Vapor-Phase Transport Synthesis of MnSAPO-34 and Its Catalytic Properties

MnSAPO-34 molecular sieves were synthesized by vapor-phase transport （VPT） method using triethylamine （Et3N） as a structure directing agent （SDA）, and were characterized by XRD, BET, SEM, UV-Vis, FT-IR, and TG analy- ses. The influence of the zeolite crystallization conditions and the dry-gel composition were investigated. The results showed that the synthesis conditions had an effect on the crystalline phase. Pure MnSAPO-34 had been obtained when it was crystallized at 140 C for 18 hours. The ratio of MnO/A1203 in the starting gel ranging from 0.1 to 0.2 resulted in pure MnSAPO-34 with a CHA topology. Beyond this scope, MnSAPO-5 with an AFI topology structure was obtained as an impurity substance. UV-Vis spectroscopy and FT-IR spectroscopy study indicated that manganese was incorporated into the framework of the molecular sieve. The catalytic performance of MnSAPO-34 molecular sieve was tested by ketalization reaction of l, 2-propanediol with cyclohexanone. High yield of cyclohexanone-1, 2-propanediol ketal was obtained.

Synthesis of 4-Phenylphthalonitrile by Vapor-Phase Catalytic Ammoxidation of Intermediate 4-Phenyl-<i>o</i>-Tolunitrile: Reaction Kinetics

Kinetic regularities of 4-phenyl-o-tolunitrile ammoxidation on V-Sb-Bi-Zr/γ-Al2O3 oxide catalyst in the temperature interval 633 - 673 K have been studied. It has been established that rates of conversion of 4-phenyl-o-tolu- nitrile into the aimed 4-phenylphthalonitrile and CO2 are described by half-order equation on concentration of substratum and to be independent of the oxygen and ammonia partial pressures. It has been revealed that formation of 4-phenylphthalimide from byproducts is due to hydrolysis of 4-phenylphthalonitrile;carbon dioxide is produced by oxidation of 4-phenyl-o-tolunitrile and decarboxylation of 4-phenylphthalimide, and 4-phenylben- zonitrile is produced from 4-phenyl-o-tolunitrile and 4-phenylphthalimide.

Vapor-phase Nitration of Benzene to Nitrobenzene over Supported Sulfuric Acid Catalyst

Vapor-phase nitration of benzene over solid acid catalyst is expected to be a clean process with no sulfuric acid waste. We investigated this process over solid acidic catalysts utilizing diluted nitric acid (60-70%) as nitrating agent, and found that supported sulfuric acid catalyst exhibited a very high catalytic activity. Under the conditions of reaction temperature 160-170℃, space velocity (SV) 1200 h-1, the yield and the space-time yield (STY) of nitrobenzene (NB) based on HNO3 were more than 98% and 0.75 kg穔gcat-1穐-1 over 10% H2SO4/SiO2 (by weight) catalyst respectively.

Vapor-phase postsynthetic amination of hypercrosslinked polymers for efficient iodine capture

Hypercrosslinked polymers(HCPs)with large surface areas,high intrinsic porosities and low production costs may be available platforms for iodine capture.However,the lack of iodine-philicity binding sites limits their adsorption capacity.Here we use vapor-phase postsynthetic amination strategy to introduce electron-donating amino groups into the prefabricated HCPs for enhancing their iodine capture performance.Through simple vapor-phase exposure,the halogen-containing HCPs can be grafted by amines through nucleophilic substitution toward chloro groups.Combining with the abundant amino groups and high porosities,the amino-functionalized porous polymers show substantially increased iodine adsorption capacity,about 221%as that of original one,accompanied by excellent recyclability.Mechanism investigations reveal the key roles of the electron-donor amino groups andπ-conjugated benzene rings along with structure characteristics of porous polymer frameworks in iodine capture.Moreover,this vapor-phase amination strategy shows good generality and can be extended to various amines,e.g.,ethylenediamine,1,3-diaminopropane and diethylenetriamine.Our work proves that this simple vapor-phase postsynthetic functionalization strategy may be applied in other porous polymers with wide application prospects in adsorption,separation and storage.

Enhanced conductivity and stability of Prussian blue cathodes in sodium-ion batteries by surface vapor-phase molecular selfassembly

With many merits such as facile synthesis,economy,and relatively high theoretical capacity,Prussian blue analogs(PBAs)are considered promising cathode materials for sodium-ion batteries(SIBs).However,their practical applications still suffer from a low actual specific capacity and inferior stability owing to the imperfect crystallinity,irreversible phase transition,and low intrinsic conductivity.Herein,a surface-modification technique for vapor-phase molecular self-assembly was developed to prepare Fe-based PBAs,specifically sodium iron hexacyanoferrate(NaFeHCF),with a uniform conductive polymer protective layer of polypyrrole(PPy)on the surface,resulting in NaFeHCF@PPy.The incorporation of a PPy protective layer not only improves the electronic conductivity of NaFeHCF@PPy,but also effectively mitigates the dissolution of Fe-ions during cycling.Specifically,this advanced vapor-phase technique avoids Fe^(2+)oxidation and Na^(+)loss during liquid-phase surface modification.The NaFeHCF@PPy exhibited a remarkably enhanced cycling performance,with capacity retentions of 85.6%and 69.1%over 500 and 1000 cycles,respectively,at 200 mA/g,along with a superior rate performance up to 5 A/g(fast kinetics).Additionally,by adopting this strategy for Mn-based PBAs(NaMnHCF@PPy),we further demonstrated the universality of this method for PBA cathodes in SIBs.

Rational construction of multiple hollow silicalite-1 zeolite with enhanced quasi acidity for robust vapor-phase Beckmann rearrangement

Developing efficient and stable zeolites for vapor-phase Beckmann rearrangement of cyclohexanone oxime is still a great challenge to realizeε-caprolactam(CPL)green production.In this work,the hierarchical porous silicalite-1 zeolites with multiple hollow structure(S-1-M)are explored by in-situ desilication−recrystallization post-treatment of spongy highway-like zeolites(S-1-S),which are synthesized through silanization synthesis of conventional bulky silicalite-1(S-1).Compared to S-1,S-1-M achieves superior catalytic performance,with improving the CPL selectivity from 85.7%to 94.1%and prolonging the catalyst lifetime from 74 to 126 h at a weight hourly space velocity(WHSV)of 6 h^(−1).Comprehensive physiochemical studies demonstrate that the highly dispersed intracrystalline cavities within S-1-M endow greater mass diffusion and better quasi acidity inducing by the enhanced H-bonds among abundant H-bonded silanols,which is cooperatively responsible for its superior catalytic performance.

催化加氢转化CO_2的研究

研究催化加氢法转化ＣＯ２，在Ｆｅ／ＡＣ催化剂上采用不同的反应条件，可将ＣＯ２分别转化成低碳烯烃，液化石油气和液态烃，其转化率均在４０％－５０％之间。在Ｃｕ－Ｚｎ－分子筛催化剂上，３５％ＣＯ２可被转化成二甲醚；在Ｒｈ－Ｖ／ＳｉＯ２催化剂上，ＣＯ２可被转化成乙醇，其单程转化率在５％以上。

CuO-ZnO/ZrO_2催化剂上CO_2催化加氢合成甲醇的研究

采用并流共沉淀法制备了CO2加氢合成甲醇的CuO-ZnO/ZrO2催化剂,考察了反应温度、压力和空速等对催化剂性能的影响,并进行了催化剂活性稳定性评价。在原料气配比一定,CO2催化加氢合成甲醇较好的工艺条件为反应温度250℃,压力2.0MPa,空速1600h-1时,此时CO2转化率为23.1%,甲醇的选择性为50.2%。催化剂重复使用5次,CO2转化率仍在20%以上,催化剂活性稳定性较好。

六氟丙烷制备研究进展

综述了HFC-236fa和HFC-236ea的制备方法,认为气相氟化HCC-230制备HFC-236fa工艺和气相催化氢化六氟丙烯制备HFC-236ea工艺具有工业化应用前景。

催化加氢法制备3-氯-2-甲基苯胺

以2-氯-6-硝基甲苯为原料,经催化加氢还原制备3-氯-2-甲基苯胺。以W4型雷尼镍为催化剂,在助催化剂存在下研究了影响催化加氢反应的主要因素。在优化条件下,得到的产品纯度高于99%,收率高于95%。

1-氨丙基-2-甲基咪唑的合成与表征

以1-氰乙基-2-甲基咪唑(2MZCN)为原料催化氢化制备1-氨丙基-2-甲基咪唑,考察了反应过程中合成工艺参数对产物的影响,确定较为适宜的工艺条件为:温度100℃,压力5 MPa,转速624 r/min,时间4 h,溶剂是氨的饱和乙醇溶液(与原料质量比是2∶1),雷尼镍为催化剂(占原料质量的18.9%),氢氧化钾为助催化剂,原料的转化率可达99.7%,产率可达94.2%。采用红外光谱(FTIR)和核磁共振氢谱(1HNMR)及气质联用(GC-MS)对产物进行了表征。

β-(对甲氧基苯)乙胺的制备

以对甲氧基苯甲醛为原料经对甲氧基苯乙腈的高压催化氢化和β-硝基对甲氧基苯乙烯的还原两种途径合成β-(对甲氧基苯)乙胺。并改进了合成中间体的某些反应条件,收率有所提高。

顺式二氢茉莉酮酸甲酯的合成技术改进

以普通二氢茉莉酮酸甲酯为初始原料,N-溴代丁二酰亚胺作为溴代试剂,三乙胺为脱溴试剂,制得脱氢二氢茉莉酮酸甲酯;以Pd/C作催化剂,环己烷作溶剂,在温度为20℃,氢气压力为0.4 MPa下,脱氢二氢茉莉酮酸甲酯经催化氢化合成顺式二氢茉莉酮酸甲酯,经精馏得到的最终产品中顺式产品质量分数为35%。

Ir/C催化剂氯代硝基苯选择性催化加氢反应性能

采用浸渍法制备Ir/C和Pd/C催化剂,并用于氯代硝基苯选择性催化加氢反应,采用ICP-MS、XRD、XPS和TEM等手段对催化剂进行表征。结果表明,在相同负载量条件下,Ir在活性炭表面的分散与Pd有显著差异,Ir颗粒粒径更小且更均匀。在氯代硝基苯液相催化加氢反应中,Ir催化剂的催化活性较低,对氢解脱氯副反应有较好的抑制作用,这些性能与Ir的特殊性能有关。

非贵金属催化剂用于乳酸乙酯加氢制1,2-丙二醇

在间歇式反应釜考察了非责金属催化剂对乳酸乙酯液相加氢的催化性能,比较Ni、Cu、Co和Mo负载于γ-Al2O3的催化剂活性,研究添加Cr、Zn、Fe和Sn作为助剂的催化剂加氢效果.结果表明,Cu-Cr催化剂具有较佳的催化性能,n（Cu）∶ n（Cr） =2∶1时,催化剂活性最优.考察搅拌速率、催化剂粒径和催化剂用量对乳酸乙酯催化加氢的影响.在乙醇作溶剂、反应温度200℃、氢压3 MPa、搅拌速率900 r·min-1、底物浓度5 g·（100mL）-1、催化剂粒径（80～ 100）目和催化剂用量0.04 g·mL-1条件下,乳酸乙酯转化率和1,2-丙二醇选择性分别达到79.8％和80.1％.

Vapor-phase growth of high-quality wafer-scale two-dimensional materials

Emerging two-dimensional(2D)materials have stimulated tremendous scientific and industrial interests due to their diverse and tunable physical,chemical,and mechanical properties.The scalable production of high-quality wafer-scale 2D materials has become significantly essential to bring us closer to practical industrial applications,particularly in electronic devices.Vapor-phase growth provides attractive opportunities for the synthesis of large-area and high-quality 2D materials.In this review,we will emphasize vapor-phase growth strategies from three aspects,including suppressing nucleation,seamless stitching,and evolutionary selection growth.We discuss the general understanding of the related fundamental mechanism and specific parameter optimization from precursors and substrate design to the adjusting of growth parameters(temperature and pressure).Meanwhile,we present other strategies to produce various kinds of wafer-scale 2D materials.Finally,we conclude the current challenges and future directions in this developing field.This work may inspire researchers to better design routes in the synthesis of wafer-scale 2D materials with high quality.

催化氢化法合成4-乙酰氧基苯乙烯

以4-羟基苯乙酮为原料,经乙酰化、催化氢化和脱水反应,合成了化合物4-乙酰氧基苯乙烯,总收率为68.5%。用核磁共振氢谱、红外光谱对中间产物以及目标产物进行了结构表征。重点探讨和优化了催化氢化反应的工艺条件。结果表明,以占4-乙酰氧基苯乙酮质量10%的Raney-Ni为催化剂,在反应温度80℃、压力3 MPa、搅拌速度600 r/min、无水乙醇(每克4-乙酰氧基苯乙酮用4 mL无水乙醇)为溶剂的条件下进行催化氢化反应,4-乙酰氧基苯乙醇的收率可达83.1%;脱水反应采用全氟磺酸树脂作催化剂,4-乙酰氧基苯乙烯收率达85.0%。

Vapor-phase hydrothermal growth of single crystalline NiS2 nanostructure film on carbon fiber cloth for electrocatalytic oxidation of alcohols to ketones and simultaneous H2 evolution

Electrocatalytic synthesis of value-added chemicals is attracting significant research attention owing to its mild reaction conditions, environmental benignity, and potentially scalable application to organic synthetic chemistry. Herein, we report the preparation of a single-crystalline NiS2 nanostructure film of N 50 nm thickness grown directly on a carbon fiber doth （NiSJCFC） by a facile vapor-phase hydrothermal （VPH） method. NiSJCFC as an electrocatalyst exhibits activity for both the oxygen evolution reaction （OER） and the hydrogen evolution reaction （HER） in alkaline media. Furthermore, a series of alcohols （2-propanol, 2-butanol, 2-pentanol, and cyclohexanol） were electrocatalytically converted to the corresponding ketones with high selectivity, efficienc and durability using the NiSJCFC electrode in alkaline media. In the presence of 0.45 M alcohol, a remarkably decreased overpotential （- 150 mV, vs. RHE） at the NiS2/CFC anode compared with that for water oxidation to generate O2, i.e., the OER, in alkaline media leads to significantly improved H2 generation. For instance, the H2 generation rate in the presence of 0.45 M 2-propanol is almost 1.2-times of that obtained for pure water splitting, but in a system that employs an applied voltage at least 280 mV lower than that required for water splitting to achieve the same current density （20 mA-crn-2）. Thus, our results demonstrate the applicability of our bifunctional non-precious-metal electrocatalyst for organic synthesis and simultaneous H2 production.

Effects of Dislocation on High Temperature Transport Characteristics of Unintentionally Doped GaN

High temperature transport characteristics of unintentionally doped GaN have been investigated by means of high temperature Hall measurements from room temperature to 500^o C. The increment of electron concentration from room temperature to 500^o C is found to vary largely for different samples. The dispersion of temperature dependence of electron concentration is found to be directly proportional to the density of dislocations in GaN layers calculated by fitting the FWHM of the rocking curves in x-ray diffraction measurements （XRD）. The buildup levels in persistent photoconductivity （PPC） are also shown to be directly proportionM to the density of dislocations. The correlation of XRD, Hall and PPC results indicate that the high temperature dependence of electron density in unintentional doped GaN is directly dislocation related.

AlGaN-Based Solar-Blind Schottky Photodetectors Fabricated on AlN/Sapphire Template

We report AlGaN-based back-illuminated solar-blind Schottky-type ultraviolet photodetectors with the cutoff- wavelength from 280nm to 292nm without bias. The devices show low dark current of 2.1× 10^-6A/cm^2 at the reverse bias of 5 V. The specific detectivity D＊ is estimated to be 3.3 × 10^12cmHz^1/2 W^-1 . To guarantee the performance of the photodetectors, the optimization of AlGaN growth and annealing condition for Schottky contacts were performed. The results show that high-temperature annealing method for Ni/Pt Schottky contacts is effective for the reduction of leakage current.