脱硫脱硝后V2O5/AC在含NH3气氛中的再生及硫资源化的耦合过程研究

V2O5/AC具有很好的烟气同时脱硫脱硝能力,脱硫过程包括其对烟气中SO2的吸附、吸附饱和后SO2从其上的脱附（再生）及脱附出SO2的资源化。考察了同时脱硫脱硝后的V2O5/AC在含NH3气氛中的再生和硫资源化的耦合过程。研究了NH3注入量、再生温度、再生时间和尾气循环流量对再生效率、硫回收率及二次脱硫脱硝活性的影响。结果表明,再生温度和再生时间主要影响SO2的脱附,因而影响再生效率和二次脱硫脱硝活性;NH3注入量不影响SO2的脱附,但明显影响硫回收率和二次脱硫脱硝活性;尾气循环模式是提高硫回收率的重要方法,但在研究的条件下循环流量对再生效率、硫回收率和二次脱硫脱硝活性的影响不大。     

过渡金属氧化物催化剂上NH3 分解Claus反应机理研究

运用浸渍法制备了七种过渡金属氧化物催化剂.对于NH3 分解反应均可获得很高的NH3转化率;对于NH3分解Claus反应则可以获得较高的SO2转化率和单质硫选择性.通过比较发现Co3O4-TiO2和Fe2O3-TiO2催化剂的低温活性比较高.经过XRD表征发现,在NH3分解Claus反应中,催化剂的活性相可能是过渡金属硫化物.结合活性评价和XRD表征结果提出了NH3分解Claus反应的机理.     

Al2（SO4）3／SiO2催化甲醇脱水合成二甲醚

采用浸渍法制备了不同负载量的Al2（SO4）3／SiO2催化剂．使用BET、XRD、FT—IR、异丙醇探针反应、NH3吸附量热和NH3吸附红外等手段对催化剂进行了表征,并测试了其在甲醇脱水合成二甲醚反应中的活性．BET、XRD和FT-IR结果表明,载体SiO2的表面积较高,随着Al2（SO4）3负载量的增加,样品的表面积逐渐降低,当Al2（SO4）3负载量高于20％时,样品表面开始出现晶相Al2（SO4）3．NH3吸附量热和NH3吸附红外结果表明,载体SiO2的酸性很弱,负载了Al2（SO4）3后,样品酸性大大增强,且酸性随着Al2（SO4）3负载量的增加先增强后减弱．样品表面同时存在B酸中心和L酸中心,但以B酸中心为主．Al2（SO4）3负载量为3％的样品的表面酸性最强,因而在甲醇脱水反应中表现出最高的反应活性,533K,甲醇转化率为83．5％,二甲醚选择性100％．     

用CuO／γ－Al2O3催化剂同时脱除烟气中的SO2和NO

 研究了用CuO／γ－Al2O3催化剂同时脱除烟气中的SO2和NO，并在固定床反应器中考察了反应条件对其催化活性的影响．结果表明，温度和SO2对CuO／γ－Al2O3的催化活性均具有双重影响．新鲜催化剂和硫化催化剂上最适宜的脱硝温度分别为250～300℃和300～450℃，最适宜的n（NH3）／n（NO）约为1．2．烟气中的氧可大大提高CuO／γ－Al2O3的脱硫脱硝活性．综合考虑吸附硫容和NO脱除率，CuO／γ－Al2O3同时脱硫脱硝的最适宜温度为350～450℃．温度和SO2在高温区对CuO／γ－Al2O3活性的影响源于两者对NH3氧化活性的改变，高温下CuO／γ－Al2O3的活性下降是因为NH3氧化加剧；SO2通过使催化剂硫化生成硫酸盐来抑制NH3氧化，从而提高CuO／γ－Al2O3的活性．吸硫饱和的催化剂可于5％NH3中还原再生，再生后其硫容较初始时降低，但其活性大幅度提高．     

再生方法对V2O5/AC催化剂同时脱硫脱硝活性的影响

 考察了水洗再生、Ar热再生和5%NH3-95%Ar还原再生对V2O5/AC催化剂同时脱硫脱硝活性的影响. 结果表明,水洗再生虽然可洗去反应过程中沉积在催化剂表面的含硫物质,但也能将部分活性组分V2O5转化生成的VOSO4洗去,使催化剂的脱硫脱硝活性降低. Ar热再生后催化剂的脱硝活性与新鲜样品相同,但脱硫活性很低. 经5%NH3-95%Ar还原再生后,催化剂的脱硫活性可恢复到新制备时的水平,同时脱硝活性大大提高,这是由于催化剂表面除了原有的脱硝活性位V2O5外,又形成了新的活性位NH+4/NH-2. 还原再生过程产生的SO2与NH3在室温下反应生成固体亚硫酸铵盐,可实现硫的资源化,简化了后续处理工艺.     

流化床快速制不定形活性焦脱除烟气中SO2的研究

利用大型流化床制得了适用于脱除烟道气中二氧化硫的不定形活性焦AC-A,并对其进行了特性分析,在固定床上考察了不同条件下脱除SO2的性能。与硫容相近的商业活性焦AC-B的脱硫性能对比,发现其脱硫性能较好。实验结果表明,在烟气中的二氧化硫的体积分数为0.05%~0.12%,反应温度为80 ℃～100 ℃,空速（GHSV）为1 200 h-1,O2的体积分数为6%,水蒸气为10%的情况下,活性焦AC-A保持SO2脱除率在90%以上达5 h。再生循环脱硫实验表明,活性焦AC-A具有良好的再生脱硫活性。     

同时脱除烟气中硫和硝的V2O5/AC催化剂研究

通过在固定床微反应器上对同时脱硫脱硝催化剂的研究,发现将V2O5担载在活性焦(AC)上制得的V2O5/AC催化剂可在200 ℃同时脱除烟气中的SO2和NO,其活性明显高于纯AC。V2O5/AC催化剂的脱硫脱硝活性与催化剂中钒的质量分数有关,随着V2O5质量分数从0.5%增至9%,硫容从3%增加到12%,脱硝率在V2O5质量分数为0.5%到3%时脱硝率稳定在60%左右,继续增加V2O5质量分数,脱硝率降低。程序升温脱附 (TPD) 和红外光谱 (FTIR) 表征结果显示在脱硫脱硝过程中,催化剂表面有H2SO4, 铵盐和VOSO4生成, VOSO4的质量分数随催化剂中V2O5质量分数的提高而升高。使用后的催化剂可通过5%NH3在300 ℃再生,再生后催化剂的脱硝活性明显增加,NO转化率从新鲜样的67%提高到接近100%,对SO2的吸附也比新鲜样有所增加。     

具有中孔结构的SO2-4/Zr-HMS型固体超强酸的合成和结构表征

用TEOS-Zr-HAD-H2O-Ethanol体系合成了Zr-HMS的中孔分子筛, 脱除模板剂后用0.5 mol/L硫酸处理和550 ℃高温焙烧3 h, 制得一种中孔SO2-4/Zr-HMS超强酸催化剂. 采用XRD对其结构进行表征. 用指示剂法、 TG和NH3-TPD对其酸性进行了表征. 结果表明, 经过一系列处理后制得的SO2-4/Zr-HMS催化剂具备HMS中孔分子筛的结构特征, 其酸强度可达H0=-13.75. 在锆及SO2-4含量远远低于SO2-4/ZrO2的条件下, SO2-4/Zr-HMS催化剂对于苯酐和正丁醇酯化反应的活性仍高于SO2-4/ZrO2催化剂.     

SO2-4/SnO2催化剂的制备及其对苯硝化反应的催化活性

采用(NH4)2SO4溶液浸渍法制备了一系列SO2-4/SnO2催化剂(Cat-n,n=5,10,15,20),其结构经IR表征.以Cat-10(焙烧温度500℃)催化苯液相硝化反应的研究结果表明,引入SO2-4后催化剂的活性显著增加,硝基苯产率63.8%.     

具有中孔结构的SO4^2—／Zr—HMS型固体超强酸的合成和结构表征

用TEOS－Zr-HAD-H2O-Etheanol体系合成了Zr-HAD的中孔分子筛，脱除模板剂后用0．5mol/L硫酸处理和550℃高温焙烧3h，制得一种中孔SO4^2－／Zr-HAD超强酸催化剂，采用XRD对其结构进行表征，用指示剂法，TG和NH3－TPD对其酸性进行了表征。结果表明，经过一系列处理后制得的SO4^2-／Zr-HAD催化剂具备HMS中孔分子筛的结构特征，其酸强度可达H0＝－13．75，在锆及SO4^2-含量远远低于SO4^2-／ZrO2的条件下，SO4^2-／Zr-HAD催化剂对于苯酐和正丁醇酯化反应的活性仍高于SO4^2-／ZrO2催化剂。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.