环己烷液相无催化剂的氧化动力学研究

采用搅拌釜反应器,在确认已排除传质因素对反应速率影响的情况下,研究了环己烷液相无催化剂的氧化反应动力学。应用自由基理论及最优化计算技术,从导出的8个候选动力学模型中,确定了最佳的动力学模型,它能满意地描述环已烷氧化过程。该动力学可为环己烷氧化工业生产操作条件的优化、反应器的选型及工业设计提供依据。     

FeAPO4-5杂原子分子筛的制备及催化氧化制取环己酮的研究

采用水热合成法合成出了一种杂原子FeAPO4-5分子筛。通过XRD、IR方法进行表征,分析其晶型结构,证实铁在AlPO-5分子筛上形成了稳定的活性中心。对催化剂反应条件进行系统地考察,结果表明实验所合成的杂原子FeAPO4-5分子筛有可能成为环己烷催化氧化制备环己酮的理想催化剂。     

Vapor Phase Selective Catalytic Oxidation of Cyclohexane over 13X Supported Metal Oxides in the Presence of Ozone

This article reports the application of ozone for the selective oxidation of cyclohexane over 13X molecular sieve supported various metal oxides at ambient temperatures. From the SEM, XRD and HR-TEM results, the impregnated metal oxides are highly dispersed on the support. The activity results reveal that Co/MS, Mo/MS, Cu/MS, and Ag/MS catalysts produce cyclohexanone/cyclohexanol as selective oxidation products, whereas Ce/MS, Mn/MS, and V/MS catalysts yield, predominantly, CO and CO₂. Among them, Co/MS catalyst exhibits better conversion of 12.2% with selectively of 58% to cyclohexanone/cyclohexanol, which is attributed to the simultaneous activation of ozone and cyclohexane (-C-H bond) at ambient conditions.     

白炭黑的液相分散工艺对溶聚丁苯橡胶改性研究

选用数显型高速分散机进行白炭黑环己烷浆液的制备,通过圆盘式离心沉降粒度仪测定了白炭黑在环己烷浆液中的粒径,采用自然沉降法评价了各批次浆液的稳定性。考察了偶联剂种类、用量、搅拌方式、反应温度等条件对浆液分散效果的影响。实验结果表明:硅烷偶联剂KH550的用量为白炭黑质量的10%,在15 000和20 000 r/min搅拌转速下分别分散5 min,温度为10℃时,白炭黑在环己烷中的分散效果最佳。将改性后的白炭黑液相混炼填充至丁苯橡胶中其力学性能相对于干法填充有一定提升。     

环己烷氯代合成氯代环己烷的研究

由环己烷出发，经光引发氯化制氯代环己烷。对该方法的各工艺条件（反应器、反应温度和光源等）对反应的选择性及转化率的影响进行了考察，确定了生产氯代环己烷的工艺条件。     

NHPI/SMA-Co多活性位点催化氧气氧化环己烷的工艺研究

研究了NHPI/SMA-Co多活性位点催化氧气氧化环己烷的反应。得出该反应的最佳反应条件为：5mL环己烷,10mL乙腈,NHPI/SMA-Co摩尔配比为10:3,0.04g NHPI/SMA-Co复合催化剂用量,反应温度120℃,初始氧压1.0MPa。在此条件下反应6h,环己烷转化率为19.84%,环己醇选择性22.23%,环己酮选择性38.65%,KA油选择性达60.88%。经过对催化剂进行多次重复使用实验,表明催化剂的活性在反应过程中无明显降低,可以循环使用。     

环己烷氧化制备环己酮工艺技术及研究进展

介绍了目前环己烷氧化制备环己酮的主要生产工艺和工艺改进情况;同时对最新环己酮合成方法进行了介绍,并对环己酮制备工艺的发展进行了展望。     

Reactive mass transfer at gas-liquid interfaces: impact of micro-scale fluid dynamics on yield and selectivity of liquid-phase cyclohexane oxidation

The impact of single-bubble wake dynamics on the reaction-enhanced mass transfer and on the yield and selectivity of the cyclohexane oxidation reaction was studied using a two-dimensional CFD-reaction model that was developed by our group. Temperature and the concentrations of the (desired) intermediate and (undesired) final products of this autocatalytic reaction were the parameters of this study. Two bubble types were studied: (a) a circular bubble with closed wake, and (b) an elliptical bubble with an unsteady, vortex-shedding wake. The main results of our work are: (1) Film theory over-predicts reaction-enhanced mass transfer since the assumption of an average film thickness is not justified. In order to study fast reaction systems on a reactor scale using coarse-grid CFD codes, a full bubble model, or correlations based on it, should be incorporated as a sub-grid micro model. (2) The bubble wake does not contribute to mass transfer in systems where reaction rates are low. For fast reactions, the local mass transfer rate in the wake can increase by several thousand percent. (3) Vortex shedding causes qualitatively different mixing since patches rich in the dissolved gas are quickly convected away from the bubble. Bubbles that cause vortex shedding will lead to a significantly higher conversion per volume than spherical bubbles. (4) Parallel-consecutive reactions with a high liquid-phase reactant concentration and with reaction rates that depend in an identical way on the dissolved gas concentration, are not micro-mixing sensitive in terms of selectivity. Since bubble shapes and sizes can be controlled by changing operating and design parameters, the yield of this reaction can be controlled.     

环己烷氧化液的废碱分离实验研究

针对环己烷氧化法制备环己酮中氧化液废碱的分离问题,在80kt/a环己酮试验装置上开发了环己烷氧化液的废碱分离技术,即将重力沉降、旋流分离和聚结分离3种分离技术依次串联组合的梯度分离技术,同时采用较为先进的两段逆流碱洗工艺,实现水的循环利用。对Na+的脱除效率可以达到50%,延长烷-塔开车周期6个月以上。     

Effect of superfine particles of alumina incorporated in the cavities of mordenite in enhancing selectivity

Alumina has been incorporated in the cavities of mordenite by the hydrolysis of Al³⁺ ions in the cavities with moist ammonia gas, following calcination at 450°C. The incorporation of the superfine particles of alumina into the cavities of the mordenite is assessed on the basis of the data of MAS ²⁷Al NMR measurements, X-ray powder diffraction and the amount of saturated adsorption of nitrogen for FAL/MZ. The acid properties, assessed using NH₃ TPD and FTIR studies, show the presence of Brønsted and Lewis acid sites on the catalyst, and an increase in acidic sites on incorporating alumina. The dehydrogenation selectivities of FAL/MZ, Al³⁺/MZ, H⁺/MZ, and Na⁺/MZ have been investigated. Brønsted acid sites largely enhance the ring-cleavage, whereas this incorporation of superfine particles of alumina significantly suppresses the ring-cleavage. Therefore, the incorporation of the superfine particles increases remarkably in the cyclohexene selectivity.