Ga-doped Cu/H-nanozeolite-Y catalyst for selective hydrogenation and hydrodeoxygenation of lignin-derived chemicals

Verma, Deepak,Insyani, Rizki,Cahyadi, Handi Setiadi,Park, Jaeyong,Kim, Seung Min,Cho, Jae Min,Bae, Jong Wook,Kim, Jaehoon The Royal Society of Chemistry 2018 Green chemistry Vol.20 No.14

<P>The development of an efficient non-sulfided and non-precious catalyst for selective hydrogenation (HD) and hydrodeoxygenation (HDO) of biomass-derived feedstocks to produce fuels and chemicals is of great interest. In this study, a highly efficient bimetallic Ga-doped Cu/H-nanozeolite-Y (Cu/HNZY) catalyst was developed for selective HD and HDO of lignin-derived species (vanillin, acetovanillone, and cinnamaldehyde) under mild conditions (120-180 °C, 1 MPa H2). The HNZY support exhibited a mesoporous structure with a large external surface area, which can facilitate reactant adsorption. Ga doping not only increased the Cu dispersion and Lewis acidity, but produced low coordinated Ga species (<I>e.g.</I>, Ga<SUP>+</SUP> and (GaH2)<SUP>+</SUP>), which could enhance the HDO activity. As a result, at 160 °C for 2 to 5 h, complete conversion of vanillin and acetovanillone into their decarbonylated species (creosol and 4-ethylguiuacol) with high selectivity (@@>@@99%) could be achieved at a low H2 initial pressure of 1 MPa. In addition, when cinnamaldehyde was converted over Ga-doped Cu/HNZY at 180 °C, selective HD and HDO followed by cyclization formed high amounts of indane and its derivatives, which have a variety of applications in pharmaceutical and agricultural industries. This could open a new possibility for lignin-to-drug intermediates.</P>

An Optimize Approach to Design MUX Based Decoder Using Source Coupled Logic

Pooja Verma,Deepak Punetha,Yogita Bahuguna 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.5

In Combination logic there are some patterns which commonly occur and it is convenient to represent these in their own separate units often they are also available as separate integrated circuits. This research paper covers the two of these, the decoder and the multiplexer. In this work, designing of 2:1 MUX and MUX Based Decoder using SCL (Source Coupled Logic) is done. Power and value of current spike (Rail–to-Rail current) is found for the circuits. The Simulation is done using 180nm technology using TANNER (Version 9.2) tool.

Analytical Design of Dual-Band and Wideband Balanced U-Shaped Power Divider

Jatoth Deepak Naik,Sweety Verma,Sandeep Kumar,AlaaDdin Al-Shidaifat,Hanjung Song 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.11

This design approach of power dividers for dual-band utilization without reactive elements. The stated circuit emphasizes structure by pragmatic impedance, distributed design with diminished parasitic effect, and accurate solution. In the mentioned approach, this dual-band operation, including arbitrary power division can be designed among an arbitrary-way power divider in a pure planar structure. Three-way power dividers obtain a newly developed recombinant system with a dual band. This arrangement contains a two-way dual-band power divider externally confinement structure. The entire scheme analytical equations and procedures of these suggested power dividers are exhibited. In theory, various three-way with dual-band and multiple power divisions are designed and simulated to validate our proposed design procedure operating at 0.5 GHz to 6 GHz. Traditional Transmission line-based inverters are employed to obtain a smaller circuit size. Wideband common-mode rejection is for the fundamental power divider structure with the two ideal 180° phase inverters employed as a substitute. Coupled-line sections and quarter-wavelength transmission lines are applied to concurrently apprehend the power bandpass filtering and wideband functionalities. Power divider manifests 3-dB of broadband for high in-band power, balanced to single-ended power division, band output-input power high-matching levels isolation levels among the wideband common-mode rejection, and two balanced outputs. The theoretical analysis, design method and parametric study as estimated single-ended differential-mode power dividers are presented.

Conformal carbon layer coating on well-dispersed Si nanoparticles on graphene oxide and the enhanced electrochemical performance

김초아,Deepak Verma,남동호,장원영,김재훈 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.52 No.-

Silicon nanoparticles (SiNPs)–graphene oxide (GO) composites are synthesized using a simple, fast, andmild ball-milling route. Uniform and conformal carbon layer is coated on the surface of SiNPs and thecarbon-coated SiNPs are well-dispersed on the GO matrix by forming Si O C linkages. A highreversible capacity of 1265 mA g 1 at 50 mA g 1 after 80 cycles, good rate capability of 238 mAh g 1 at2.5 A g 1, and long-term cyclability of 230 mAh g 1 at 1 A g 1 after 800 cycles are resulted. The mild ballmillingcan be highly promising and scalable approach for producing high-performance Si anodematerial.

One-pot di- and polysaccharides conversion to highly selective 2,5-dimethylfuran over Cu-Pd/Amino-functionalized Zr-based metal-organic framework (UiO-66(NH₂))@SGO tandem catalyst

Insyani, Rizki,Verma, Deepak,Cahyadi, Handi Setiadi,Kim, Seung Min,Kim, Seok Ki,Karanwal, Neha,Kim, Jaehoon Elsevier 2019 Applied Catalysis B Vol.243 No.-

<P><B>Abstract</B></P> <P>Tandem heterogenous catalysis of bimetallic Cu-Pd on UiO-66(NH<SUB>2</SUB>) that were incorporated into sulfonated graphene oxide (Cu-Pd/UiO-66(NH<SUB>2</SUB>)@SGO or Cu-Pd/US) was investigated for the one-pot, direct conversion of di- and polysaccharides into 2,5-dimethylfuran (2,5-DMF) without separation of reaction intermediates. In the absence of a homogeneous acidic catalyst, consecutive reactions of glycosidic bond cleavage, isomerization, dehydration, and hydrogenation/hydrogenolysis were preceded by the synergistic effect of a multifunctional Cu-Pd/US catalyst. The strength and ratio of Brønsted and Lewis acid sites by adjusting UiO-66(NH<SUB>2</SUB>) to SGO ratios resulted in high-yield 5-(hydroxymethyl)furfural (5-HMF) through sequential glycosidic bond cleavage, isomerization, and dehydration of sucrose. Unlike monometallic Cu and Pd, bimetallic Cu-Pd promoted consecutive COH hydrogenolysis and CO hydrogenation of reaction intermediates, producing 2,5-DMF with a high yield of 73.4% during the one-pot conversion of sucrose at 200 °C and 1 MPa H<SUB>2</SUB> for 3 h. When starch was converted over Cu-Pd/US, 2,5-DMF was formed with 53.6% yield. Direct cellulose conversion into 2,5-DMF with a yield of 29.8% was achieved in the presence of 0.01 M HCl and Cu-Pd/US. The presence of the amino functional group (-NH<SUB>2</SUB>) in the UiO-66 framework was beneficial for improving the feed conversion and maintaining catalyst recyclability up to five times with almost no activity loss.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cascade reactions from di- and polysaccharides to 2,5-DMF over CuPd/UiO-66(NH<SUB>2</SUB>)@SGO. </LI> <LI> Control of Brønsted and Lewis acid sites by adjusting UiO-66(NH<SUB>2</SUB>) to SGO ratio. </LI> <LI> Cu-Pd selectively promoted COH hydrogenolysis and CO hydrogenation of 5-HMF. </LI> <LI> One-pot sucrose conversion to 73.4% yield 2,5-DMF without intermediate purification. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Follicular Variant of Papillary Carcinoma Thyroid with Massive Angioinvasion of the Internal Jugular Vein: Our Approach

Roshan Kumar Verma,Deepak Sarahan,Gautamjeet Raj Kumar 대한갑상선학회 2020 International Journal of Thyroidology Vol.13 No.2

Follicular variant of papillary carcinoma thyroid is an aggressive variant of papillary carcinoma thyroid. It is morecommonly associated with extrathyroidal extension and regional lymphadenopathy. It can rarely be associated withmicroscopic vascular invasion but tumor thrombus into great veins is a rare phenomenon. We present a caseof 60-year-old male with follicular variant of papillary carcinoma thyroid with tumor thrombosis in superior thyroidvein and internal jugular vein (IJV). We report a case of a 60-year-old male who presented with a large swellingin the lower part of left side of neck for 4 months. Clinical examination revealed a hard swelling of 12x8 cmin left side of neck. Ultrasonography showed a solitary thyroid mass of the left lobe and a dilated left superiorthyroid vein and ipsilateral IJV. Fine-needle aspiration cytology revealed follicular variant of PTC cells. Totalthyroidectomy was done. A tumor thrombus was discovered in the superior thyroid vein and left IJV was foundto be dilated. The left IJV with superior thyroid vein was ligated and excised. The patient recovered well afterthe operation with no local or distant metastasis detected. Follicular variant of PTC commonly spreads to the lymphnodes. Vascular spread via direct intravascular extension through superior thyroid vein is extremely rare. Onpalpation cord like IJV is felt on the involved side. Neck ultrasound play important role in the diagnosis. Aggressivesurgical treatment with IJV ligation above and below the tumor thrombus is recommended to minimize the riskof potentially fatal complications of the intraluminal masses. Intravascular tumor extension into IJV of neck infollicular variant of PTC is rare and can be associated with serious consequences. Total thyroidectomy withthrombectomy with ligation of IJV must be done.

Conformal carbon layer coating on well-dispersed Si nanoparticles on graphene oxide and the enhanced electrochemical performance

Kim, Choa,Verma, Deepak,Ho Nam, Dong,Chang, Wonyoung,Kim, Jaehoon Elsevier 2017 Journal of industrial and engineering chemistry Vol.52 No.-

<P><B>Abstract</B></P> <P>Silicon nanoparticles (SiNPs)–graphene oxide (GO) composites are synthesized using a simple, fast, and mild ball-milling route. Uniform and conformal carbon layer is coated on the surface of SiNPs and the carbon-coated SiNPs are well-dispersed on the GO matrix by forming SiOC linkages. A high reversible capacity of 1265mAg<SUP>−1</SUP> at 50mAg<SUP>−1</SUP> after 80 cycles, good rate capability of 238mAhg<SUP>−1</SUP> at 2.5Ag<SUP>−1</SUP>, and long-term cyclability of 230mAhg<SUP>−1</SUP> at 1Ag<SUP>−1</SUP> after 800 cycles are resulted. The mild ball-milling can be highly promising and scalable approach for producing high-performance Si anode material.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A simple ball milling for Si nanoparticles (SiNPs) and graphene oxide composites. </LI> <LI> Formation of SiOC linkages between SiNPs and graphene oxide during ball milling. </LI> <LI> Uniform and conformal carbon layer is coated on the surface of SiNPs. </LI> <LI> A high capacity (1265mAhg<SUP>−1</SUP>) with a long-term cyclability (800 cycles) resulted. </LI> <LI> Batter electrochemical performance than SiNPs–RGO and SiNPs–graphite. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Solvothermal liquefaction of alkali lignin to obtain a high yield of aromatic monomers while suppressing solvent consumption

Riaz, Asim,Verma, Deepak,Zeb, Hassan,Lee, Jeong Hyeon,Kim, Jin Chul,Kwak, Sang Kyu,Kim, Jaehoon The Royal Society of Chemistry 2018 GREEN CHEMISTRY Vol.20 No.21

<P>The unique physicochemical properties and high solubility of a wide range of biomass-derived feedstocks make sub- and supercritical alcohols promising media for thermochemical conversion to liquid fuels and value-added chemicals. Short-chain alcohols (C1-C3) not only hydrogenolyse a variety of recalcitrant feedstocks by donating <I>in situ</I> hydrogen, but also suppress the char formation by capping reactive intermediates. However, the beneficial features of supercritical alcohols also bring some demerits, such as their excessive decomposition and high consumption, which has been given cursory attention to date. Consequently, the aim of this study was to elucidate the role of sub- and supercritical alcohols as a hydrogen donor, their self-reactivity, their reactivity with the feedstock, the extent of their conversion under catalytic and non-catalytic conditions, and the detailed pathways to byproduct formation. Based on the solvent reactivity, the optimum conditions were investigated for the solvothermal liquefaction of recalcitrant alkali lignin to give a high yield of aromatic monomers with careful emphasis on the solvent consumption. The addition of formic acid instead of the more commonly used hydrodeoxygenation catalysts (<I>e.g.</I>, CoMo/Al2O3, Ru/Al2O3) can not only suppress ethanol consumption significantly (from 42.3-46.8 wt% to 7 wt%), but can also result in complete lignin conversion by providing an excess amount of active hydrogen. The reaction at 350 °C for a short duration of 60 min led to the complete decomposition of alkali lignin and afforded a high yield of aromatic derivatives (36.7 wt%), while at the same time, suppressing ethanol consumption (11.8 wt%) and the formation of ethanol-derived liquid products. The alkylation of lignin-derived phenolic intermediates at the expense of the solvent is a time-dependent reaction, instead of the primary stabilization reaction. Molecular dynamics simulations using dilignol molecules revealed that the ethanol-formic acid mixture reduced the activation and thermal energies required for the dissociation of C-C and C-O bonds in the lignin structure.</P>

Excellent aging stability of upgraded fast pyrolysis bio-oil in supercritical ethanol

Jo, Heuntae,Verma, Deepak,Kim, Jaehoon Elsevier 2018 Fuel Vol.232 No.-

<P><B>Abstract</B></P> <P>The stabilities of low-boiling-fraction fast pyrolysis bio-oil (LBFBO) and upgraded bio-oil (UBO) produced using supercritical ethanol (scEtOH) were examined under accelerated aging conditions at 80 °C for up to 1 year. During the 3-month aging of LBFBO, a jelly-like non-flowable phase formed, and a hard, solid block formed after further aging for over 6 months. The viscosities and molecular weights of aged LBFBOs increased significantly. In contrast, the UBOs exhibited excellent stabilities after up to 6 months of aging with marginal increases in their viscosities and molecular weights. The condensation reaction during the aging of LBFBO led to the formation of water and reduced the oxygen content, while negligible changes were observed in the elemental contents of the aged UBOs. The excellent aging stability of UBO was attributed to its non- or less-reactive chemical species than those of LBFBO. Acetic acid, which acted as a catalyst for condensation and persisted for the 3-month aging of LBFBO, was converted into its corresponding ethyl ester during the scEtOH upgrading. The reactive pyrolytic lignin in LBFBO decomposed into its low-molecular-weight fractions. In addition, the other reactive species in LBFBO, such as aldehydes, furfural, and monoaromatics substituted with α,β-unsaturated aldehyde groups, were converted to less- or non-reactive species during the upgrading. Therefore, negligible compositional changes in the chemical structure of UBOs were achieved for up to 6 months of aging.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Accelerated aging for 1 year was tested before and after supercritical upgrading. </LI> <LI> Fast pyrolysis bio-oil (LBFBO) was upgraded in supercritical ethanol. </LI> <LI> Upgraded bio-oil (UBO) consisted of esters, alcohols, ethers and alkylated phenols. </LI> <LI> During the 3-month aging of LBFBO, a jelly-like non-flowable phase formed. </LI> <LI> Negligible compositional changes of UBO were achieved for up to 6 months of aging. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Highly-efficient and magnetically-separable ZnO/Co@N-CNTs catalyst for hydrodeoxygenation of lignin and its derived species under mild conditions

Ranaware, Virendra,Verma, Deepak,Insyani, Rizki,Riaz, Asim,Kim, Seung Min,Kim, Jaehoon The Royal Society of Chemistry 2019 GREEN CHEMISTRY Vol.21 No.5

<P>A catalyst comprising highly-efficient and magnetically-separable bimetallic ZnO and Co nanoparticles (NPs) deposited on N-doped carbon nanotubes (ZnO/Co@N-CNTs) was synthesized by the direct calcination of the bimetallic Zn/Co zeolitic imidazolate framework (Zn/Co-ZIF) for the effective hydrogenation (HD) and hydrodeoxygenation (HD) of lignin and its derived species. During the calcination of Zn/Co-ZIF, Zn was dislocated from the framework to the particle surface to form amorphous ZnO NPs and metallic Co NPs, which activated the growth of the N-CNTs. Because of the highly Lewis acidic amorphous ZnO, high HD/HDO ability of metallic Co NPs, and high wettability of the N-CNT, an almost complete conversion of vanillin into its corresponding deoxygenated species, creosol, was achieved in an aqueous medium without the production of byproducts under mild reaction conditions (150 °C, 0.7 MPa H2, a reaction time of 2 h). When kraft lignin and bio-oil derived from concentrated strong acid hydrolysis lignin were converted over ZnO/Co@N-CNTs, high degrees of deoxygenation of 74.2% and 34.4%, respectively, could be achieved at 350 °C, 5.0 MPa H2, and a reaction time of 6 h in water. A detailed chemical composition analysis of the deoxygenated bio-oil revealed that cyclohexanone and its alkyl group-substituted derivatives were the major species. To gain insight into the HD/HDO mechanisms, various types of lignin-derived monomers (syringaldehyde, acetovanillone, acetosyringone, 2-phenoxy-1-phenylethanol, cinnamaldehyde, isoeugenol) and holocellulose-derived monomers (furfural and 5-hydroxymethyl furfural), different types of catalysts, and various reaction parameters were tested. The mild reaction conditions, use of a non-noble metal catalyst, and use of water as the solvent make it possible to develop a cost-effective, easy to scale up, and environmental-benign process for biofuel and biochemical production.</P>