粗异戊烯的醚化

研究了苯磺酸型树脂催化的异戊烯和甲醇的醚化,考查了温度、醇烯比和空速对反应的影响。结果表明在反应温度为59～67℃、甲醇与异戊烯的摩尔比值为1 4～1 6、液时空速为1 1～1 5h-1时反应的转化率大于70%。     

Xylene Isomerization in the Liquid Phase Using Large‐Pore Zeolites

Three large‐pore zeolites, Beta with Si/Al ratios of 25 and 35 and Mordenite with an Si/Al ratio of 30, were studied in the conversion of o‐xylene at 493 K. Maximum conversion was achieved by the catalyst with the highest Si/Al ratio due to faster diffusion of the isomer inside the zeolite channels because of the lower acidity of the solid even with larger crystal size. A kinetic study was then carried out over this catalyst between 473 and 513 K in a batch reactor in the liquid phase. The activation energies obtained do not indicate the presence of diffusional constraints towards any isomer. Finally, the kinetic model obtained was simulated in a fixed‐bed reactor and compared to ZSM‐5 in the temperature range from 493 to 533 K. An increment in p‐xylene production of 20 % on average was obtained.     

Industrial Xylene/Ethylbenzene Isomerization Unit Using a Radial‐Flow Reactor and EUO‐Type Zeolite

A mathematical model based on 34 days continuous operation of an industrial isomerization unit was developed. The unit involves a radial‐flow reactor with a catalyst capable of converting xylenes and ethylbenzene to mixed xylenes. The catalyst contains EU‐1 zeolite, platinum, and alumina as binder. Two reactions are considered, i.e., ethylbenzene isomerization and xylene isomerization. The rates are based on the Hougen‐Watson model according to the literature. An optimization procedure based on the trust‐region‐reflective algorithm was carried out in order to obtain new kinetic constants that minimize the difference between the actual and the calculated values. The standard error of the parameters estimated was calculated through the deleted‐one Jackknife method.     

轻质烷烃异构化催化剂及机理研究进展

简介了近年来国内外轻质烷烃异构化新工艺和新催化剂,综述了近年来的经典及新提出的异构化反应机理.根据反应机理针对不同催化剂体系总结了提高异构催化剂反应活性和选择性的途径,并展望了反应机理在制备新型催化剂领域以及提高催化剂的活性和选择性方面的重要指导意义.     

新型二甲苯异构化催化剂的工业生产及应用

针对二甲苯异构化催化剂的需求热点,开发了新型C8芳烃异构化催化剂。该催化剂在抚顺石化公司催化剂厂工业批量生产36 t,在辽阳分公司对二甲苯装置上进行工业应用,并针对该催化剂的反应特点,对装置进行改造,催化剂投料后,乙苯转化率达到22.88%,PX/ΣX达到23.32。从工业标定的结果和装置运行情况看,各项技术指标均达到或超过了项目合同指标要求。     

正丁烷异构化催化剂的制备及其反应的研究

制备了一系列担载贵金属Pt的分子筛催化剂，评价了不同载Pt量对催化剂活性的影响。分子筛Pt含量的变化对反应结果影响很大，确定了载Pt量为催化剂总量的0．2％Pt/HZSM-5催化剂，能使正丁烷转化率＞40％，异丁烷选择性＞80％，同时考虑了反应温度，反应压力和H2／nC4^0对正丁烷异构化反应转化率及选择性的影响，结果表明：反应温度350－450℃，反应压力1．0－2．0MPa;H2/nC40－1．3等工艺条件较适合于正丁烷异构化反应，担载贵金属Pt的分子筛型催化剂对正丁烷异构化反应是一种很理想的催化剂。     

Isomerization of n-hexane over Platinum loaded zeolite catalysts

The isomerization of n-hexane over Pt-loaded Hβ, H-ZSM-5 and H-dealuminated mordenite was studied at temperatures lower than 573 K under atmospheric pressure. It was found that Pt loaded H β showed the highest activity and selectivity of these three catalysts. Namely, the conversion of hexane was 76 C-% and selectivities to dimethylbutanes, methylpentanes and cracking products were 19.4, 76.2 and 4.4 C-%, respectively, under the following conditions: reaction temperature, 548 K; W/ F, 5 g h mol⁻¹; molar ratio of hydrogen to n-hexane, 4. Pt/Hβ catalyst showed a good stability, because Hβ has acid sites with medium strength and three-dimensional large pores. We can adjust the balance between metallic sites and acid sites to obtain right catalyst which has the highest activity and the highest selectivity for the isomerization of hexane.     

异佛尔酮催化异构化的精馏工艺研究

以α-异佛尔酮为原料,催化异构化制备β-异佛尔酮。研究了精馏柱类型、塔顶温度、催化剂、催化剂用量及回流比对产品纯度的影响。在1.5 m不锈钢θ环填充柱,回流比为20,塔顶温度为120℃条件下,β-异佛尔酮纯度为96.5%。     

Catalytic Upgrading of Phenolic Oil by Etherification with Methanol

Catalytic etherification of phenolic oil with methanol was investigated to decrease the polarity and acidity of the product oil. The catalyst KH₂PO₄/activated alumina (AA) provided the best performance due to its excellent dehydration and anti‐coking property. When catalyzed by KH₂PO₄‐AA, the content of aryl ethers increased with rising temperature during the early stage but decreased at 500 °C. Alkoxy phenols had an inhibiting effect on etherification of alkyl phenols due to adsorption competition. Aryl ethers were mostly generated from alkyl phenols, while alkoxy phenols also contributed by simultaneous conversion to dialkoxybenzenes and diphenols, with a higher selectivity to diphenols. This explained the reduced alkoxy phenols and more generated alkyl phenols and aryl ethers at 350 °C.     

异构化催化剂Pd／HM结焦失活的再生

运用ＴＥＭ、ＴＰＤ、ＸＲＤ等技术考察了烧焦温度对异构化催化剂Ｐｄ／ＨＭ再生性能的影响。结果表明：在８２３Ｋ时，催化剂上金属钯粒子能重新分散，催化剂恢复活性，且稳定性不变，二次再生性也较好。     

Improvement of Lubricant Materials Using Ruthenium Isomerization

Production of an effective industrial lubricant additive from vegetable oils is a high profile and difficult undertaking. One candidate is alkyl 9(10)-dibutylphosphonostearate, which has been made through a radical transformation of alkyl 9-cis-octadecanoate. It is effective, but still suffers from drawbacks. In this report, that synthesis is combined with a ruthenium based isomerization process to create not just one, but an entire series of new chemical compounds. A low level of [Ru(CO)₂(EtCO₂)]_n is first used for the isomerization of the starting material, then radical chemistry is employed. A series of methyl dibutylphosphonooctadecanoates was made. In an analogous fashion, trans-7-tetradecene was also isomerized and then polymerized. As in the phosphonate case, the follow-up chemistry could be performed in the presence of the residual isomerization catalyst. The alkane:alkene ratio, observed by ¹H NMR, was found to change from 14:1 in the isomerized starting material to a value of 41:1 in the polymerized material. This methodology, isomerization in tandem with other reactions, gives suitable routes to both biobased polyolefins, and biobased phosphonates, potential key ingredients in biobased lubrication formulations.     

Isomerization of Alpha-pinene Over Acid Treated Natural Zeolite

In this study, isomerization of α-pinene was studied over several acid-treated natural zeolite catalysts rich in clinoptilolite. Zeolite samples were contacted with HCl at different concentrations at 30°C or at 60°C for 3 and 24 hours and tested in isomerization reaction of alpha-pinene. The catalysts prepared were characterized by XRD, nitrogen adsorption, and acidity studies. Acidity strength and the distribution of Lewis and Brönsted acid sites of the catalysts were determined, and their catalytic activities in α-pinene isomerization and selectivities to main reaction products, camphene and limonene, were investigated. Acid treatment improved the selectivity of catalyst samples to camphene, decreasing the selectivity to limonene, probably forcing limonene to secondary reactions at high conversions.

The kinetics of α-pinene consumption was described by first-order kinetics. Two kinetic models were tested for the reaction mechanism and one model was found to give a good correlation between the theoretical and experimental data. In the models, the key intermediate was the pinylcarbonium ion, which was formed irreversibly from α-pinene.

Number and distribution of Lewis and Brönsted acid sites affect the formation of bicyclic and monocyclic products.     

Isomerization of alkyl naphthalene and refining of 2-methylnaphthalene

A preparation process of 2-methylnaphthalene (2-MN) was proposed by isomerization, side-stream distillation and extractive distillation. The isomerization of alkyl naphthalene was catalyzed by acid-treated HBEA zeolites, and the 2-MN selectivity of isomerization was 92.70%. Side-stream distillation and extractive distillation were investigated by simulation, and effects of operation parameters on 2-MN were studied. Further, the simulated results were verified by experiment. Under the optimal condition, the mass fraction of 2-MN reached to 98.09%in the product, and the yield was 83.84%in refining process.     

Solvent Free Microwave Assisted Isomerization of N‐Nitropyrazoles

This paper describes solvent‐free isomerization of N‐nitropyrazoles under microwave irradiation to achieve a new green chemistry procedure for the synthesis of C‐ nitropyrazoles in good to excellent yields. The presented procedure requires less time, offers simplified workup procedure, needs no obnoxious solvents, and may be used for the preparation of several C‐nitropyrazoles.     

Isomerization of n-pentane catalyzed by amide-AlCl3-based ionic liquid analogs with various additives

The isomerization of n-pentane to generate high-quality blending components for clean gasoline was catalyzed by several amide-AlCl_3-based ionic liquid(IL) analogs with various amides as donor molecules. The catalytic performance of these IL analogs was evaluated in a magnetic agitated autoclave operated in batch mode.IL analog based n-methylacetamide(NMA)-AlCl_3 with the amide/AlCl_3 molar ratio of 0.65 showed excellent performance toward n-pentane isomerization because 0.65 NMA-1.0 AlCl_3 had a low viscosity and bidentate coordination structure. The influences of reaction time, reaction temperature, and stirring speed on the catalytic performance were also investigated. Optimal reaction conditions comprised the reaction time of 1 h, the reaction temperature of 40 °C, and the stirring speed of 1500 r·min~(-1). Under optimal condition, the n-C5 conversion,research octane number(RON) increment, total liquids yield, and isoparaffin yield in isomerized oil were56.80%, 13.51, 89.90 wt%, and 44.32 wt%, respectively. A new mathematical model was constructed to predict the relationships among RON increment, RON increment/n-C5 conversion ratio, and n-C5 conversion. The new model indicated that an appropriate conversion per pass of n-C5 did not exceed 50%–55%. Various cycloparaffin additives were used to improve the catalytic performance of 0.65 NMA-1.0 AlCl_3. The n-C5 conversion increased from 56.80% to 67.32%. The RON increment, total liquids yield, and isoparaffin yield reached 17.83, 97.36 wt%,and 63.74 wt%, respectively.     

Isomerization of n-butane: Conversion as a function of sulfate loading on sulfated zirconia catalysts

Sulfur loading on a sulfated zirconia catalyst was studied as a function of H 2 SO 4 concentration. The resulting catalytic activity was tested using the isomerization of n -butane as a reaction probe at 200°C. Optimum catalytic activity was observed for a catalyst prepared using 0.5 N H 2 SO 4 . The amount of carbon required to completely deactivate the catalyst was determined using a TGA/FTIR technique. For all of the catalysts synthesized in this study it was found that two active sulfate sites were poisoned by a single deposited carbon atom. Using this information, an active site composed of two coupled sulfate sites, perhaps a surface pyrosulfate site, is suggested. Using a TGA/FTIR technique it was found that the number of catalytically active sulfate sites never exceeded 14% of the total sulfate loading. These results were also supported by calorimetric studies.     

催化剂酸性对正辛烷异构化反应行为研究

以正辛烷作为反应模型化合物,在连续微型反应器上考察了经稀土元素改性的LKZ-1分子筛的临氢异构化性能,并探讨了不同稀土含量对其表面酸性的影响,试验结果表明：稀土元素的引入使分子筛表面的B酸减少,L酸增加,异构化选择性提高,并且当稀土元素含量在2％时,中强酸分布最高,并且单甲基支链异构体含量也最高。     

Catalytic Performances of Hollow Li3PO4 Spheres for Propylene Oxide Isomerization

Three Li₃PO₄ catalysts with hollow structure were prepared: N-Li₃PO₄ (Na₃PO₄ added to Li₃PO₄), L-Li₃PO₄ (LiOH added to Na₃PO₄), and S-Li₃PO₄ (LiOH and Na₃PO₄ added simultaneously). As a catalyst for propylene oxide isomerization, L-Li₃PO₄ exhibits the highest conversion and selectivity among the three samples. And the change of Li during the isomerization reaction was discussed. There are two Li ions in the crystal lattice (Li_1s1 and Li_1s2) based on the X-ray photoelectron spectroscopy (XPS) spectra. After catalytic reaction, the ratio of the surface atomic Li_1s1/Li_1s2 concentration changes from 1:1 to 1.32:1, indicating the motion and shift of Li ions.     

Exploiting Adsorption/Diffusion Synergy in MFI-Catalyzed Hexane Isomerization Reactor

The isomerization of n-hexane to produce mono- and di-branched isomers is an important process for octane enhancement of gasoline. In a fixed bed reactor, packed with MFI catalyst, there is synergy between mixture adsorption equilibrium and intra-crystalline diffusion. This synergy is best exploited by operating the reactor in a transient manner, whereby the desired products consisting of the branched isomers can be recovered from the exiting gas mixture during the early stages of transience. This strategy essentially results in a combination of reaction and separation in a single fixed bed device.