Na4SeO5, ein neues Pentaoxoselenat(VI) – Synthese,Charakterisierung und Vergleich mit isotypem Na4MoO5

Na₄SeO₅, a Novel Pentaoxoselenate(VI) – Synthesis, Charakterisation, and Comparison with Na₄MoO₅ Na₄SeO₅ was prepared by high pressure solid state reaction at 500 °C and at a hydrostatic pressure of 2.5 Gpa from a mixture of Na₂O and Na₂SeO₄ in silver crucibles and Na₄MoO₅ by solid state reaction at 450 °C from a mixture of Na₂O and MoO₃. The crystal structures of both new compounds were solved and refined using X‐ray powder methods (Profilematching Na₄SeO₅: P1, a = 988.3(1), b = 988.4(1), c = 558.6(1) pm, α = 96.25(1)°, β = 96.24(1)°, γ = 113.41(1)°, R_p = 0.0783, R_wp = 0.1037. Profilematching Na₄MoO₅: P1, a = 999.5(1), b = 1002.0(1), c = 565.1(1) pm, α = 96.54(1)°, β = 96.29(1)°, γ = 113.35(1)°, R_p = 0.0623, R_wp = 0.0867). Both compounds contain novel XO₅^4– anions of approximately tetragonal pyramidal shape. The crystal structures are consistent with spectroscopic data (IR, Raman).     

Über die Darstellung der Dimercapto(methyl)sulfonium-Salze[CH3S(SH)2]+AsF−6 und [CH3S(SH)2]+SbCl−6 und der Bis(chlorthio)Methylsulfonium-Salze [CH3S(SCI)2]+ AsF6−und [CH3S(SCL)2]+SbCl−6

On the Preparation of Dimercapto(methyl)Sulfonium Salts [CH₃S(SH)₂]⁺ AsF₆^? and [CH₃S(SH)₂]⁺SbCl₆^? and the Bis(chlorothio)methylsulfonium Salts [CH₃S(SCI)₂]⁺ AsF₆^? and [CH₃S(SCI)₂]⁺ SbCl₆^? The preparation of the dimercapto(methyl)sulfonium salts [CH₃S(SH)₂]⁺ AsF₆^? and [CH₃S(SH)₂]⁺SbCl₆^? from [CH₃SCl₂]⁺ salts and H₂S at 195 K is reported. The salts are stable below 210 K. They are characterized by additional Raman spektroscopic measurements of the isotopic labelled cations [CH₃S(SD)₂]⁺, [CH₃S(³⁴SH)₂]⁺ and [CH₃S(₃₄SD)₂]⁺. The dimercapto(methyl)sulfonium salts are transfered into bis(chlorthio)methylsulfonium salts by reaction with Cl₂ at 195 K.     

Fe对胜利褐煤焦结构和气化反应性能的影响

酸洗褐煤负载不同含量的Fe催化剂在固定床反应器上进行热解,然后采用FT-IR、Raman spectra、TPD和TG研究Fe催化剂对煤焦官能团、碳微晶结构、表面活性位和气化反应性的影响。FT-IR结果表明,催化热解作用下煤焦中-OH、-CH₃、-CH₂活性官能团数量增加。Raman光谱测试结果显示,随着Fe含量的增加,I_G/I_all由0.095减少到0.087,I_D3/I_all由0.090增加至0.097,表明在Fe催化作用下部分大芳香环结构转变为小芳香环结构。TPD实验结果表明,活性位数量随着煤焦中Fe含量升高而不断增加。在3%含Fe量时煤焦活性位数量随着吸附温度的升高而增加,800 ℃后煤焦表面活性位数量开始降低。750 ℃条件下CO₂吸附量随着吸附时间的延长而增加,45 min后煤焦达到饱和吸附状态。煤焦-水蒸气等温气化实验表明,煤焦气化反应性与活性位数量有密切的关系,Fe催化剂主要通过增加煤焦表面活性位数量提高煤焦气化反应性。     

制备方法对MoO_3／ZrO_2结构的影响及MoO_3／ZrO_2固体超强酸的结构特征 Ⅱ．活性组分存在形态的研究

ＬＲＳ，ＸＲＤ，ＸＰＳ结果表明，仲钼酸铵浸渍仅经干燥的Ｚｒ（ＯＨ）４再焙烧制得的固体超强酸（ＭｏＯ３／ＺｒＯ２（Ⅰ））与浸渍晶态ＺｒＯ２制得的部分氧化催化剂（ＭｏＯ３／ＺｒＯ２（Ⅱ）中，活性组分的存在形式明显不同．在ＭｏＯ３／ＺｒＯ２（Ⅱ）中，ＭｏＯ３以二维聚钼酸根形式单层分散在ＺｒＯ２上（其中单斜ＺｒＯ２为主），在～９５０ｃｍ－１处出现特征拉曼宽峰，超出单层分散容量的部分以晶态ＭｏＯ３形式存在．在ＭｏＯ３／ＺｒＯ２（Ⅰ）中，活性相以二维聚钼酸根和Ｍｏ—Ｏ—Ｚｒ表面物种两种表面态存在于介稳的四方ＺｒＯ２上，后者在ＬＲＳ谱中表现为～８１４ｃｍ－１的宽峰；ＭｏＯ３含量超过一定值时，多余的ＭｏＯ３在５５０℃即与四方ＺｒＯ２发生反应形成体相Ｚｒ（ＭｏＯ４）２．Ｍｏ—Ｏ—Ｚｒ表面物种中，Ｍｏ（Ⅵ）是四配位的，与四方ＺｒＯ２结合很强，它很可能与ＭｏＯ３／ＺｒＯ２具有超强酸性有密切关系．