综合资讯

我国原甲酸三乙酯出口潜力巨大，对氨基酚市场前景广阔，我对部分进口乙醇胺征收反倾销税，2005年我国苯乙酸总需求将达1．8万t     

原甲酸三乙酯新合成工艺

原甲酸三乙酯新合成工艺崔学元，陈学敏（锦西化工总厂研究所）原甲酸三乙酯（又称三乙氧基甲烷）作为中间体广泛地用于医药工业，还用于合成丙烯酸系纤维及甲川类染料和花青染料，照相药品及感光材料。目前，国内外生产工艺均采用烧碱法合成原甲酸三乙酯，该工艺主要缺点...     

含原甲酸三乙酯体系等压汽液平衡的测定与关联

利用改进后Ｒｏｓｅ－Ｗｉｌｌｉａｍｓ釜测定了０．１０１３ＭＰａ下乙醇－原甲酸三乙酯，苯－原甲酸三乙酯体系的汽液平衡数据。实验数据通过了热力学一致性检验，采用威尔逊方程关联，获得较满意的结果，并对乙醇－苯－原甲酸三乙酯三元体系的汽液平衡进行了预测，计算精度可满足工程要求。     

取代的环丙烷乙酸乙酯的合成

环丙烷乙酸乙酯是通过环丙基烷基酮和醋酸铜（IV）在原甲酸三乙酯中，在70％高氯酸存在下，反应制得。在所有这类反应中，原甲酸三乙酯用作溶剂。     

原甲酸三乙酯的测定

原甲酸三乙酯在酸性条件下完全水解后再在碱性条件下水解，用酸标准溶液滴定过量的碱，从而得到原甲酸三乙酯的含量，该方法回收率在99.5-100.5%之间，标准偏差为0.15%。     

原甲酸三乙酯出口有潜力

2003年全球原甲酸三乙酯的总产量为2．1万吨，总消费量1．8万吨。国外有20余家公司生产原甲酸三乙酯，分布在美国、法国、德国、英国、印度和日本。德国德固萨公司产能最大，为3000吨／年。     

原甲酸三乙酯的合成与应用

概述了原甲酸三乙酯几种主要工业合成方法的工艺条件及存在的主要问题,并对原甲酸三乙酯在染料、医药、农药、感光材料等方面的应用进行了详细的介绍。最后对原甲酸三乙酯在国内的生产现状进行了分析,并对国内原甲酸三乙酯今后的发展提出几点建议。     

原甲酸三乙酯的生产方法

原甲酸三乙酯的生产方法朱秉谦李丽（锦西化工总厂有机分厂葫芦岛市１２５００１）（锦西化工总厂职工医院葫芦岛市１２５００１）１前言随着氟哌酸、环丙杀星等喹诺酮类抗菌药物在国内迅速广泛的应用，使生产这类药物的中间体———原甲酸三乙酯的需求量激增，生产厂家也...     

丙酮缩二乙醇的合成工艺改进

以原甲酸三乙酯为解水试剂，以氯化铵为催化剂，由无水乙醇和丙酮缩合制得丙酮缩二乙醇。通过单因素条件实验方法考察该反应，得到了适宜的工艺条件：丙酮26g（0.45mol），原甲酸三乙酯74g（0.5mol），乙醇75mL，氯化铵0.72g（0.0135mol），回流下反应3h，收率为77.5％。     

合成原甲酸三乙酯新工艺

研究了合成原甲酸三乙酯的一步法新工艺，收率达７０％，产品纯度大于９８％。     

Leveling of Vitreous Surfaces

A model was developed relating the variables involved in the leveling of an irregularity on a vitreous surface (such as a dry-process porcelain enamel) during heating. The variables are: (1) surface tension, (2) viscosity, (3) geometry of the irregularity, (4) coating thickness, and (5) firing time. The equation derived was:

where h ₀= height of irregularity at t = 0, h = height of irregularity at t = t, t = time, y = surface tension, X = average coating thickness, ν= viscosity, and a = half width of the irregularity at the mean thickness. The derived relation was verified using a coating of a simple glass having known surface tension and viscosity.     

Pressure-Temperature Phase Diagram of Zirconia

The pressure-temperature phase diagram of zirconia was determined by optical microscopy and X-ray diffraction techniques using a diamond anvil pressure cell. At room temperature, monoclinic ZrO₂ transforms to a tetragonal phase ( t II) which is related to the high-temperature tetragonal structure ( t I). The transformation pressure exhibits hysteresis and is cycle dependent. At room temperature, the initial transformation pressure for the monoclinic- t II transition on a virgin monoclinic crystal can be as high as 4.4 GPa; on subsequent cycling the transition pressure ultimately lowers to 3.29 ± 0.06 GPa. The pressure for the reverse transition is essentially constant at 2.75 ± 0.06 GPa. At pressures > 16.6 GPa, the t II form transforms to the orthorhombic cotunnite (PbCl₂) structure. With increasing temperature, the t II form transforms to the high-temperature tetragonal phase. For increasing P and T , the monoclinic- t I- t II triple point is located at T = 596°± 18°C and P = 2.26 ± 0.28 GPa, whereas for decreasing P and T , the triple point is found at T = 535°± 25°C and P = 1.7 ± 0.28 GPa.     

间歇过滤操作时间优化

利用活性碳 ,通过间歇过滤操作 ,除去植酸浆液的色素杂质 ,对过滤时间进行优化 ,使产量最大的优化时间t应满足dvdt=vt0 +t;使成本最低的优化时间t应满足dvdt=vt+(a0 t0 +a1) /a 。通过实验验证 ,该方法是切实可行的。该法也适用于其它间歇操作时间优化。     

A RANDOM PARAMETER PROCESS FOR MODELING AND FORECASTING TIME SERIES

Abstract. A generalized autoregressive (GAR) process {Z ( t ) ; t = 0 , ±1, …} is defined to satisfy the recurrence relation Z(t) = A_θ (t)Z (t -l)+ u( t ), where {A_θ(t); t = 0,±1, …} is itself a stochastic process depending on a vector parameter θ and where {u( t ); t = 0, ±1, …} is white noise with Eu ² ( t ) = a ². This paper develops theory and methodology and implementing the class of GAR processes for time series modeling and forecasting. Conditions on the 'parameter process' { A _θ ( t ); t = 0, ±1, …} are obtained for the existence of a GAR process; necessary and sufficient conditions on { A_θ ( t ) ; t = 0, ±1, …} for existence of a stationary GAR process are also obtained. Procedures are developed for computing maximum likelihood estimates of the parameters 0 and u² and for computing the minimum mean squared error forecasts for GAR processes.     

超(近)临界流体中甲苯氧化成苯甲醛

分别研究了在超临界二氧化碳和近临界水中以过氧化氢为氧源、无催化剂条件下,甲苯氧化成苯甲醛的工艺优化及氧化反应动力学.研究结果表明,在超临界二氧化碳中的最佳工艺条件为：P=25 MPa,T=180 ℃,t=4 h,η=2.5.氧化反应呈现零级反应特征,反应活化能E_a=50.9 kJ•mol^-1.在近临界水中的最佳工艺条件为：P>P₀,T=350 ℃,t=1 h,η=3.5.氧化反应由两个一级反应组成连串反应,反应活化能分别为E_a1=89 kJ•mol^-1,E_a2=76 kJ•mol^-1.     

Über die Abhängigkeit der Dichte,der Oberflächenspannung und der Viskosität von der Kettenlänge bei Äther-Estern des Äthylenglykols im Vergleich zu anderen homologen Reihen

The Relationship of Density, Surface Tension and Viscosity to the Chain-Length of Ether-Esters of Ethyleneglycol in Comparison to Other Homologous Series A number of glycolether-esters of the type R₁? O? CH₂CH₂? OCOR₂ were synthesized. For these compounds as well as for a few other non-branched homologous series, the following relationship showing the dependence of density, surface tension and viscosity from the chain-length was observed: X_t = X_{t, Z = ∞} + k_t/Z, whereby X_t represents the physical property concerned at the temperature t, X_{t, Z = ∞} the limiting value of the aforesaid property at infinite chain-length and k_t a characteristic constant of the homologous series involved at the temperature t. The above relationship was found to be generally applicable with sufficient accuracy.     

CO高温变换催化剂浸渍条件研究

采用γ-Al₂O₃作载体,Ni^2＋、Cu^2＋和Mn^2＋水溶液为浸渍液,进行制备无铬CO高温变换催化剂浸渍条件的研究。由实验数据回归出Ni^2＋、Cu^2＋和Mn^2＋活性组分在载体上的浸渍动力学方程,得到Ni^2＋、Cu^2＋和Mn^2＋组分在载体上浸渍的速率常数为：k_Ni2＋= 0.000 2,k_Cu2＋=0.000 2,k_Mn2＋=0.001 6。Freundlich等温吸附表达式为：lnC_Ni2＋=－0.000 2 t＋4.447 4,lnC_Cu2＋=－0.000 2 t＋4.590 9和lnC_Mn2＋=－0.001 6 t＋3.589 5。考察了催化剂中活性组分含量与共浸渍组分浓度的关系,并得出从浸前液浓度来预测和控制催化剂成品中Ni^2＋、Cu^2＋和Mn^2＋活性组分含量的经验式。     

顺式氰戊菊酯在大棚、露地条件下甘蓝和土壤中残留动态的对比研究

采用田间试验方法,对5%顺式氰戊菊酯微乳剂在大棚、露地条件下甘蓝及土壤中残留动态进行了对比研究。结果表明,顺式氰戊菊酯在大棚甘蓝中降解动态方程为Ct=0.1005e^-0.1023t,露地为Ct=0.1417e^-0.1764t,半衰期分别为6.8d和4.2d。顺式氰戊菊酯在大棚土壤中降解动态方程为Ct=0.07326e^-0.0703t,露地为Ct=0.0959e^-0.073t,半衰期分别为9.8d和5.7d。顺式氰戊菊酯在大棚上的降解速度要稍慢于露地。     

Polyvariograms and their Asymptotes

A definition of a polyvariogram (PV) γ _b ( h )( h = 1, 2, ...) of order b ( b ≥ max(0, d − 1) is suggested for time series { Z ( t })} satisfying {∇ ^d ( Z ( t ) = W ( t ) (where d is a non-negative integer and { W ( t )} is a second-order stationary time series and is not over-differenced). When b = 0, 1 and 2, this definition corresponds to Cressie's ( J. Am. Stat. Assoc. 83 (1988), 1108–16; 85 (1990), 272) semivariogram linvariogram and quadvariogram respectively and is simpler. Under very general conditions about { W ( t )}, we obtain the relationship between γ _b ( h ) and the autocovariance function of { W ( t )} and show that the asymptote of γ _b ( h ) is a straight line having a positive slope when b = d − 1 and levelling out when b ≥ d .
A definition of a sample polyvariogram (SPV) of order b is given and is shown to be an unbiased and consistent estimate of the PV; and further, some uniformly (in h ) almost sure convergence rates are obtained. These properties provide theoretical support for using the SPV to replace the practically unknown PV and generalize the guidelines for identifying d given by Cressie, where { W ( t )} was restricted to a white noise and b ≤ 2. Some further asymptotic theorems and avenues for using them for statistically testing d and parameters of models for { W ( t )} are briefly introduced.     

Synthesis and Characterization of Zinc Sulfide/Gallium Phosphide Nanocomposite Powders

Nanocomposite powders between zinc sulfide and gallium phosphide were synthesized. Monodisperse, submicrometer, spherical, and porous clusters of ZnS nanocrystallites were used as a host material, into which a solution containing a phosphinogallane, [( t -Bu)₂GaPR₂] _x wherein R = i -Pr, x = 2 or R = t -Bu, x = 1, was impregnated. The pure ZnS powders and the composite powders obtained after flash pyrolysis at 600°C were subsequently heat-treated at various temperatures ranging from 500° to 900°C and characterized using a variety of techniques. While pure ZnS powders undergo significant grain growth and morphology change at temperatures as low as 600°C, the composite Powders maintain their integrity up to 800°C.