Study on CO_2 Absorption by Aqueous Benzylamine and Its Formulations with Monoethanolamine as a Component for Post-Combustion Capture Process

Benzylamine(BZA) has been identified as a promising candidate for CO_2 capture process; however the evaluation of BZA in the packed column was very few. Thus, in this work, the absorption and regeneration performance of unblended BZA solvent as well as a series of amine concentrations and ratios in the formulations were studied using a semibatch bubbling reactor. And due to the formation of ivory-white precipitates in solvents containing higher BZA ratios, a 4:1 molar ratio of MEA/BZA mixed solvent was used to study its performance in a pilot-scale test bed. The results showed that a higher BZA ratio in the MEA/BZA mixed solvent resulted in a faster absorption rate, a higher mass transfer and heat transfer rate and a better cyclic performance, but the mass transfer rate of BZA decreased more quickly than MEA with the increase of CO_2 loading of the solvents. In addition, at high CO_2 loading in the MEA/ BZA mixed solvent with a molar ratio of 4:1, the ivory-white precipitates were generated which could cause blockage of the packing in the absorber, the stripper and the liquid pipelines.

Insights into spin polarization regulated exciton dissociation and charge separation of C_(3)N_(4)for efficient hydrogen evolution and simultaneous benzylamine oxidation

The employment of spin polarization under an external magnetic field holds great potential for the improvements of photocatalytic performance.However,owing to the huge difference in dielectric properties between ferromagnetic oxide and polymers,the photogenerated excitons with spin states are often limited to the ferromagnetic oxide wells,which leads to unsatisfactory activity.In this paper,a single-atom Co-doped C_(3)N_(4)photocatalyst is successfully synthesized for photocatalytic water splitting and simultaneous oxidation of benzylamine.Under a tiny external magnetic field(24.5 mT),the hydrogen production rate could reach at 3979.0μmol·g^(-1)·h^(-1),which is about 340 times that of C_(3)N_(4).Experimental results and theoretical calculations indicate that the interaction of Co d and N p orbital changes the symmetry center of C_(3)N_(4),resulting in an increase in dielectric constant and spin polarization.Moreover,magnetic fields further promote parallel electron spin,and the increased number of charges with the parallel spin-down state is likely to dissociate under the action of an external magnetic field.On the other hand,the Co-N bond provides a huge built-in electric field and active site for strengthening the charge transfer and surface reaction.This work not only deepens the understanding of spin polarization,but also enriches methods to accelerate electron-hole separation.

Boosting electrochemical hydrogen evolution by coupling anodically oxidative dehydrogenation of benzylamine to benzonitrile

The electricity-driven water splitting acts as a promising pathway for renewable energy conversion and storage, yet anodic oxygen evolution reaction(OER) largely hinders its efficiency. Seeking the alternatives to OER exhibits the competitive advance to address this predicament. In this work, we show a more thermodynamically and kinetically favorable reaction, electrochemical oxidative dehydrogenation(EODH)of benzylamine to replace the conventional OER, catalyzed by a cobalt cyclotetraphosphate(Co_(2)P_(4)O_(12)) nanorods catalyst grown on nickel foam. This anodic reaction lowers the electricity input of 317 mV toward the desired current density of 100 mA/cm^(2), together with a highly selective benzonitrile product of more than 97%. More specifically, when coupling it with cathodic hydrogen evolution reaction(HER),the proposed HER||benzylamine-EODH configuration only requires a cell voltage of 1.47 V@100 mA/cm^(2),exhibiting an energy-saving up to 17% relative to conventional water splitting, as well as the near unit selectivity toward cathodic H_(2) and anodic benzonitrile products.

Halogenated benzothiadiazole-based conjugated polymers as efficient photocatalysts for dye degradation and oxidative coupling of benzylamines

Donor-acceptor(D-A)conjugated polymers are widely used in photovoltaic applications and heteroge-neous catalysis due to their tunable building block and pre-designable structures.Here,a series of ad-justable Donor-acceptor(D-A)benzothiodiazole-based conjugated polymers were designed and synthe-sized.The photocatalytic performance could be improved by fine-tuning the chemical structure by halo-gen substitution(F or Cl).The polymers exhibited excellent optoelectronic properties and were effective photocatalysts for the degradation of RhB and MO dyes,as well as promoting the oxidative coupling of benzylamines.Complete degradation of RhB and MO occurred in 30 min under visible light radiation,while the yield of benzylamine coupling mediated by superoxide anion was as high as 82%.Systematic characterization methods were used to gain insights on the unique photocatalytic performance of the polymers.Our findings provide further insights into the design and synthesis of benzothiadiazole-based conjugated polymers as promising organic photocatalysts for solar energy conversion.

Determination of the acid dissociation constants of N-carboxymethyl-N-(p-hydroxy phenyl carbamoylmethyl)-2,3-dihydroxy- 5-carbomethoxy benzylamine and the stability constants of its metal complexes

The acid dissociation constants of N-carboxymethyl-N-(p-hydroxy phenyl carbamoyl- methyl)-2,3-dihydroxy-5-carbomethoxy benzylamine(CHDCB) and the stability constants of its 1:1 complexes with alkaline earth, Cd(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Fe(Ⅲ),Th(Ⅳ)and U(Ⅵ)ions have been determined at 25.0±0.1℃ and at an ionic strength of 0.1(KNO_3)by pH titration method. The probable coordination sites have also been discussed.

Diastereoselective alkylation of the (+)-ketopinic acid ketimine derived from benzylamine

Alkylation of the ketimine 2 obtained from condensation of (+)-ketopinic acid and benzyla- mine with a variety of alkylating agents gives the products whose trends in diastereomeric excesses (1- 100% O. P.) appear to correlate with the structure and reactivity of electrophilic agents. Using excess n-butyl lithium and allylic or benzylic halides, β-alkylation occured.

Asymmetric carbonyl addition with the homochiral ketimine derived from (+) or (-)-pinanone and benzylamine

The carbonyl addition of the pinanone ketimine derived from (+) or (-)-2-hydroxy-pinan- 3-one and benzylamine has been studied and the optically active α,β-substituted-β-aminoethanol deriva- tives were obtained in good chemical yields (36.5-69.5%) with optical purity ranging from 1.4% to 99.9%.

Primary amine coupling on nanocarbon catalysts: Reaction mechanism and kinetics via fluorescence probe analysis

Non-metallic nanocarbon materials catalyzed coupling reactions of primary amines to produce imine is an efficient,green and sustainable synthetic route,which has a wide application prospect in fine chemicals or pharmaceutical molecules.In the present study,we show firstly the relatively high catalytic activity of graphene oxide in the reaction of oxidative coupling of benzylamine(OCB),which is even comparable with typical metal-based catalysts,indicating the great potential of nanocarbon materials in this reaction system.More importantly,a novel twophoton fluorescence probe molecule(N-propyl-4-hydrazinyl-1,8-naphthalimide,NA)with special chemical structure of hydrazine functionality was synthesized.The probe NA could selectively react with aldehyde or ketone compounds,leading to the photoluminescence enhancement via inhibition of photo induced electron transfer(PET)process.The synthesized NA was applied as probe in carbon catalyzed OCB system to predict the existence of reaction intermediate benzaldehyde(BA),indicating the reaction pathway of oxidation-deamination-condensation in nanocarbon catalyzed OCB process.The proposed luminescence-probe strategy for revealing the kinetics and mechanism may also shed light in other reaction systems concerning the intermediates or products of ketones or aldehydes.

CO_(2)-adsorbent spongy electrode for non-aqueous Li–O_(2) batteries

Regulation of the Li_(2)CO_(3) byproduct is the most critical challenge in the field of non-aqueous Li–O_(2) batteries.Although considerable efforts have been devoted to preventing Li_(2)CO_(3) formation,no approaches have suggested the ultimate solution of utilizing the clean Li_(2)O_(2) reaction instead of that of Li_(2)CO_(3).Even if extremely pure O_(2) is used in a Li–O_(2) cell,its complete elimination is impossible,eventually generating CO_(2) gas during charge.In this paper,we present the new concept of a CO_(2)-adsorbent spongy electrode(CASE),which is designed to trap the evolved CO_(2) using adsorption materials.Various candidates composed of amine functional groups(–NH2)for capturing CO_(2) were screened,with quadrapurebenzylamine(QPBZA)exhibiting superior CO_(2)-adsorbing ability among the proposed candidates.Accordingly,we fabricated the CASE by sandwiching QPBZA between porous carbon layers,which facilitated the transport of gaseous products.The new electrode was demonstrated to effectively capture the evolved CO_(2) during charge,therefore altering the reaction pathways to the ideal case.It is highly advantageous to mitigate the undesirable CO_(2) incorporation in the next discharge,resulting in improved cyclability.This novel concept of a CO_(2)-sponging electrode provides an alternative route to the realization of practically meaningful Li–O_(2) batteries.

Synthesis,Structure and Oxidation Reaction of Tetrakis-pyridino-cobalt(Ⅱ) Dichromate

The title compound was prepared from the mixture of cobalt ( Ⅱ ) acetate, chromium trioxide and pyridine in an aqueous solution, and its structure was determined by X-ray single crystal diffraction method. A number of alcohols, benzyl halides and benzy-lamines can be oxidized by this oxidant to the corresponding aldehydes in high yields.

Improvement on the Synthesis of Primary Amino Sugar Derivatives <i>via</i><i>N</i>-Benzyl Intermediates

Primary tosylates 1a-d were converted to the corresponding amino species 3a-d. Benzylamine was proved effective for the substitution of tosylates, using acetonitrile (MeCN) as the solvent of choice and citric acid to remove excess of the reagent from crude products 2a-d. Debenzylation was carried out at circa (ca.) atmospheric pressure of hydrogen gas in the presence of acetic acid (AcOH). The method was also demonstrated in a demo batch experiment for the synthesis of compound 3a on a 50 g scale of 1a.

Porous S-doped carbon nitride foam with accelerated charge dynamics for synchronous photocatalytic hydrogen production and highly selective oxidation of amines

Photocatalytic hydrogen evolution coupled with organic oxidation holds great promise for converting solar energy into high-valueadded chemicals,but it is hampered by sluggish charge dynamics and limited redox potential.Herein,a porous S-doped carbon nitride(S-C_(3)N_(4−y))foam assembled from ultrathin nanosheets with rich nitrogen vacancies was synthesized using a molecular selfassembly strategy.The S dopants and N vacancies synergistically adjusted the band structure,facilitating light absorption and enhancing the oxidation ability.Moreover,the ultrathin nanosheets and porous structure provided more exposed active sites and facilitated mass and charge transfer.Consequently,S-C_(3)N_(4−y) foam exhibited enhanced photocatalytic activities for synchronous hydrogen evolution(4960μmol/(h·g))and benzylamine oxidation to N-benzylidenebenzylamine(4885μmol/(h·g))with high selectivity of>99%,which were approximately 17.6 and 72.9 times higher than those of bulk CN,respectively.The photocatalytic coupling pairing reaction promotes the water splitting by consuming H2O2,thereby improving the hydrogen evolution efficiency and achieving the production of high value-added imines.This study provides an effective route for regulating the morphology and band structure of carbon nitride for synthesizing highly valuable chemicals.

Covalent-organic frameworks with keto-enol tautomerism for efficient photocatalytic oxidative coupling of amines to imines under visible light

Photocatalytic oxidation of organic molecules into highly value-added products is an innovative and challenging research which has gradually attracted remarkable attention of scientists.In this work,it is demonstrated that the COF-TpPa with keto-enol tautomerism equilibrium structure shows excellent performance(yield>99%after 8 h)in the selective photocatalytic oxidative coupling of amines to imines under visible light irradiation.It is revealed that three kinds of reactive oxygen species(superoxide radical,hydroxyl radical and singlet oxygen)participate in this photocatalytic oxidation reaction.In addition,hydrogen protons cleaved from the benzyl are proven to be reduced to hydrogen in the conduction band of COF-TpPa in anaerobic atmosphere,accompanied with the formation of imines.The direct hydrogen evolution from amine provides an effective way to extract clean energy from organic molecule as well as the production of value-added chemicals.As a contrast,COF-LZU1 with similar structure and chemical composition to COF-TpPa but without keto-enol tautomerism exhibits worse optical properties and photocatalytic performance.It is also demonstrated that keto-enol tautomerism favors the adsorption of benzylamine based on the characterization results and theoretical calculations.

Visible-Light Photocatalytic and Photo-bactericidal Activity of Ni-CuWO_(4)/OTiO_(2) Composite

A series of nickel-doped copper tungstate/oxygen-rich TiO_(2) heterojunction-constructed composites of xNi-CuWO_(4)/OTiO_(2) were successfully prepared to demonstrate the enhancement of the visible-light photoactivity through promoting the photogenerated charge carrier separation efficiency.Of all these composites,0.2Ni-CuWO_(4)/OTiO_(2) exhibits excellent and stable visible light photoactivity for the photooxidative coupling of benzylamine to the corresponding N-benzyl-1-phenymethanimine(BPMI)in air atmosphere.The conversion of benzylamine and the selectivity to BPMI reach 97%and 99%,respectively.The catalyst shows good cyclability with the conversion of benzylamine decreasing just by 22%after being repeated six times with the well-maintained selectivity of BPMI.The composite also exhibits excellent photo-bactericidal ability,which greatly inhibits the reproducing of both the Gram-positive bacteria(e.g.,S.epidermidis)and Gram-negative bacteria(e.g.,E.coli).

Highly efficient photocatalytic dehydrogenative coupling of amines with supported platinum catalyst under the oxidant-free conditions

A highly efficient photocatalytic dehydrogenative coupling(PDC)of amines to prepare value-added imines has been developed under the mild conditions.A complete conversion of benzylamine with a 99%selectivity of Nbenzylidenebenzylamine could be obtained using the 2%Pt@g-C_(3)N_(4)as photocatalyst in the absence of hydrogen acceptor at room temperature.Moreover,the relationship between the physical properties of different photocatalysts and their activities has been discussed according to the characterization results of the XRD,BET,SEM,TEM,and XPS techniques.Next,the PDC of different amines have been further investigated,where ca.70.2%-99.0%yields of corresponding imines were attained.Finally,based on the experimental results and heterogeneous catalytic principle,a possible reaction mechanism for the PDC of benzylamine is proposed.