Spongy acetylenic carbon material prepared by ball milling CaC2 and chlorinated rubber—Its mercury adsorption and electrochemical property

Design and preparation of novel advanced carbon materials with unique architecture and functional groups is of great significance.Herein,a spongy acetylenic carbon material(SACM) was prepared through mechanochemical reaction of CaC2 and chlorinated rubber in a planetary ball mill at ambient temperature.Its composition and structure were characterized,and its electrochemical properties and adsorption performance for Hg^2+ were studied.The SACM is composed of submicron spongy aggregates with high carbon content(81.8%) and specific area(503.9 m^2·g^-1),rich porosity and acetylenic groups.The SACM exhibits excellent adsorption for Hg2+with saturated adsorption amount being 157.1 mg·g^-1,which is superior to conventional carbon materials.Further,it exhibits good electrochemical performance with low equivalent series resistance(0.50 Ω),excellent cycling stability and ideal double layer capacitive behavior.This paper provides a novel and universal synthesis method of spongy carbon materials,and better results can be expected through tuning the pore structure,graphitization degree,and heteroatoms of the target carbon materials.

A Stereoselective Synthesis of Substituted Allyl Alcohol by Threecomponent Rection of Acetylenic Sulfone,Phenylselenomagnesium Bromide and Ketones

Phenylseleno and sulfonyl substituted allyl alcohols were synthesized stereoselectively by the three-component reaction of acetylenic sulfone, phenylselenomagnesium bromide and ketones in one-pot.

A one-pot stereoselective synthesis of 1,4-dienyl selenides by hydrostannylation-Stille tandem reaction of acetylenic selenides with Bu_3SnH and allylic bromides

1,4-Dienyl selenides can be stereoselectively synthesized in one pot under mild conditions in good yields by the palladiumcatalyzed hydrostannylation of acetylenic selenides, followed by Stille coupling with allylic bromides.

Synthesis of A New Kind of Acetylenic Polysilazane

A new kind of conjugated polymer, acetylenic polysilazane was prepared by ammono- lysis of acetylenic dimethylchlorosilane. The polymer was characterized by 29Si、13C NMR and elemental analysis.

THE STUDY OF COPOLYMERIZATION OF p-DIETHYNYLBENZENE WITH OTHER ACETYLENIC DERIVATIVES

The copotymerizations of p-diethynyibenzene(PDEB)with phenytacetylene(PHA),4,4'-diethynytbiphenyt (DEBP)or m-diethynylbenzene(MDEB)are studied in various mole ratios of monomers.The sotubitity pa- rameter(σ_p),swellabitity(θ_p),Huggins parameter(X),density (d_4^(25))and the average motecutar weights between crosstinksof obtained copotymers are measured.The IR spectra of these copolymers are recorded.The mechanism about the polymerization of acetytenic derivatives initiated by(Ph_3P)_2PdCl_2 is discussed.

Towards carbon neutrality of calcium carbide-based acetylene production with sustainable biomass resources

Acetylene is produced from the reaction between calcium carbide(CaC_(2))and water,while the production of CaC_(2) generates significant amount of carbon dioxide not only because it is an energy-intensive process but also the raw material for CaC_(2) synthesis is from coal.Here,a comprehensive biomass-to-acetylene process was constructed that integrated several units including biomass pyrolysis,oxygen-thermal CaC_(2) fabrication and calcium looping.For comparison,a coal-to-acetylene process was also established by using coal as feedstock.The carbon efficiency,energy efficiency and environmental impacts of the bio-based calcium carbide acetylene(BCCA)and coal-based calcium carbide acetylene(CCCA)processes were systematically analyzed.Moreover,the environmental impacts were further evaluated by applying thermal integration at system level and energy substitution in CaC_(2) furnace.Even though the BCCA process showed lower carbon efficiency and energy efficiency than that of the CCCA process,life cycle assessment demonstrated the BCCA(1.873 kgCO_(2eq) kg-prod^(-1))a lower carbon footprint process which is 0.366 kgCO_(2eq) kg-prod^(-1) lower compared to the CCCA process.With sustainable energy(biomass power)substitution in CaC_(2) furnace,an even lower GWP value of 1.377 kgCO_(2eq) kg-prod^(-1) can be achieved in BCCA process.This work performed a systematic analysis on integrating biomass into industrial acetylene production,and revealed the positive role of biomass as raw material(carbon)and energy supplier.

One-pot synthesis of pyrrolo[1,2-a]pyrazines via three component reaction of ethylenediamine,acetylenic esters and nitrostyrene derivatives

An effective route to pyrrolo[1,2-a]pyrazines is described via reaction of ethylenediamine,acetylenic esters and nitrostyrene derivatives in the presence of 20 mol%of sulfamic acid.

Towards the insights into the deactivation behavior of acetylene hydrogenation catalyst

A series of model catalysts were obtained by treating commercial fresh and spent catalysts unloaded from the factory with different methods, including green oil dipping, extraction and high-temperature regeneration;finally, the deactivation behavior of the commercial catalyst for acetylene hydrogenation were studied. The influence of various possible deactivation factors on the catalytic performance was elucidated via detailed structural characterization, surface composition analysis, and activity evaluation.The results showed that green oil, carbon deposit and sintering of active metal were the main reasons for deactivation, among which green oil and carbon deposit led to rapid deactivation, while the activity could be recovered after regeneration by high-temperature calcination. The sintering of active metal components was attributed to the high-temperature regeneration in hydrothermal conditions, which was slow but irreversible and accounted for permanent deactivation. Thus, optimizing the regeneration is expected to extend the service life of the commercial catalyst.

One-pot synthesis of novel pyrrolo-1,4-benzoxazines via a three- component reaction of 2-amino phenols, acetylenic esters and nitrostyrene derivatives

A simple and efficient synthetic protocol has been developed using a one-pot, three-component reaction involving 2-amino phenols, dialkyl acetylene dicarboxylates and nitrostyrene derivatives. Utilizing this protocol, a variety of novel pyrrolo-1,4-benzoxazine derivatives were synthesized in excellent yields.

Chemoselective synthesis of novel aminoindolizines using aminopyridines, acetylenic diesters and α-halo ketones

A chemoselective synthesis of novel indolizine derivatives were reported via three-component reactions of aminopyridines, acetylenic diesters and a-halo ketones. In these reactions, the zwitterion generated from aminopyridines and acetylenic diesters reacted with a-halo ketones to produce indolizine skeleton in good to high yields under mild reaction conditions.

Photochemistry of heterocycles——VIII. photocycloaddition of acetylenic compounds to 1,3-dimethyl-6-azathymine

The photocycloadditions of 1,3-dimethyl-6-azathymine to 2-butyne-1,4-diol and 1,4-di- methoxyl-2-butyne have been studied. Three novel compounds, 7,8-bis(hydroxymethyl)-3,5-dioxo-2,4, 6-trimethyl-1,2,4-triazabicyclo [4,2,0]-7-octene (1), 7,8-bismethoxymethy1-3,5-dioxo-2,4,6-trimethyl- 1,2,4-triazabicyclo[4,2,0]-7-octene (2) and 8,9-bismethoxymethy1-4-oxo-1,3,5-trimethyl-7-oxa-2,3,5- triazaspiro[5,3]-1,8-nonadiene (3) were obtained. The proposed reaction mechanism, which includes excited triplet complexes and biradicals as intermediates, was supported by kinetic ana photophysical studies.

Electron-deficient Cu site catalyzed acetylene hydrochlorination

Rational design of catalytic sites to activate the C≡C bond is of paramount importance to advance acetylene hydrochlorination. Herein, Cu sites with electron-rich and electron-deficient states were constructed by controlling the impregnation solutions. The π electrons flowing from acetylene to Cu site are facilitated over the electron-deficient Cu sites, achieving high activation of C≡C bond. The contradiction between the increased activation of acetylene required for enhanced catalytic activity and the resistance of Cu site to reduction by acetylene required for maintaining catalytic stability can be balanced by establishing strong interactions of Cu site with pyrrolic-N species. The catalytic activity displays a volcano shape scaling relationship as a function of Cu particle size. Tribasic copper chloride is concomitantly generated with the construction of electron-deficient Cu sites. The H–Cl bond of HCl can be activated over the tribasic copper chloride, accelerating the surface reaction of vinyl chloride production. This strategy of inducing electron deficiency provides new insight into the rational design of catalysts for the synthesis of vinyl chloride with a high catalytic performance.

Regulating the coordination environment of Ru single-atom catalysts and unravelling the reaction path of acetylene hydrochlorination

In this work,DFT calculations were used firstly to simulate the nitrogen coordinated metal single-atom catalysts(M-N_(x)SACs,M=Hg,Cu,Au,and Ru) to predict their catalytic activities in acetylene hydrochlorination.The DFT results showed that Ru-N_(x)SACs had the best catalytic performance among the four catalysts,and Ru-N_(x)SACs could effectively inhibit the reduction of ruthenium cation.To verify the DFT results,Ru-N_(x)SACs were fabricated by pyrolyzing MOFs in-situ spatially confined metal precursors.The N coordination environment could be controlled by changing the pyrolysis temperature.Catalytic performance tests indicated that low N coordination number(Ru-N_(2),Ru-N_(3))exhibited excellent catalytic activity and stability compared to RuCl_(3)catalyst.DFT calculations further revealed that Ru-N_(2)and Ru-N_(3)had a tendency to activate HCl at the first step of reaction,whereas Ru-N4tended to activate C_(2)H_(2).These findings will serve as a reference for the design and control of metal active sites.

Nitrogen and phosphorus co-doped activated carbon induces high density Cu^(+)active center for acetylene hydrochlorination

This work aims to solve the problems of low reaction activity of Cu-based catalysts and agglomeration of active centers in acetylene hydrochlorination.Cu-based catalysts supported by NAP co-doped activated carbon(AC)with different content(mCu-xNP/AC)were manufactured and applied in the acetylene hydrochlorination reaction.It was found that the doping of carriers N and P induced the transformation of Cu^(2+)to Cu^(+),and the catalytic activity was markedly improved.Under the optimal reaction temperature of 220℃,the gas hourly space velocity(GHSV)of C_(2)H_(2)was 90 h^(-1)and V_(HCl):V_(C_(2)H_(2))was 1.15.The initial activity of the 5%Cu-30 NP/AC catalyst reached 95.59%.Through some characterization methods showed the addition of N and P improved the dispersion of Cu in carbon,which increased the ratio of Cu^+/Cu^(2+).The measurement results confirmed that the chemisorption capacity of mCu-xNP/AC for C_(2)H_(2)decreased slightly,and the chemisorption capacity for HCl increased significantly,which was the reason for the increased activity of the catalyst.The conclusion provides a reference for the development of acetylene hydrochlorination Cu catalyst.

Effect of gas flow on the nanoparticles transport in dusty acetylene plasmas

This article presents simulation results on the effects of neutral gas flow for nanoparticle transport in atmospheric-pressure,radio-frequency,capacitively-coupled,and acetylene discharge.The acetylene gas is set to flow into the chamber from the upper showerhead electrode.The internal energy of the gas medium therein is transferred into kinetic energy so the gas advection can be triggered.This is represented by the pressure volume work term of the gas energy converse equation.The gas advection leads to the gas temperature sink at the gas inlet,hence a large gas temperature gradient is formed.The thermophoresis relies on the gas temperature gradient,and causes the profile of nanoparticle density to vary from a double-peak structure to a single-peak one.The gas advection influences the properties of electron density and temperature as well and causes the drift-ambipolar mode profile of electron density asymmetric.In the bulk region,i.e.away from the inlet,the gas advection is more like one isovolumetric compression,which slightly increases the temperature of the gas medium at consuming its kinetic energy.

An efficient method for synthesis of organophosphorus compounds in aqueous media

A convenient and facile one-pot synthesis of stable phosphorus ylides and 1,4-diionic organophosphorus compounds is reported by the reaction of triphenylphosphine, dialkylacetylenedicarboxylates and N-H, C-H or S-H acids in the presence of polyethyleneglycol （PEG）, β-cyclodextrin （β-CD）, glycerine （Gly） or ethyleneglycol （EG） in water. This methodology is of interest due to the use of water as a solvent, thus minimizing the cost operational hazards, and environmental pollution.

Nitrous oxide emission and reduction in a laboratory-incubated paddy soil response to pretreatment of water regime

A laboratory incubation experiment was conducted to investigate nitrous oxide(N 2O) emission and reduction in a paddy soil(Stagnic Anthrosol) response to the pretreatment of water regime. The paddy soil was maintained under either air dried(sample D) or submerged(sample F) conditions for 110 d before the soil was adjusted into soil moisture of 20%, 40%, 60%, 80% and 100% water holding capacity(WHC) respectively, and then incubated with or without 10%(v/v) acetylene for 138 h at 25℃. At lower soil water content (≤60% WHC), N 2O emission from the sample F was 2 29 times higher than that from the sample D( P <0 01). While, N 2O emission from the sample F was only 29 and 14 percent of that from the sample D at the soil moisture of 80% and 100% WHC, respectively( P <0 01). The maximal N 2O emissions observed at soil moisture of 80% WHC were about 24 and 186 times higher than the minima obtained at the soil moisture of 20% WHC for the sample F and D, respectively. But at the soil moisture of 80% and 100% WHC, N 2O emission from the sample F with acetylene(F+ACE) was comparable to that of the sample D with acetylene (D+ACE). The results showed that the F sample produced N 2O ability in denitrification was similar to the sample D, however, the sample F was in the better reduction of N 2O to N 2 than the sample D even after the soil moisture was adjusted into the same level of 80% or 100% WHC. Therefore, the pretreatment of water regime influenced the strength and product composition of denitrification and N 2O emission from the paddy soil.

Nitrogen doped carbon catalyzing acetylene conversion to vinyl chloride

Commercial production of vinyl chloride from acetylene relies on the use of HgCla as the catalyst, which has caused severe environmental problem and threats to human health because of its toxicity. Therefore, it is vital to explore alternative catalysts without mercury. We report here that N-doped carbon can catalyze directly transformation of acetylene to vinyl chloride. Particularly, N-doped high surface area mesoporous carbon exhibits a rather high activity with the acetylene conversion reaching 77% and vinyl chloride selectivity above 98% at a space velocity of 1.0 mL.min-l.g-1 and 200 ~C. It delivers a stable performa℃nce within a test period of 100h and no obvious deactivation is observed, demonstrating potentials to substitute the notoriously toxic mercuric chloride catalyst.

Stability improvement of the Nieuwland catalyst in the dimerization of acetylene to monovinylacetylene

In the process of dimerization of acetylene to produce monovinylacetylene （MVA）,the loss of active component CuCl in the Nieuwland catalyst due to the formation of a dark red precipitate was investigated.The formula of the precipitate was CuCl·2C2H2·1/5NH 3,and it was presumed to be formed by the combination of NH 3,C2H2 and [Cu]-acetylene π-complex,which was an intermediate in the dimerization reaction.The addition of hydrochloric acid into the catalyst can reduce the formation of precipitate,whereas excessive H＋ is unfavorable to the dimerization reaction of acetylene.To balance between high acetylene conversion and low loss rate of CuCl,the optimum mass percentage of HCl in the added hydrochloric acid was determined.The result showed the optimum mass percentage of HCl decreased from 5.0% to 3.2% when the space velocity of acetylene was from 140 h-1 to 360 h-1.The result in this work also indicated the pH of the Nieuwland catalyst should be kept in the range of 5.80-5.97 during the reaction process,which was good for both catalyst life and acetylene conversion.

Selective hydrogenation of acetylene on SiO_2-supported Ni-Ga alloy and intermetallic compound

Ni/Si O_2 and bimetallic Ni_xGa/SiO_2 catalysts with different Ni/Ga atomic ratios(x = 10～2) were investigated for the selective hydrogenation of acetylene.It was found that Ni_xGa/SiO_2 showed higher selectivity to ethylene than Ni/Si O_2.This is attributed to the formation Ni-Ga alloy and Ni3 Ga intermetallic compound(IMC) where there was a charge transfer from Ga to Ni,which is favorable for reducing the adsorption strength and amount of ethylene on Ni atoms.As a result,the over-hydrogenation,the C–C bond hydrogenolysis and the polymerization were suppressed,and subsequently the selectivity to ethylene was enhanced.With the decrease of Ni/Ga atomic ratio,the activity and stability of the Ni_xGa/SiO_2 catalysts increased first and then decreased,while the ethylene selectivity tended to increase.Ni_5 Ga/SiO_2 exhibited the best performance.Under the conditions of 180 °C,0.1 MPa,and a reactant(1.0 vol% acetylene,5.0 vol% H_2 and 94 vol% N_2) with the space velocity of 36,000 m L h^(-1) g^(-1),the acetylene conversion maintained at 100% on Ni_5 Ga/SiO_2 during 120 h time on stream and the selectivity to ethylene was 75%～81%after reaction for 68 h.It was also found that the formation of Ni-Ga alloy and Ni_3 Ga IMC suppressed the incorporation of carbon to form NiCx,subsequently enhancing the catalyst stability.Additionally,with increasing the Ga content,the catalyst acid amount and strength tended to increase,which promoted the polymerization and carbon deposition and so the catalyst deactivation.