N4 catalysts. The catalyst with 1% Fe (Table 1, entry 1) required 48 hours to produce 34 % of the desired product. The increase of iron loading to 2% increased the yield to 45% and reduced the reaction time to 24 hours (Table 1, entry 2). The Fe@g-C3N4 catalyst with a 5% loading afforded 85% of yield (Table 1, entry 3) but 10% of iron loading was very effective and gave the hydrogenated product in nearly quantitative yield (Table 1, entry 4; 98%). Further increase in the iron loading did not show any positive impact on the yield and the reaction time (Table 1, entry 5). Control experiment with


Page 5 of 14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


bare FeO nanoparticles under similar conditions produced a meager 5% conversion over the period of 48 hours (Table 1, entry 6). The hydrogenation using g-C3N4 as a catalyst under visible light did not generate any product after 48 hours of stirring (Table 1, entry 7). Immobilization of iron oxide over the g-C3N4 surface not only increased the activity of the catalyst, but also provided the activation energy through visible light absorption. The higher reaction rate may be attributed to synergetic effect of nano-ferrites and g-C3N4. After determining the active catalyst and optimum reaction conditions, the general reactivity and substrate scope was explored further. Thus, a wide range of alkenes and alkynes were subjected to hydrogenation conditions. Treatment of different styrene derivatives with Fe@g-C3N4 and NH2NH2.H2O under the optimized conditions led to the formation of corresponding hydrogenated products (Table 2, entries 1-10). The styrenes with electron-donating substituents underwent slow hydrogenation (Table 2, entries 2-3) compared to electron-withdrawing substituents on the similar substrates (Table 2, entries 4-5). The substituted alkenes, such as trans-stilbene and 1, 1-diphenylethylene, were efficiently hydrogenated using Fe@g-C3N4 under photochemical conditions (Table 2, entries 6-7). Hydrogenation of 1, 1-diphenylethylene (Table 2, entry 6) appeared to be faster than its isomer (Table 2, entry 7). The difference in reactivity of hydrogenation of stilbene and 1, 1-diphenylethylene could be accredited to their substituent patterns around double bonds. The aliphatic alkenes (Table 2, entries 8 -9) hydrogenated smoothly. The reaction of norbornene (Table 2, entry 9) was found to be much faster than cyclooctene (Table 2, entry 8). The higher rate of hydrogenation in the norbornene derivative is presumably due to its confirmation and stereo-chemical arrangement at bridge head positon. α, βunsaturated carbonyl compounds, such as chalcone, were selectively hydrogenated using Fe@gC3N4 under photochemical conditions (Table 2, entry 10). A wider scope and applicability of the catalyst system is explained by the hydrogenation of alkynes to corresponding alkanes under similar conditions using hydrazine hydrate as a source of hydrogen (Table 3, entries 1-3).



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 ACS Paragon Plus Environment

Page 6 of 14

Page 7 of 14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table 3: Hydrogenation of alkynes catalyzed by Fe@g-C3N4 a Entry

Reactant

Time

Product

Yieldb

1

12

95%

2

12

94%

3

10

97%

Cl

Cl

a) Reaction conditions: Alkyne (1.0 mmol), catalyst (25 mg), NH2NH2.H2O (20 mmol), H2O (1.0 ml), 40 W domestic light bulb; b) Isolated yield A plausible reaction mechanism based on the literature reports7 involves the coordination of hydrazine with nano-ferrites and the simultaneous activation of alkene through π-π stacking. The activation of hydrazine hydrogen and hydrogenation of double bonds may occur in a concerted process with inert nitrogen being the sole byproduct formed during the reaction, which escapes into the atmosphere (Figure 1). After demonstrating the general reactivity of the catalyst, it was important to study the

Figure 1 Plausible reaction mechanism for hydrogenation of alkene using Fe@g-C3N4



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

stability and recyclability aspects of the catalyst.

Hence, a set of experiments was

performed using 4-chlorostyrene as a substrate and the magnetic graphitic carbon nitride (Fe@g-C3N4) as a catalyst under photochemical conditions. As the reaction went to completion, the catalyst was separated magnetically, washed with acetone and dried at 50 °C. A new reaction was then setup using the recovered catalyst and fresh reactants. It was found that Fe@g-C3N4 could be recycled at least 10 times without losing its activity (ESI). The metal leaching of the Fe@g-C3N4 was studied using ICP-AES analysis. The iron concentration was found to be 9.97% before the reaction and 9.95 % after the 10th cycle of the reaction. The TEM and SEM images of the catalyst, recorded after the 10th cycle of the reaction, did not show a significant change in the morphology (ESI; S5 and S6) and nature of nanoparticles. The ICP-AES analysis of the mother liquor does show any traces of Fe, which confirms that g-C3N4 holds the iron ferrites tightly.

Conclusion An efficient and sustainable protocol has been developed for the hydrogenation of alkenes and alkynes using a magnetically separable photoactive catalyst that occurs efficiently at room temperature using aqueous hydrazine as a source of hydrogen. The Fe@g-C3N4 catalyst under photo chemical conditions has successfully eliminated the usage of high pressure hydrogen and enabled the reaction at room temperature. The high reactivity of the catalyst is attributed to non-covalent interactions between nano-ferrites and photoactive g-C3N4 surface.

ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website. XRD , TEM, SEM, EDX data of the catalyst Fe@g-C3N4; XRD, EDX data of support g-C3N4; TEM , SEM images of recycled catalyst Fe@g-C3N4 and 1H NMR of the products. AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected] Notes


Page 8 of 14

Page 9 of 14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


The authors declare no competing financial interest. Acknowledgements NBRB and SV were supported by the Postgraduate Research Program at the National Risk Management Research Laboratory administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the U.S. Environmental Protection Agency.

Disclaimer The views expressed in this article are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency. Any mention of trade names or commercial products does not constitute endorsement or recommendation for use.

Experimental Section Synthesis and characterization of catalyst The synthesis of catalyst, Fe@g-C3N4, involves two steps.16 First, the graphitic carbon nitride (g-C3N4) was synthesized by calcination of urea at 500 oC for 2 hours. The g-C3N4 was dispersed in a 10% solution of PEG in water using sonication. FeSO4.7H2O was added to this mixture and the stirring was continued for 8 hours. The excess of sodium borohydride was added thus reducing the FeSO4 to magnetic ferrites. Magnetic Fe@gC3N4 was separated using an external magnet, washed with water and methanol, and then dried under vacuum at 50 °C. The catalyst Fe@g-C3N4 was characterized by X-ray diffraction (ESI; S1), transmission electron microscopy (ESI; S2), scanning electron microscopy (ESI; S3), EDX (ESI; S4) and ICP-AES analysis.

General procedure for the hydrogenation of alkenes and alkynes The alkene/alkyne (1.0 mmol), NH2NH2.H2O (10 mmol/20 mmol for alkyne), and catalyst Fe@g-C3N4 (25 mg) were suspended in 1 mL of water. The reaction mixture was exposed to visible light using a 40 watt domestic light bulb. After the completion of the reaction, the catalyst was separated and recovered using an external magnet. The product was then extracted using CH2Cl2, dried over sodium sulfate, concentrated, and characterized.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 14

References 1. Roucoux, A.; Nowicki, A.; Philippot, K. Nanoparticles in Catalysis; Wiley-VCH, Weinheim 2008, 349-388. 2.

Roucoux, A.; Philippot, K. Handbook of Homogeneous Hydrogenation; Wiley-VCH, Weinheim 2007, 1,217-256.

3. Hudson, R.; Hamasaka, G.; Osako, T.; Yamada, Y. M. A.; Li, C. J.; Uozumi, Y.; Moores, A. Highly efficient iron(0) nanoparticle-catalyzed hydrogenation in water in flow. Green Chem. 2013, 15, 2141-2148. 4. Gartner, D.; Welther, A.; Rad, B. R.; Wolf, R.; Jacobi von Wangelin, A. Heteroatom-free arene-cobalt and arene-iron catalysts for hydrogenations. Angew. Chem., Int. Ed. 2014, 53, 3722-3726. 5.

Monfette, S.; Turner, Z. R.; Semproni, S. P.; Chirik, P. J.; Enantiopure C1-symmetric bis(imino)pyridine cobalt complexes for asymmetric alkene hydrogenation. J. Am. Chem. Soc. 2012, 134, 4561-4564.

6. Stein, M.; Wieland, J.; Steurer, P.; Tclle, F.; Mulhaupt, R.; Breit, B. Iron nanoparticles supported on chemically-derived graphene: catalytic hydrogenation with magnetic catalyst separation. Adv. Synth. Catal. 2011, 353, 523-527. 7. Mondal, J.; Nguyen, K. T. ; Jana, A.; Kurniawan, K.; Borah, P.; Zhao, Y. ; Bhaumik A. Efficient alkene hydrogenation over a magnetically recoverable and recyclable Fe3O4@GO nanocatalyst using hydrazine hydrate as the hydrogen source. Chem. Commun. 2014, 50, 12095-12097. 8. Chen, X.; Deng, D.; Pan, X.; Hu, Y.; Bao, X. N-doped graphene as an electron donor of iron catalysts for CO hydrogenation to light olefins. Chem. Commun. 2015, 51, 217-220. 9. Jagadeesh, R. V.; Natte, K.; Junge, H.; Beller, M. Nitrogen-doped graphene-activated iron-oxide-based nanocatalysts for selective transfer hydrogenation of nitroarenes. ACS Catal. 2015, 5, 1526-1529. 10. Nasir Baig, R. B.; Nadagouda, M. N.; Varma, R. S. Carbon-coated magnetic palladium: applications in partial oxidation of alcohols and coupling reactions. Green Chem. 2014, 16, 4333-4338. 11. Saha, A.; Nasir Baig, R. B.; Leazer, J.; Varma, R. S. A modular synthesis of dithiocarbamate pendant unnatural α-amino acids. Chem. Commun. 2012, 48, 8889-8891.


Page 11 of 14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


12. Varma, R. S. Journey on greener pathways: from the use of alternate energy inputs and benign reaction media to sustainable applications of nano-catalysts in synthesis and environmental remediation. Green Chem. 2014, 16, 2027-2041. 13. Verma, S.; Mungse, H. P.; Kumar, N.; Choudhary, S.; Jain, S. L.; Sain, B.; Khatri, O. P. Graphene oxide: an efficient and reusable carbocatalyst for aza-Michael addition of amines to activated alkenes. Chem. Commun. 2011, 47, 12673-12675. 14. Nasir Baig, R. B.; Varma, R. S. Magnetically retrievable catalysts for organic synthesis. Chem. Commun. 2013, 49, 752-770. 15. Nasir Baig, R. B.; Varma, R. S. Magnetic silica-supported palladium catalyst: synthesis of allyl aryl ethers in water. Industrial & Engineering Chemistry Research 2014, 53, 18625-18629. 16. Nasir Baig, R. B.; Nadagouda, M. N.; Varma, R. S. Magnetically retrievable catalysts for asymmetric synthesis. Coord. Chem. Rev. 2015, 287, 137-156. 17. Verma, S.; Verma, D.; Sinha, A. K.; Jain S. L. Palladium complex immobilized on graphene oxide-magnetic nanoparticle composites for ester synthesis by aerobic oxidative esterification of alcohols. Applied Catalysis A: General 2015, 489, 17-23. 18. Su, C.; Loh, K. P. Carbocatalysts: graphene oxide and its derivatives. Acc. Chem. Res. 2013, 46, 2275-2285. 19. Dong, F.; Wu, L.; Sun, Y.; Fu, M.; Wu, Z.; Lee, S. C. Efficient synthesis of polymeric gC3N4 layered materials as novel efficient visible light driven photocatalysts J. Mater. Chem. 2011, 21, 15171-15174. 20. Zhu, J.; Xiao, P.; Li, H.; Carabineiro, S. A. C. Graphitic carbon nitride: synthesis, properties, and applications in catalysis. ACS Appl. Mater. Interfaces 2014, 6, 1644916465. 21. Verma, S.; Nasir Baig, R. B.; Han, C.; Nadagouda, M. N.; Varma, R. S. Magnetic graphitic carbon nitride: its application in the C-H activation of amines. Chem. Commun. 2015, 51, 15554- 15557. 22. Ratnayake, W. M. N.; Grossert, J. S.; Ackman, R. Studies on the mechanism of the hydrazine reduction reaction: applications to selected monoethylenic, diethylenic and triethylenic fatty acids of cis configurations. J. Am. Oil Chem. Soc., 1990, 67, 940-946.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

23. Schmidt, E. W. Hydrazine and Its Derivatives: Preparation, Properties, and Applications. Wiley & Sons, New York, 2nd Edn. 2001, 1, 475. 24. Rai, R. K.; Mahata, A.; Mukhopadhyay, S.; Gupta, S.; Li, P. Z.; Nguyen, K. T.; Zhao, Y. L.; Pathak, B.; Singh, S. K. Room-temperature chemoselective reduction of nitro groups using non-noble metal nanocatalysts in water. Inorg. Chem. 2014, 53, 2904-2909.


Page 12 of 14

Page 13 of 14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


For Table of Contents Use Only

Magnetic Fe@g-C3N4: A Photoactive Catalyst for the Hydrogenation of Alkenes and Alkynes R. B. Nasir Baig b†, S. Verma a†, Rajender S. Varma a and Mallikarjuna N. Nadagouda b*

A photoactive catalyst, Fe@g-C3N4, has been developed for the hydrogenation of alkenes and alkynes using hydrazine hydrate as a source of hydrogen wherein the use of magnetically separable catalyst eliminates the use of high pressure in hydrogenation. The reaction can be accomplished under visible light without any external sources of energy.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Magnetic Fe@g-C3N4 a Photoactive Catalyst for the Hydrogenation of Alkenes and Alkynes 338x190mm (96 x 96 DPI)


Page 14 of 14

Magnetic Fe@g-C3N4: A Photoactive Catalyst for the Hydrogenation

Recommend Documents