Simulation experiments on the reaction system of CH4-MgSO4-H2O

H2S-rich gas in carbonate reservoirs is usually attributed to thermochemical sulfate reduction （TSR）. In this paper, thermal simulation experiments on the reaction system of CH4-MgSO4-H2O were carried out using autoclave at 425℃--525℃. The threshold temperature for initiating TSR is much lower than our previous studies （550℃）. Properties of the reaction products were analyzed by microcoulometry, gas-chromatography （GC）, Fourier transform-infrared spectrometry （FT-IR） and X-ray diffraction （XRD） methods. Thermodynamics and reaction kinetics of TSR processes were investigated on the basis of the experimental data. The results show that thermochemical reduction of magnesium sulfate with methane can proceed spontaneously to produce magnesium oxide, hydrogen sulfur, and carbon dioxide as the main products, and high temperature is thermodynamically favorable to the reaction. Ac- cording to the reaction model, the calculated activation energy of TSR is 101.894 kJ/mol, which is lower than that by most previous studies. Mg^2＋ may have played a role of catalytic action in the process of TSR. The elementary steps of TSR and reaction mechanism were discussed tentatively. The study can provide important information on the explanation of geochemical depth limit for natural gas and on the generation of high H2S gas in deep carbonates reservoirs.     

CH3O2+NO自由基反应体系的机理研究

NO可以经过一系列反应通道从CH3O2自由基夺取氧,生成NO2和CH3O．在B3LYP／6-311 G 高基组水平上,使用Gamaioan98程序包对此反应体系的各物种进行了全优化,找到了4个单线态和2个三线态中间体、2个单线态和1个三线态过渡态,证明了2条单线态和1条3线态反应通道的存在,并阐明了反应机理,动力学研究表明,CH3O2 NO→TS3→IM4→CH3O NO2是最可行的反应通道．     

CH2(X3B1)+O2→CH2O+O(3P)自由基反应机理理论研究

采用相关能校正自洽场分子轨道MP2/6-311G**从头计算法,结合能量梯度法研究了CH2(X3B1)+O2→CH2O+O的反应机理,优化了反应势能面上反应物、过渡态、中间体和产物的几何构型,并采用内禀反应坐标理论(IRC)计算了该反应的反应途径,得出该反应为一历经中间体的分步反应,支持了实验工作者提出的机理.     

浅谈乙烯与溴的四氯化碳溶液及溴水的反应

乙烯可使溴的四氯化碳溶液和溴水褪色,但生成的产物不同,两种试剂不等效.     

K2CO3-KCl-K2B4O7-H2O四元体系298 K介稳相平衡的实验研究

采用等温蒸发法研究了K2CO3-KCl-K2B4O7-H2O四元体系298 K介稳平衡相关系,并测定了该体系达介稳平衡时液相的密度、折光率和pH值等物化性质.根据实验数据,绘制了该体系298 K的介稳相图及物化性质-组成图.结果表明:该四元体系属简单共饱型,无复盐或固溶体形成;其溶解度等温图含有一个共饱点、三条单变量曲线和3个结晶相区.3个结晶相区分别对应于K2B4O7·4H2O,K2CO3·3/2 H2O和KCl.共饱点的平衡液相组成为w(K2CO3)=51.57%,w(KCl)=1.09%,w(K2B4O7)=1.29%,所对应的平衡固相为K2CO3·3/2 H2O KCl K2B4O7·4H2O.     

The genesis of H2S in the Weiyuan Gas Field, Sichuan Basin and its evidence

The Sinian Dengying Formation gas pool in Weiyuan is the oldest large-scale sulfur-bearing gas field in China, which has a H2S content ranging from 0.8% to 1.4%. The Cambrian Xixiangchi Formation gas pool discovered recently above the Dengying Formation contains gas geochemical behaviors similar to those of Dengying Formation but different in sulfur isotopes of H2S. Investigations show that though these two Sinian and Cambrian gas pools are separate ones, they share the same Cambrian source rock. The higher dry coefficient, heavier carbon isotopes, sulfur isotopes of sulfide, lower filling of gas pools, formation water characteristics, reservoir properties and H2S distribution, indicate that H2S in both the Sinian and Cambrian gas pools originates from TSR. The sulfur isotopes of sulfates have shown that H2S was formed in respective pools, namely hydrocarbons charged into the pools reacted with the Dengying Formation and the Xixiangchi Formation gypsum （TSR）, respectively, to form H2S. Compared with sulfur isotopes of sulfates in each pool, δ^34S values of H2S are 8‰ lighter for the Dengying Formation pool and 12‰ lighter for the Xixiangchi Formation pool, respectively, which is attributed to the difference in temperatures of TSR occurrence. The reservoir temperature of the Xixiangchi Formation pool is about 40℃ lower than that of the Dengying Formation pool. Temperature plays a controlling role in both the sulfur isotopic fractionation and amounts of H2S generation during TSR.     

CaO-SiO2-P2O5-H2O系统中CBC材料的原料配比研究

以硅溶胶、磷酸和硝酸钙为原料,以１８种不同化学成分的原料配比分别合成了ＣａＯ－ＳｉＯ２－Ｐ２Ｏ５－Ｈ２Ｏ系统中的ＣＢＣ材料。引入磷率（ＰＭ）或硅率（ＳＭ）及氧化钙标准值（ＣＳｔ）的概念,综合材料的化学成分及矿物组成的分析,以测得的劈裂抗拉强度指标为依据,对材料的配料问题进行研究。结果表明,欲制得高劈裂抗拉强度的材料,应控制ＰＭ为２．０－３．０,ＣＳｔ为９０￣１０５,或化学组成范围为：ＣａＯ,５３．     

热力学模型对KCI-K2SO4-H2O体系溶解度的预测

用Pitzer-Simonson-aegg热力学模型(PSC模型)和Pitzer模型,结合KCl-H2O,K2SO4-H2O以及KCl-K2SO4-H2O体系水活度和溶解度实验数据,分别计算KC1-H2O体系和K2SO4-H2O体系的溶解度相图,及KCl-K2 SO4-H2O体系在273.15 K,298.15 K,3...     

O（^3P）＋CH3CF=CH2气相反应动力学的理论研究

采用二级微扰理论,在MP2（full）／6—311＋＋G（d,p）理论水平上对O（^3P）与CH3CF=CH2气相反应在三重态势能面上可能的反应机理进行了理论研究,全参数优化了反应过程中反应物、中间体、过渡态和产物等各物种的几何构型,并进行了频率计算．在G3MP2水平上计算了各驻点的能量．计算结果表明,在298．15K下,经过IM2生成CH3＋CH2COF产物通道的能垒较低,为主反应通道,而从IM1出发生成H＋CH3CFCHO和从IM2出发生成CH2＋CH3COF是次要的产物通道．利用经Wigner校正的Eyring过渡态理论计算了在298．15～1500K温度范围内,1个大气压下该反应的速率常数．结果表明,整个反应的速率常数受温度的影响较为复杂．     

复盐K3Fe(C2O4)3·3H2O的热分析研究

合成复盐K3Fe(C2O4)33H2O,利用TG-DTG技术分析它们在氮气气氛中的热分解过程,并用微分法中的Achar法和积分法中的Coats-Redfern法对热分解的非等温动力学数据进行研究,推测出可能的热分解反应机理,求出反应的表观活化能。     

氟代次甲基与氧气的反应机理研究

在B3LYP/6-311G(d,p)水平上研究了CF自由基与O2反应的微观机理.对反应势能面上的各反应物、过渡态、中间体和产物的几何结构进行了全参数优化,且在QCISD/6-311G(d,p)水平上计算了它们的能量.研究发现CF+O2反应在高温过程中重要,有3个产物通道,即F+CO2、FCO+O和FO+CO,其中最有竞争力的通道为F+CO2,其次为FCO+O通道,FO+CO通道可能难发生.与CH+O2反应比较发现两者有相似的地方,如第一步都是CX(X=H或F)自由基进攻O2分子中的一个氧原子形成链状过氧化物XCOO.两反应机理也存在很多不同之处,如HCO+O和FCO+O通道的形成过程有很大的不同;两反应速率也相差较大.CH+O2反应快,CF+O2反应慢.     

低热固相法合成纳米(NH4)3PMo12O40·4H2O及其机理的研究

通过低热固相反应合成了纳米(NH4)3PMo12O40*4H2O,XRD、31P NMR研究发现,在此固相反应的4个步骤中(扩散,反应,成核,生长),反应的速率控制步骤是产物的成核.     

ZnCo2O4尖晶石纳米粉体的新型共沉淀法合成及表征

以草酸为沉淀剂、乙醇为溶剂,通过新型共沉淀法合成分子前躯体锌钴草酸复合盐ZnCo2(C2O4)3.4H2O,对该前躯体在不同温度下热处理即可制得锌钴尖晶石粉体.利用热重分析仪(TGA)和差示扫描量热仪(DSC)对前躯体热分解过程分别进行热失重分析和动力学分析.结果表明,前躯体热分解仅经历2个热失重过程(脱结晶水和最后分解)且最后分解过程遵循随机成核和核随后生长单一的动力学机理,活化能不随转化率的变化而变化.由此说明前驱体为草酸复合盐而不是二元混合盐.利用X-射线衍射(XRD)、红外光谱(IR)和透射电子显微镜(TEM)等分析手段对尖晶石粉体进行表征.结果显示,前躯体在低温段450~650℃煅烧2 h即可获得单相、颗粒细小均匀的尖晶石粉体,高温750℃煅烧,得到ZnO和缺锌的锌钴尖晶石的混合物.     

[Bmim]BF_4-H_2O体系超额摩尔体积测定及关联

合成并表征离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim]BF4),测定[Bmim]BF4-H2O二元混合物在不同温度下的密度值和超额摩尔体积.结果表明,在所有组成范围内,体系的超额摩尔体积都为正值,且不同温度下的等温线都存在一极大值点;同时,所有等温线的极值点所对应的H2O的摩尔分数基本上在50%左右.不同温度下超额摩尔集体的变化趋势相似,而在组成相同的情况下,随着温度的增加,超额摩尔体积变大.采用Redlich-Kister方程对[Bmim]BF4-H2O的超额摩尔体积进行关联,最大标准偏差为1.32%.     

CH_4和CO_2制合成气的负载型锦催化剂的制备研究

ＣＨ_４和ＣＯ_２制合成气的负载型锦催化剂的制备研究邓存，路勇，丁雪加，沈师孔（宁德师范高等专科学校化学系）（中国科学院兰州化学物理研究所）负载型镍催化剂的制备及反应条件对其ＣＨ４与ＣＯ２催化反应性能影响的研究，对于这类制合成气过程的实际应用开发将具有...     

五元体系Li~+,K~+//Cl~-,B_4O_7~(2-),CO_3~(2-)-H_2O在298K时相平衡的实验研究

采用等温溶解平衡法研究了五元体系 L i+ ,K+ / / Cl- ,B4O2 -7,CO2 -3- H2 O在 2 98K时相关系和平衡液相物化性质。对各组分的溶解度以及密度、折光率、粘度、电导率和 p H值进行了测定 ,并绘制了相关相图 ,得到 5个结晶相区和 3个共饱点。该体系没有固溶体和复盐生成 ,为简单共饱和型体系。     

K~+、NH_4~+//C l~-、SO_4~(2-)、CH_3OH-H_2O体系相图

氯化钾与硫酸铵复分解制备硫酸钾工艺具有诸多优点,但其转化率较低;在反应系统中添加有机溶剂可降低硫酸钾的溶解度,从而有效地提高转化率;以一定摩尔质量的甲醇溶液为溶剂,研究确定了25℃时K+、NH4+//C l-、SO42-、CH3OH-H2O体系相图;结果表明,该体系没有复盐生成,为简单共饱和型,反应转化率显著提高。     

纳米四水羟基硝酸氧铋的制备及在氮气气氛下的热分解动力学

利用反相微乳液法制备出了纳米四水羟基硝酸氧铋[Bi6O4(OH)4](NO3)6(H2O)4,并以热分析为手段对纳米[Bi6O4(OH)4](NO3)6(H 2O)4的热分解过程和非等温热分解动力学机理进行了研究.动力学研究确定了[Bi6O4(OH)4](NO3)6(H2O)4脱硝酸根反应属于球对称的三维扩散的D3机理,热分解表观活化能为E=98.90033 kJ/mol,lnA=27.13109.     

Novel photocatalysis oxidation system UV/Fe^2＋/air to degrade 4-CP wastewater

This paper reported the degradation of 4-CP wastewater by a novel photocatalysis oxidation system-- UV/Fe^2＋/air system, in which air was used as a cheap oxidant that reacted with the excitation state of organics to form H2O2 under the UV light. The formed H2O2 reacted with the added ferrous ion to form Fenton reaction and led to the quick degradation of organic pollutants. It was found that 4-CP could be completely removed within 40 min. The degradation of 4-CP in the UV/Fe^2＋/air system was superior to the conventional UV/Fenton system （the initial concentration of H2O2 was 22 mg·L^-1）. UV/Fe^2＋/air is an effective and cheap method for treatment of the organics that can be excited by UV light.