Catalytic transfer hydrogenation of bio-based furfural by palladium supported on nitrogen-doped porous carbon

Puthiaraj, Pillaiyar,Kim, Kyoungsoo,Ahn, Wha-Seung Elsevier 2019 CATALYSIS TODAY - Vol.324 No.-

<P><B>Abstract</B></P> <P>Highly porous carbon was prepared via a zeolite hard templating route. Subsequent melamine treatment produced nitrogen-functionalized carbon (NPC), which was used as a support to anchor Pd nanoparticles (Pd/NPC) of sizes 2–4 nm using the chemical reduction method. Various analytical techniques were used to characterize the textural properties, structure, and chemical nature of the catalyst. Pd/NPC was then employed as a catalyst for the transfer hydrogenation of biomass-derived furfural (FF) to furfuryl alcohol (FFA) with alcohol as a hydrogen donor, and the effect of temperature, hydrogen donor species, reaction time, and catalysts loading were investigated. The Pd/NPC catalyst was reusable up to five times without any apparent loss of its activity and selectivity. A possible mechanistic pathway for the catalytic transfer hydrogenation of FF over Pd/NPC catalyst was proposed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nitrogen-doped porous carbon (NPC) was produced via zeolite templating. </LI> <LI> Pd NPs with 2–4 nm sizes are incorporated on the NPC by chemical reduction. </LI> <LI> Pd/NPC showed good activity in the transfer hydrogenation of furfural using 2-butanol. </LI> <LI> Heterogeneous Pd/NPC catalyst was reusable up to five runs without decreases in activity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Triazine-based covalent organic polymers: design, synthesis and applications in heterogeneous catalysis

Puthiaraj, P.,Lee, Y. R.,Zhang, S.,Ahn, W. S. Royal Society of Chemistry 2016 Journal of materials chemistry. A, Materials for e Vol.4 No.42

<P>Triazine-based covalent organic polymers (COPs) constructed from triazine or nitrile containing precursors via covalent bonding are becoming an important sub-class of porous organic framework materials for a range of applications. In particular, these materials have been proposed as a new catalyst or support material for a variety of liquid phase organic transformation reactions owing to their tunable porous structures with high surface area, high nitrogen contents, high stability in both organic and aqueous media, and relatively easy synthesis. This review article summarizes the current research activities devoted to the synthesis and characterization of new triazine-based COP materials, and their applications for heterogeneous catalysis aiming at fine chemicals synthesis are presented with critical comments.</P>

Dual-functionalized porous organic polymer as reusable catalyst for one-pot cascade C C bond-forming reactions

Puthiaraj, Pillaiyar,Chung, Young-Min,Ahn, Wha-Seung Elsevier 2017 Molecular catalysis Vol.441 No.-

<P>A porous dual-functional acid-base covalent organic polymer catalyst (CBAP-1(EDA-SO3H)) was prepared using a facile Friedel-Crafts reaction of triphenylbenzene and terephthaloyl chloride to prepare the polymer backbone (CBAP-1) followed by functionalization with ethylenediamine (EDA) and a simple chlorosulfonic acid treatment. The resultant polymeric catalyst and its functional moieties were characterized by Fourier transform infrared (FTIR), elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and N-2 adsorption-desorption isotherm analyses. The catalytic activity of CBAP-1(EDA-SO3H) was then assessed for one-pot cascade C-C bond-forming reactions involving deacetylation-Knoevenagel condensation and Henry reactions. Compared with the homogeneous catalyst and CBAP-1 functionalized with just acid or base, CBAP-1(EDA-SO3H) showed superior catalytic activity and selectivity, and was found to be reusable for up to seven consecutive runs. A catalytic mechanism for C-C bond-forming reactions over CBAP-1(EDA-SO3H) was proposed. (C) 2017 Elsevier B.V. All rights reserved.</P>

CO₂ Capture by Porous Hyper-Cross-Linked Aromatic Polymers Synthesized Using Tetrahedral Precursors

Puthiaraj, Pillaiyar,Ahn, Wha-Seung American Chemical Society 2016 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.55 No.29

<P>Low-cost synthesis of porous hyper-cross-linked aromatic polymers (PHAPs) was achieved via the FeCl3-catalyzed Friedel-Crafts alkylation reaction between tetraphenylsilane or tetraphenylgermanium as a building block and formaldehyde dimethylacetal as a cross-linker. The synthesized polymers were chemically and thermally stable and exhibited high surface areas of up to 1137 m(2) (PHAP-1) and 1059 m(2) g(-1) (PHAP-2). The adsorption isotherms of the PHAPs revealed a high CO2 adsorption capacity (104.3-114.4 mg g(-1)) with an isosteric heat of adsorption in the range 26.5-27.3 kJ mol(-1) and a moderate CH4 adsorption capacity (12.6-13.8 mg g(-1)) at 273 K and 1 bar. The PHAP networks also exhibited high CO2/N-2 and CO2/CH4 relativities of 29.3-34.2 and 11.3-12.5, respectively, at 273 K.</P>

Ullmann coupling of aryl chlorides in water catalyzed by palladium nanoparticles supported on amine-grafted porous aromatic polymer

Puthiaraj, Pillaiyar,Ahn, Wha-Seung Elsevier 2017 Molecular catalysis Vol.437 No.-

<P>A chemically stable porous carbonyl-incorporated aromatic polymer (CBAP-1(EDA)) was post synthetically functionalized with ethylenediamine, and used as a solid support to immobilize the Pd nanoparticles (Pd@CBAP-1(EDA)) with particle size of 2-4 nm using conventional chemical reduction. The synthesized Pd@CBAP-1(EDA) was characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM), thermogravimetric analysis (TGA), N-2 adsorption-desorption isotherms, and inductively coupled plasma optical emission spectrometry (ICP-OES). The obtained material was tested as a solid catalyst for the environmentally-benign Ullmann self-coupling of aryl chlorides in water medium, showing excellent catalytic performance for a series of aryl chlorides without the addition of any external additives. The catalyst was easily recovered by simple filtration and could be reused six times without loss of its initial activity. The high catalyst stability was confirmed by hot filtration and ICP analysis. (C) 2017 Elsevier B.V. All rights reserved.</P>

Microporous covalent triazine polymers: efficient Friedel–Crafts synthesis and adsorption/storage of CO₂ and CH₄

Puthiaraj, Pillaiyar,Cho, Sung-Min,Lee, Yu-Ri,Ahn, Wha-Seung The Royal Society of Chemistry 2015 Journal of Materials Chemistry A Vol.3 No.13

<▼1><P>Microporous covalent triazine polymers were synthesized from inexpensive starting materials and their CO2 and CH4 gas uptakes were investigated.</P></▼1><▼2><P>Two kinds of microporous covalent triazine-based organic polymers (MCTPs) were synthesized from inexpensive starting materials <I>via</I> a simple and cost effective Friedel–Crafts reaction route, and their CO2 and CH4 gas uptake capacities were investigated. The synthesized microporous materials showed high BET surface areas of 1452 (MCTP-1) and 859 m<SUP>2</SUP> g<SUP>−1</SUP> (MCTP-2). MCTP-1 exhibited a significant CO2 uptake capacity (204.3 mg g<SUP>−1</SUP>, 273 K/1 bar) with moderate CO2/N2 selectivity (15.4), whereas MCTP-2 showed a moderate CO2 uptake capacity (160.6 mg g<SUP>−1</SUP>, 273 K/1 bar) but exceptional CO2/N2 selectivity (68.6). MCTP-1 also exhibited substantial CO2 (497.4 mg g<SUP>−1</SUP>) and CH4 (85.4 mg g<SUP>−1</SUP>) storage capacities at 300 K and 35 bar.</P></▼2>

Microporous amine-functionalized aromatic polymers and their carbonized products for CO₂ adsorption

Puthiaraj, Pillaiyar,Lee, Yu-Ri,Ahn, Wha-Seung Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.319 No.-

<P><B>Abstract</B></P> <P>Two porous aromatic polymers incorporated with carbonyl-functionality (CBAP-1 and CBAP-2) were synthesized via a Friedel-Crafts benzoylation reaction between 1,3,5-triphenylbenzene/biphenyl and terephthaloyl chloride/1,3,5-benzenetricarbonyl trichloride in the presence of anhydrous AlCl<SUB>3</SUB> as catalyst, and post-synthetically functionalized with ethylenediamine to obtain CBAP-1(EDA) and CBAP-2(EDA). The microporous carbon materials with BET surface areas up to 1063m<SUP>2</SUP> g<SUP>−1</SUP> were also prepared by carbonization of CBAP-1 and CBAP-1(EDA). After characterization using various analytical methods, these materials were tested as adsorbents for CO<SUB>2</SUB> and CH<SUB>4</SUB> capture at ambient conditions. High CO<SUB>2</SUB>/N<SUB>2</SUB> (97.2 and 87.8) and CO<SUB>2</SUB>/CH<SUB>4</SUB> (24.3 and 22.3) selectivities were observed for CBAP-1(EDA) and CBAP-2(EDA), respectively, at 273K/1bar, whereas the carbonized microporous materials exhibited high adsorption capacities for CO<SUB>2</SUB> (216.0–231.6mgg<SUP>−1</SUP>) and CH<SUB>4</SUB> (36.6–38.1mgg<SUP>−1</SUP>). This work demonstrates that post-synthesis functionalization of a porous aromatic polymer prepared by the simple Friedel-Crafts reaction can be an effective means to produce a family of host materials for effective gas adsorption.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cost-effective carbonyl-incorporated aromatic polymers (CBAPs) were synthesized. </LI> <LI> CBAPs were functionalized with ethylenediamine to obtain CBAPs (EDA). </LI> <LI> Microporous carbons were also prepared by carbonization of CBAPs and CBAPs (EDA). </LI> <LI> Prepared carbon materials exhibited high adsorption capacities for CO<SUB>2</SUB> and CH<SUB>4</SUB>. </LI> <LI> High CO<SUB>2</SUB> selectivities over N<SUB>2</SUB> and CH<SUB>4</SUB> were observed for CBAPs (EDA). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Facile synthesis of microporous carbonaceous materials derived from a covalent triazine polymer for CO2 capture

Puthiaraj, Pillaiyar,Ahn, Wha-Seung Elsevier Inc 2017 Journal of Energy Chemistry Vol.26 No.5

Pd nanoparticles on a dual acid-functionalized porous polymer for direct synthesis of H2O2: Contribution by enhanced H2 storage capacity

Pillaiyar Puthiaraj,Kwangsun Yu,Wha-Seung Ahn,정영민 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-

Direct synthesis of H2O2 from H2 and O2 can avoid the energy and environmental problems of currentmulti-step anthraquinone oxidation process by enabling high atom utilization and generating only awater by-product. However, the direct process suffers a low H2O2 yield, and it is challenging to suppressthe unfavorable side-reactions in the absence of corrosive additives under the restriction of explosionlimits. In this study, an efficient new catalyst was prepared by immobilizing Pd nanoparticles (NPs) on anacidic hyper-crosslinked porous polymer (HCPP). The Pd catalyst supported on HCPP functionalized withboth carboxylic and sulfonic acids (Pd/c-s-HCPP) achieved as high as 3130 mmol H2O2/g Pd.h with 82%selectivity to H2O2, which corresponded to one of the best catalysts reported so far. Pd/c-s-HCPP showedsuperior catalytic performance when compared with ones by Pd NPs supported on unfunctionalizedHCPP (Pd/HCPP), or sulfonated resin (Pd/SO3H-resin). Extensive characterizations and H2 adsorptionmeasurements indicated that the c-s-HCPP provided (i) selective adsorption sites for Pd precursors, (ii)acted as an efficient H2 reservoir in the proximity of the small Pd NPs formed, and (iii) imparts solidacidity to enhance H2O2 selectivity, which offered a new direction in the catalyst design for the directsynthesis of H2O2.

Cyclic carbonate synthesis from CO₂ and epoxides over diamine-functionalized porous organic frameworks

Ravi, Seenu,Puthiaraj, Pillaiyar,Ahn, Wha-Seung Elsevier 2017 Journal of CO₂ utilization Vol.21 No.-

<P><B>Abstract</B></P> <P>Porous aromatic polymers functionalized with ethylenediamine (CBAP-1(EDA)) and then complexed with Zn<SUP>2+</SUP> or Co<SUP>2+</SUP> ions (CBAP-1(EDA-Zn)) and (CBAP-1(EDA-Co) were synthesized and applied as a catalyst for the solventless synthesis of cyclic carbonates from CO<SUB>2</SUB> and epoxides. The properties of the catalysts were examined by various analytical techniques. CBAP-1(EDA) alone enabled the high catalytic conversion of epoxides (>98%) to five-membered cyclic carbonates at 130°C under solvent-, metal-, and co-catalyst-free conditions with high selectivity. The catalytic activity of CBAP-1(EDA) was enhanced in the presence of a nucleophile and Lewis acidic metal ion sites. Thus, CBAP-1(EDA) with tetrabutylammonium bromide (TBAB) had shown 98% conversion of epoxide at 80°C and 1MPa CO<SUB>2</SUB> in 8h, whereas CBAP-1(EDA-Zn) and CBAP-1(EDA-Co) with TBAB achieved 96% epoxide conversion in 36h at room temperature (RT). The stability of the catalysts was confirmed by hot-filtering and reusability tests, which demonstrated that the catalysts could be reused for up to five consecutive runs without any noticeable decline in catalytic activity. The synergism between the basic catalytic sites in CBAP-1(EDA) and TBAB and the Lewis metallic sites was explained by the proposed reaction mechanistic pathway covering both high temperature (metal- and halogen-free) and RT conditions (with metal and halogen).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Diamine-functionalized porous polymer and its Zn<SUP>2+</SUP>/Co<SUP>2+</SUP> complexed forms were prepared. </LI> <LI> These catalysts were applied for the CO<SUB>2</SUB> cycloaddition under mild reaction conditions. </LI> <LI> High activity, stability, and reusability of the catalysts were demonstrated. </LI> <LI> Mechanistic pathway was proposed covering different reaction temperature conditions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>