MCM-49分子筛的合成及其对烷基化反应的催化性能

The MCM 49 zeolite was successfully synthesized using an organic mixture solution (OMS) yielded from hydrogenation of caprolactam as the template instead of the pure hexamethyleneimine (HMI). The OMS contains HMI (76 0%～84 0%), caprolactam (1 0%～10 0%), water, and a few by products. So the synthesis cost of the MCM 49 zeolite decreases obviously. The MCM 49 zeolite synthesized using OMS as the template shows similar crystallinity and purity to that synthesized using pure HMI in conventional process. From the results of NH 3 TPD, N 2 adsorption isotherm, and DTA, it is evident that the MCM 49 zeolite possesses three kinds of acidic centers with different strength, and has a high specific surface area and good thermostability. Furthermore, the MCM 49 zeolite shows good catalytic behavior for the alkylation of benzene with dilute ethylene to ethylbenzene.     

萘与丙烯在脱铝丝光沸石上的烷基化反应

Shape selective alkylation of polynuclear aromatics has begun to receive increasing attention. 2,6 dialkylnaphthalenes are important raw materials for manufacturing high quality polyester fibers and plastics. Understanding of the reaction and the catalysis for conversion of polycyclic aromatic hydrocarbons is needed both from fundamental and practical view points. In this paper, alkylation of naphthalene with propene over a series of dealuminated mordenite with different Si/Al ratios was carried out in an autoclave with an electromagnetical stirrer. Textural property of the dealuminated mordenite was determined by nitrogen adsorption. The amount of the acid sites was measured by NH 3 TPD. The catalytic activity of HM and β shape selectivity for products increased with increasing the Si/Al ratio in HM. Moreover, the selectivity for alkylation with propene was also increased by dealumination treatment. The increase of the catalytic activity was attributed to the formation of mesopores, which significantly promoted the diffusion of reactants and products in mordenite. It was suggested that the increase of β selectivity resulted from the elimination of acid sites from the external surface, and the selectivity for alkylation with propene was improved owing to the creation of the interconnection between 12 ring and 8 rimg channels by dealumination.     

Cubic Mesoporous Aluminosilicate with Primary Structure Units of Zeolite Beta in the Pore Wall

Mesoporous aluminosilicate with cubic ordered structure was synthesized by two-step crystallization,which showed stronger acid sites and more effective activity for catalytic alkylation of 2,4-ditert-butylphenol with tert-butanol than conventional H-AlMCM-48 materials.     

Catalytic Synthesis of Hexyl-naphthalene over H-type Zeolites

H-type zeolites（ HY, Hβ, and HM） were synthesized and characterized by XRD, NH3-TPD, and Py-IR. Selectively catalytic alkylation of naphthalene with n-hexanol to hexyl-naphthalene over the zeolites was carried out. The experimental results show that the catalytic activities of the zeolites are mainly determined by their acid properties and pore structures. The larger the pore diameter is, the higher the catalytic activity is. NH3-TPD profiles show that Hβ and HM have lower acid strengths than HY. HY has both the highest activity and highest selectivity for the hexylnaphthalene. Higher reaction temperatures and longer reaction time are beneficial to the production of β-hexyl-naphthalene over the HY zeolite.     

Acidity effects of Hβ zeolite on olefin alkylation of thiophenic sulfur in gasoline

Olefin alkylation of thiophenic sulfur process was carried out in model gasoline, using Hβ zeolites with different Si/Al2 ratios as catalysts. In particular, the influence of acid properties of Hβ zeolites on its catalytic ability for the thiophene alkylation, xylene alkylation and hexene oligomerization was investigated. The results showed that the acidity of the Hβ zeolite was increased with the decrease of Si/Al2 ratio, but its catalytic ability was not always increased. In fact, it reached the maximal catalytic ability at Si/Al2 ratio of 66, and under the reaction conditions of 60 ℃, 1.5 MPa, WHSV 3.0 h^-1 and time on stream 2 h. At the ratio, the conversion of thiophene, xylene, and oligomerized hexene were 96.6%, 2.7% and 2.8%, respectively. An optimal Si/Al2 ratio exists for the catalytic performance of Hβ zeolite. By investigating the coke deposition of the used Hβ zeolite catalysts, it has been found that the optimal Si/Al2 ratio is attributed to the combined effect of the carbocation activation capability and the hydrogen transformation capability of the Hβ zeolite catalyst.     

Synthesis and Characterization of Benzimidazolium Salts as Novel Ionic Liquids and their Catalytic Behavior in the Reaction of Alkylation

A new series of ionic liquids have been prepared containing benzimidazolium cation (abbreviated as Bim). These salts were characterized by DSC, NMR, elemental analysis and thermogravimetric analysis. They showed different properties compared to imidazolium cation due to the introduction of benzene ring. The alkylation of benzene/diphenyl ether with 1-dodecene was carded in C4eBimBr-AlCl3 ionic liquids showing high catalytic activity when the mole ratio of C4eBimB:AlCl3 was 1:2.     

Polystyrene-supported Phenol/DMAP： an Efficient Binary Catalyst System for CO2 Fixation to Give Cyclic Carbonates

Polystyrene-supported phenol （PS-PhOH） was successfully synthesized by alkylation reaction of phenol with 2% DVB cross-linked chloromethylated polystyrene and characterized by IR spectra and elemental analysis. In conjunction with an organic base such as DMAP, DBU, triethylamine （Et3N）, diethylamine （Et2NH） or pyridine, the PS-PhOH could effectively catalyze the coupling reaction of carbon dioxide with epoxides to give cyclic carbonates in high yield and selectivity under mild conditions. The binary catalyst system of the PS-PhOH/DMAP was found to be the most active. The influence of reaction temperature, carbon dioxide pressure and reaction time on the yield of product was carefully investigated. The PS-PhOH could be recycled by simple filtration for at least up to ten times without loss of catalytic activity.     

Synthesis and Characterization of Novel Layered Lithium Sodium Silicate （Silinaite） and the Mesoporous Materials from Silinaite

Novel layered silinaite has been synthesized using an aqueous mixture of water glass, LiOH and NaOH under hydrothermal crystallization. Subsequently transformation of silinaite into mesoporous materials (SDM) was achieved at mild condition using cetyltrimethylammonium bromide as structure-directing agents. The resulting samples were characterized by XRD, SEM, FTIR nitrogen adsorption-desorption isotherms and catalytic performance in bulky molecular involved reaction. The results revealed that synthesized mesoporous materials derived from the silinaite exhibited an ordered hexagonal crystal structure with average pore diameter 2.7 nm and BET surface area 817m2/g. The SDM-supported ZnCl2 catalyst, prepared by impregnation-evaporation method, retained the mesoporous structure and showed high selectivity in alkylation of benzene with benzyl chloride.     

MCM-22型分子筛的合成及其用于生产异丙苯的催化性能

MCM-22 molecular sieve was first reported by Rubin et al[1] in Mobil Company.Similar to ZSM-5 zeolite, MCM-22 belongs to the category of medium pore zeolites.However, it possesses unique structural features[2] that have not been demonstrated before. The structure of MCM-22 was resolved by Mobil scientists using high resolution microscopy and X-ray diffraction analysis. It is found that MCM-22 consists of two independent and non-interconnecting channel systems, each accessible through 10-ring apertures. One of these pore systems is composed of uniform circular 10-ring pores about 0.6 nm. The other is composed of 12-ring egg-shaped supercages with inner free diameter of 0.71 nm and inner height of 1.82 nm. Usually the zeolite crystallizes as thin sheets or plates of stocked layers. Therefore, MCM-22 has been actively studied and this peculiar zeolite may have potential applications in the petrochemical and petroleum industries in the near future, including reactions such as disproportionation[3], catalytic cracking of hydrocarbons[4], aromatic/ethylene alkylation[5], isoalkane/olefins[6] and methanol/olefins alkylation[7] etc.     

Asymmetric catalytic anhydride openings via carbon-based nucleophiles

The asymmetric desymmetrization of cyclic anhydrides via the addition of carbon-based nucleophiles has been the focus of considerable levels of interest because it leads to optically active products. Over the past 20 years, a variety of different catalytic asymmetric alkylation reactions have been developed for the desymmetrization of cyclic anhydrides using different metal reagents as nucleophiles and using chiral ligands. The purpose of this review is to provide an overview of significant developments in this field. ~ 2013 Fen-Er Chen. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

H3PW12O40/mpg‐C3N4 as an efficient and reusable catalyst in the alkylation of o‐xylene and styrene

A heterogeneous catalyst (HPW/mpg‐C₃N₄) for the alkylation of o‐xylene and styrene reaction was acquired by the immobilization of phosphotungstic acid (HPW) on mesoporous graphitic carbon nitride (mpg‐C₃N₄) through electrostatic interaction. The results of Fourier transform infrared spectroscopy (FT‐IR), X‐ray powder diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) proved that HPW was successfully immobilized on the protonated mpg‐C₃N₄ by electrostatic interaction. The textural properties and morphology of HPW/mpg‐C₃N₄ were characterized by N₂ adsorption–desorption, scanning electron microscopy (SEM). Among them, 40% HPW/mpg‐C₃N₄ displays the best catalytic performance in the alkylation reaction with 91.8% yield and 96.5% selectivity to 1, 2‐diphenylethylane. Moreover, protonated mpg‐C₃N₄ not only displays as a support to facilitate great dispersion of HPW but also promotes the alkylation product diffusion effectively. Besides, the HPW/mpg‐C₃N₄ catalyst could be recycled easily without significant loss of catalytic activity, which is demonstrate by the recyclability of HPW/mpg‐C₃N₄ catalyst test.     

The “Borrowing Hydrogen Strategy” by Supported Ruthenium Hydroxide Catalysts: Synthetic Scope of Symmetrically and Unsymmetrically Substituted Amines

The N‐alkylation of ammonia (or its surrogates, such as urea, NH₄HCO₃, and (NH₄)₂CO₃) and amines with alcohols, including primary and secondary alcohols, was efficiently promoted under anaerobic conditions by the easily prepared and inexpensive supported ruthenium hydroxide catalyst Ru(OH)_x/TiO₂. Various types of symmetrically and unsymmetrically substituted “tertiary” amines could be synthesized by the N‐alkylation of ammonia (or its surrogates) and amines with “primary” alcohols. On the other hand, the N‐alkylation of ammonia surrogates (i.e., urea and NH₄HCO₃) with “secondary” alcohols selectively produced the corresponding symmetrically substituted “secondary” amines, even in the presence of excess amounts of alcohols, which is likely due to the steric hindrance of the secondary alcohols and/or secondary amines produced. Under aerobic conditions, nitriles could be synthesized directly from alcohols and ammonia surrogates. The observed catalysis for the present N‐alkylation reactions was intrinsically heterogeneous, and the retrieved catalyst could be reused without any significant loss of catalytic performance. The present catalytic transformation would proceed through consecutive N‐alkylation reactions, in which alcohols act as alkylating reagents. On the basis of deuterium‐labeling experiments, the formation of the ruthenium dihydride species is suggested during the N‐alkylation reactions.     

N‐chloro amides,lactams, carbamates,and imides. New classes of initiators for the metal‐catalyzed living radical polymerization of methacrylates

Metal‐catalyzed living radical polymerization of methyl methacrylate initiated with N‐chloro amides (N‐chloro N‐ethyl propionamide, N‐chloro benzanilide, N‐chloro methylbenzamide, and N‐chloro acetanilide), lactams (N‐chloro caprolactam and N‐chloro 2‐pyrrolidinone), carbamates or urethanes (N‐chloro ethylcarbamate or N‐chlorourethane), imides (N‐chloro phtalimide, N‐chloro succinimide, trichloroisocyanuric acid, and N‐chloro saccharin) and catalyzed with the self‐regulated catalytic system Cu₂S/2,2′‐bipyridine is reported. The initiation efficiency of these initiators is determined by their structure. Regardless of the initiator efficiency, in all cases, poly (methyl methacrylate) with narrow molecular weight distribution and functionalized chain‐ends was obtained. These new classes of initiators open new strategies for the functionalization of polymer chain‐ends and for the synthesis of complex architectures by graft copolymerization initiated from N‐chloro proteins, aliphatic, aromatic and semiaromatic polyamides, and polyurethanes. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5283–5299, 2005     

以手性相转移催化剂为配体的单分子Cu (II)配合物及其不对称催化反应

在加热条件下,手性相转移催化剂氯化- N -（4-乙烯基苄基）辛可尼定（L1）与氯化铜在2-丁醇中反应,可得到一个单一手性的二价铜单分子配合物 N -（4-乙烯基苄基）辛可尼定三氯化铜(1)。配合物（1）和配体(L1)都可用于催化 N -（二苯基亚甲基）氨基乙酸叔丁基酯（3）烷基化反应,催化结果表明：使用配合物N-（4-乙烯基苄基）辛可尼定三氯化铜的反应对映体选择性比使用配体的更高,配合物催化能力的提高可能与配合物中喹啉环的N原子与铜配位、分子刚性增加有关。     

Secondary Amine‐Catalyzed Asymmetric γ‐Alkylation of α‐Branched Enals via Dienamine Activation

The direct and enantioselective γ‐alkylation of α‐substituted α,β‐unsaturated aldehydes proceeding under dienamine catalysis is described. We have found that the Seebach modification of the diphenyl‐prolinol silyl ether catalyst in combination with saccharin as an acidic additive promotes an S_N1 alkylation pathway, while ensuring complete γ‐site selectivity and a high stereocontrol. Theoretical and spectroscopic investigations have provided insights into the conformational behavior of the covalent dienamine intermediate derived from the condensation of 2‐methylpent‐2‐enal and the chiral amine. Implications for the mechanism of stereoinduction are discussed.     

The catalytic performance study of polymerized ionic liquid synthesized in different conditions on alkylation of o‐Xylene with styrene

In this work, a series of novel acidic polymerized ionic liquids were used as heterogeneous catalyst for alkylation of o‐Xylene with styrene. And the effect of the amount of initiator and the type of acid used for ion exchange on catalyst structure and the catalytic performance of catalysts for alkylation were studied thoroughly. The experiment results show: when the percentage of the amount of initiator in the total material is 3%, the polymerized ionic liquid catalyst MPM‐SO₃H‐[C₃V][SO₃CF₃] has the most uniform with a specific surface area of 97.30 m²/g and a pore volume of 0.35 cm³/g. Benefiting from the unique structure features, MPM‐SO₃H‐[C₃V][SO₃CF₃] manifested an excellent catalytic performance for alkylation of o‐Xylene with styrene, along with the conversion of styrene was 96.8% and the yield of 1‐Phenyl‐1‐ortho‐xylene ethane was 94.7%. Therefore, this work provides a novel reference to the synthesis of polymerized ionic liquids and clearly explains the advantage of novel acidic polymerized ionic liquids on alkylation.     

Microwave syntheses of poly(ε‐caprolactam‐co‐ε‐caprolactone)

Microwave irradiation was applied to synthesize poly(ε‐caprolactam‐co‐ε‐caprolactone) directly from the anionic catalyzed ring opening of two cyclic monomers, ε‐caprolactam and ε‐caprolactone using a variable frequency microwave furnace, programmed to a set temperature and controlled by a pulsed power on–off system. Dielectric properties of ε‐caprolactam, ε‐caprolactone, and their mixture were measured in the microwave range from 0.4 to 3 GHz, showing that both ε‐caprolactam and ε‐caprolactone exhibited effective absorption of microwave energy to induce a fast chemical reaction. The microwave induced anionic copolymerization of ε‐caprolactam and ε‐caprolactone generated copoly(amide‐ester)s in yields as high as 70%. Conventional thermal and microwave copolymerization studies were also conducted for comparison with the microwave results. These studies demonstrated that an effective and efficient microwave method to copolymerize ε‐caprolactam with ε‐caprolactone in higher yield, higher amide content, and higher T_g 's, relative to the thermal process, has been developed. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1379–1390, 2000     

Asymmetric Aldol Reactions in Caprolactam?Quaternary Ammonium Salt Coordination Ionic Liquid Catalyzed by L‐Pro‐L‐Trp

A direct asymmetric aldol reaction of aldehydes and acetone catalyzed by L ‐Pro‐L ‐Trp was performed in β‐caprolactam? quaternary ammonium salt coordination ionic liquid media in the presence of N‐methylmorpholine (NMM) in high yield and with good enantioselectivity. The approach has the advantages of simple product isolation, and reusable catalyst and coordination ion liquids.     

Practical Synthesis of p‐Aminophenethylspiperone (NAPS), a High‐Affinity,Selective D2‐Dopamine Receptor Antagonist

Because attempts to scale up the published synthetic preparation of p‐aminophenethylspiperone (NAPS) by N‐alkylation of spiperone with 4‐nitrophenethyl bromide followed by reduction gave poor yields and difficulties during purification, an alternative synthetic approach has been developed. Use of 4‐(N‐tert‐butyloxycarbonyl) aminophenethyl bromide to alkylate spiperone followed by the Boc group deprotection gave NAPS in 56% yield. This procedure provides an improved and efficient synthesis of the important high‐affinity, selective D₂‐dopamine receptor antagonist NAPS.