Facile synthesis of hierarchical NaX zeolite from natural kaolinite for efficient Knoevenagel condensation

Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals.However,the micropores of zeolites impose diffusion limitations on bulky molecules,greatly reducing the catalytic efficiency.Herein,we explore an economic and environmentally friendly method for synthesizing hierarchical NaX zeolite that exhibits improved catalytic performance in the Knoevenagel condensation reaction for producing the useful fine chemical 2-cyano-3-phenylacrylate.The synthesis was achieved via a low-temperature activation of kaolinite and subsequent in-situ transformation strategy without any template or seed.Systematic characterizations reveal that the synthesized NaX zeolite has both intercrystalline and intra-crystalline mesopores,smaller crystal size,and larger external specific surface area compared to commercial NaX zeolite.Detailed mechanism investigations show that the inter-crystalline mesopores are generated by stacking smaller crystals formed from in-situ crystallization of the depolymerized kaolinite,and the intra-crystalline mesopores are inherited from the pores in the depolymerized kaolinite.This synthesis strategy provides an energy-saving and effective way to construct hierarchical zeolites,which may gain wide applications in fine chemical manufacturing.

OSDA-free synthesis of FeZSM-22 zeolite from natural minerals for n-octane hydroisomerization

A seed-directed approach to synthesizing Fe ZSM-22 zeolite without organic structure directing agent(OSDA)was developed by using Fe-rich diatomite as all aluminum and iron sources.The Fe ZSM-22zeolite with optimal crystallinity and purity can be obtained by systematically adjusting feed composition and synthesis conditions.Characterizations show that Fe ZSM-22 zeolite synthesized with OSDA-free owns high crystallinity,obvious thin needle-shaped morphology and high Bronsted/Lewis acid ratio.Significantly,when used for n-octane hydroisomerization reaction,its derived catalyst exhibits the best catalytic performance reflected by the highest selectivity to C_(8)isomers compared to the two reference catalysts prepared based on a Fe-containing and a Fe-free ZSM-22 synthesized through an OSDA-directed route from natural diatomite and conventional chemicals,respectively.This work provides an alternative route to sustainably synthesizing heteroatomic zeolites with high performance.

NOVEL SYNTHESIS OF LONG MULTI-BLOCK HETEROPOLYMER CHAINS WITH AN ORDERED SEQUENCE AND CONTROLLABLE BLOCK LENGTHS

It had very long been a dream in polymer science to synthesize long multi-block polymer chains with an orderedchain sequence and controllable block lengths. Using ionic or living free radical polymerization or furnishing each end ofpolymer blocks with a reactive functional group, one can only prepare heteropolymer chains with few long blocks, such asdiblock and triblock copolymers. The most plausible result so far was a pentablock copolymer. Recently, using a combinationof polymer physics and synthetic chemistry, we have invented self-assembly assisted polycondensation (SAAP). Thiscommunication reports the results of using this novel. method to connect 10-100 triblock polymer chains together to formlong multi-block heteropolymer chains with an ordered sequence and controllable block lengths.

A facile solvent-free synthesis strategy for Co-imbedded zeolite-based Fischer-Tropsch catalysts for direct gasoline production

A series of Co-imbedded zeolite-based catalysts were synthesized following a facile solvent-free grinding route.The catalytic performance for direct syngas conversion to gasoline range hydrocarbons was compared with their counterpart Co-impregnated zeolite-based catalysts.Successful transformation of solid raw materials to targeted zeolite was confirmed by XRD,SEM,STEM,and N2 physisorption analysis.An in-depth study of acidic strength and acidic site distribution was conducted by NH3-TPD and Py-IR spectroscopy.Acidic strength showed a pivotal role in defining product range.Co@S1,with the weakest acidic strength of silicalite-1 among three types of zeolites,evaded over-cracking of product and exhibited the highest gasoline and isoparaffin selectivity(≈70%and 30.7%,respectively).Moreover,the solvent-free raw material grinding route for zeolite synthesis accompanies several advantages like the elimination of production of wastewater,high product yield within confined crystallization space,and elimination of safety concerns regarding high pressure due to the absence of the solvent.Facileness and easiness of the solvent-free synthesis route together with promising catalytic performance strongly support its application on the industrial scale.

Hydrothermal in situ Ligand Synthesis from 1,10-Phenanthroline-5,6-dione and Characterization of 1D Coordination Polymers [Co(bpdc)(H_2O)_3]·H_2O and [Cu(bpy)V_2O_6]

Hydrothermal treatment of MCl2 （ M = Co or Cu ） , NH4 VO3, and 1,10-phenanthroline-5,6-dione （pdon） resulted in the formation of a duplex coordination polymer [ Co （ bpdc ） （ H2O ） 3 ] · H2O （ bpdc = 2,2＇-bipyridine-3,3＇-dicarboxylate） and a chain-like coordination polymer [ Cu （bpy） V2O6 ] （ bpy = 2,2＇-bipyridine ）. X-ray single-crystal structural analysis shows that under hydrothermal conditions and in the presence of different transition metals, the organic reagent pdon was transformed in situ into bpdc and bpy, respectively. Mechanism of the in situ ligand synthesis reaction has been discussed.

The structure-directing role of heterologous seeds in the synthesis of zeolite

Zeolites have been widely used as catalysts,ion-exchangers,and adsorbents in chemical industries,detergent industry,steel industry,glass industry,ceramic industry,medical and healthfield,and environmentalfield,and recently applied in energy storage.Seed-assisted synthesis is a very effective approach in promoting the crystallization of zeolites.In some cases,the target zeolite cannot be formed in the absence of seed zeolite.In homologous seed-assisted synthesis,the structure of the seed zeolite is the same to that of the target zeolite,while the structure of the seed zeolite is different to that of the target zeolite in the heterologous seed-assisted synthesis.In this review,we briefly summarized the heterologous seed-assisted syntheses of zeolites and analyzed the structure-directing effect of heterologous seeds and surveyed the“common composite building units(CBUs)hypothesis”and the“common secondary building units(SBUs)hypothesis”.However,both hypotheses cannot explain all observations on the heterologous seed-assisted syntheses.Finally,we proposed that the formation of the target zeolite does need nuclei with the structure of target zeolite and the formation of the nuclei of the target zeolite can be promoted by either the undissolved seed crystals with the same CBUs or SBUs to the target zeolite or by the facilitated appropriate distribution of the specific building units due to the presence of the heterologous seed that does not have any common CBUs and SBUs with the target zeolite.

STUDY ON AB-CROSSLINKED POLYMERS Ⅰ. THE SYNTHESIS AND MECHANICAL PROPERTIES OF AB-CROSSLINKED POLYMERS BASED. ON PU/PS

The AB-crosslinked polymers (i.e. ABCP) with polystyrene as chain A and vinyl group blocked prepolymers of polyurethanes (PU) as chain B were synthesized and studied. The results of dynamic mechanical spectrometry (DMS) show that the compatibility between the components A and B can be improved greatly through chemical crosslinking during the formation of ABCPs. This effect is especially pronounced when short chain prepolymers is chosen as one of the components. It is apparent that the degree of crosslinking between the two components plays a major role in determining their compatibility. Copolymerizafion of styrene with maleic anhydride in chain A can improve the compatibility and broaden the damping temperature range. Mechanical properties of the sythesized ABCPs were also studied.

In Situ Synthesis of NaY Zeolite with Coal-Based Kaolin

NaY zeolites were in-situ synthesized from coal-based kaolin via thehydrothermal method. The effects of various factors on the structure of the samples were extensivelyinvestigated. The samples were characterized by N_2 adsorption, XRD, IR and DTG-DTA methods, andthe results show that the crystallization temperature and amount of added water play an importantrole in the formation of the zeolite structure. The 4A and P zeolites are the competitive phasepresent in the resulting product. However, NaY zeolites with a higher relative crystallinity,excluding impure crystals and the well hydrothermal stability, can be synthesized from coal-basedkaolin. These zeolites possess a larger surface area and a narrow pore size distribution, and thismeans that optimization of this process might result in a commercial route to synthesize NaYzeolites from coal-based kaolin.

Hydrothermal Synthesis, Crystal Structure and Photoluminescent Property of a Zinc(II) Coordination Polymer Assembled by Phthalate and 4,4′-Bipyridine

A metal-organic coordination polymer {[Zn（Pht）（4,4＇-bipy）（H2O）2]·2H2O}n （Pht = phthalate, 4,4＇-bipy = 4,4＇-bipyridine） 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Yellow crystals crystallize in the monoclinic system, space group P2/n, a = 7.6346（14）, b = 11.316（2）, c = 10.8133（19） ,A, β = 92.A.A,A.（3）°, V = 933.3（3） A^3, C18H20N2O8Zn, Mr = 457.73, Dc = 1.629 g/cm^3, F（000） = 472, Z = 2,μ（MoKa） = 1.367 mm^-1, the final R = 0.0323 and wR = 0.0821 for 1859 observed reflections （Ⅰ〉 2σ（Ⅰ））. The structure of 1 exhibits a two-dimensional bilayer framework formed by hydrogen bonding interactions. Furthermore, 1 shows yellow photoluminescent property at room temperature.

Hydrothermal Synthesis, Crystal Structure and Photoluminescent Property of a New Isophthalate- bridged Zinc(II) Polymer with One-dimensional Chain Structure: [Zn(ipt)(im)_2]_(2n)·3nH_2O (ipt = Isophthalate, im = Imidazole)

A new metal-organic coordination polymer [Zn（ipt）（im）2]2n·3nH2O 1 has been obtained by using hydrothermal synthesis and characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group P2（1/n） with a = 10.653（3）, b = 17.891（6）, c = 10.743（4）A^°,β= 117.093（5）°, V= 1822.9（10） A^°3, Mr= 413.65, Dc = 1.507 g/cm^3,/t（MoKa） = 1.390 mm^-1, F（000） = 840, Z = 4, the final R = 0.0444 and wR = 0.1066 for 2434 observed reflections （I〉 2σ（I））. Furthermore, compound 1 shows blue photoluminescent property at room temperature.

POROUS MEMBRANE TEMPLATED SYNTHESIS OF POLYMER PILLARED LAYER

The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates tosynthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane pores, and thelayer on the template surfaces. Rigid cured epoxy resin, polystyrene and soft hydrogel were chosen to confirm themethodology. The pillars were in the form of either tubes or fibers, which were controlled by the alumina membrane pore surface wettability. The structural features were confirmed by scanning electron microscopy results.

Hydrothermal Synthesis and Crystal Structure of a Cobalt(II) Coordination Polymer: [Co(C_2O_4)(bix)]_n (bix = 1,4-Bis(imidazol-1-ylmethyl)-benzene)

A new two-dimensional cobalt coordination polymer has been prepared and fully characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. The compound [Co（C2O4）（bix）]n 1 crystallizes in the monoclinic system, space group C2/c, with a = 11.549（3）, b = 15.700（3）, c = 9.260（2） A, β = 102.984（3）°, V = 1636.0（6） A^3, C16HIaCON4O4, Mr= 383.23, Dc = 1.556 g/cm^3, μ（MoKa） = 1.078 mm^-1, F（000） = 780, Z = 4, the final R = 0.0455 and wR = 0.1286 for 1483 observed reflections （I 〉 2σ（I））. Of the compound, the Co center is octahedrally coordinated with oxalate acting as a tetra-dentate ligand coordinated to the cobalt atom and each bix serving as a bridging ligand by employing two N-donors to coordinate with the Co center. An infinite {Co2（C2O4）2}∞ chain is formed along the α axis. Furthermore, the 1D chains are held together via bix ligands to generate a two-dimensional network structure with 1D coronal-like channels （ca. 5.691A × 15.700A）.

Hydrothermal Synthesis and Crystal Structure of a New Three-dimensional Heterometallic Coordination Polymer

A new 3d-4fheterometallic polymer {[Sm2Cu（PDC）2（SO4）2（H20）6]·2H2O}n 1 has been synthesized by Sm2O3, Cu（SO4）2·5H2O and pyridine-3,5-dicarboxylic acid under hydrothermal conditions. The compound crystallizes in triclinic system, space group Pi, with a = 6.352（7）, b = 10.040（10）, c = 10.315（11） A, α = 94.958（14）, β = 95.556（7）, γ = 99.747（14）°, V = 641.7（12）A3, Z = 1, M, = 1030.63, Dc= 2.651 Mg/m3,μ = 5.615 mm-1, F（000） = 491, the final R = 0.0491 and wR = 0.1345 for 2098 observed reflections with I 〉 2σ（I）. The compound is a three-dimensional network structure in which infinite lanthanide-carboxylate chains are linked by [Cu（$04）2]2- metalloligands to form a mixed-metal coordination network.

Hydrothermal Synthesis and Crystal Structure of a Novel Isophthalate-bridged Copper(II) Polymer with Two-dimensional Network Structure: [Cu_2(phen)(ipt)_2]_(2n)·nH_2O (ipt = isophthalate, phen = 1,10-phenanthroline)

A novel metal-organic coordination polymer [Cu2（phen）（ipt）2]2n-nH2O 1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group P21/c with a = 12.338（3）, b = 12.167（3）, c = 18.167（4）A, β= 111.686（14）°, V = 2534.1（10）A^3, C28H18Cu2N2O9, Mr = 653.52, Dc = 1.713 g/cm^3,μ（MoKα） = 1.740 mm^-1, F（000） = 1320, Z = 4, the final R = 0.0443 and wR = 0.0853 for 3543 observed reflections （1 〉 2σ（I））. It exhibits a novel two-dimensional network with tetra-Cu-ipt-as building units.

Urothermal Synthesis and Crystal Structure of a Zn(Ⅱ) Coordination Polymer with a 3-D Supramolecular Structure

A new metal-organic coordination polymer [Zn（hfipbb）（e-urea）]n（1,H2hfipbb = 4,4＇-（hexafluoroisopropylidene）bis（benzoic acid）,e-urea = ethylene urea） has been urothermally synthesized and characterized by elemental analysis and single-crystal X-ray diffraction.The title complex crystallizes in monoclinic,space group P21/c with a = 13.302（4）,b = 10.981（3）,c = 13.804（4） ,β = 93.587（5）°,V = 2012.3（10） 3,C20H14N2O5F6Zn,Mr = 541.72,Z = 4,Dc = 0.447 g/cm3, = 0.328 mm-1,F（000） = 272,R = 0.0340 and wR = 0.1107 for 4528 observed reflections（I 〉2σ（I））.In the structure of compound 1,two Zn（Ⅱ） ions are bridged by two carboxylate groups from two hfipbb ligands to form a dinuclear unit,and each dinuclear Zn（Ⅱ） unit is linked with its two adjacent dinuclear units through four hfipbb ligands into an infinite one-dimensional double-chain.The interesting structural feature of compound 1 is that the one-D double-chains are self-interconnected into a three-D supramolecular structure through hydrogen bonds between the coordinated e-urea molecules and carboxylate oxygen atoms（N1 and O2,N2 and O4）.

Hydrothermal Synthesis and Crystal Structure of a Cadmium(II) Polymer with One-dimensional Chain Structure: [Cd(bpy)(BDC)]_n·nbpy

A metal-organic coordination polymer [Cd（bpy）（BDC）]n·nbpy （bpy = 2,2-bipyri-dine, H2BDC = terephthalic acid） has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG and single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group C2/c with a = 15.723（5）, b = 21.695（5）, c = 7.576（5） A, β = 116.171（7）°, V = 2319.3（18）A^3, C28H20CdN4O4, Mr = 588.88, Dc = 1.686 g/cm^3, μ（MoKα） = 0.987 mm^-1, F（000） = 1184, Z = 4, the final R = 0.0464 and wR = 0.0831 for 1882 observed reflections （Ⅰ〉 2σ（Ⅰ））. It exhibits a three-dimensional network with channels constructed from one-dimensional coordination chains via C–H…O hydrogen bonds and significant aromatic π-π stacking interactions.

Hydrothermal Synthesis and Crystal Structure of a Zinc(II) Polymer with a Two-dimensional Layer Structure: [Zn(pzdc)(phen)]_n·nH_2O

A metal-organic coordination compound formulated as [Zn（pzdc）（phen）]n·nH2O 1 （H2pzdc = pyrazine-2,3-dicarboxylic acid, phen = 1,10-phenanthroline） has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, fluorescence spectrum and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system, space group P21/n with a = 11.607（2）, b = 11.719（2）, c = 13.140（3）A^°, β = 110.707（3）°, V= 1671.9（6）A^°3, C18H12ZnN4O5, Mr= 429.69, De = 1.707 g/cm^3,μ（MoKa） = 1.511 mm^-1, F（000） = 872, Z = 4, the final R = 0.0356 and wR = 0.0853 for 2713 observed reflections （I 〉 2σ（I））. It exhibits an interesting two-dimensional layer structure and shows yellow photoluminescent property at room temperature.

Eco-friendly synthesis of high silica zeolite Y with choline as green and innocent structure-directing agent

Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure‐directing agents(OSDAs),which are chronically hazardous to humans and the environment.It is a growing trend to develop an eco‐friendly and nuisanceless OSDA for zeolite synthesis.Herein,choline is employed as a non‐toxic and green OSDA to synthesize high silica Y zeolite with SiO2/Al2O3 ratios of 6.5–6.8.The prepared Y zeolite samples exhibited outstanding(hydro)thermal stability at ultrahigh temperature owing to the higher SiO2/Al2O3 ratio.The XRF,SEM,29Si‐NMR and 13Na+results suggested that choline plays a structure‐directing role in the synthesis of Y zeolite,while the feed molar fraction of Na+is a crucial determinant for the framework SiO2/Al2O3 ratio and the crystal morphology.

Mixed-solvothermal Synthesis, Crystal Structure and Luminescence of a New Dinuclear Yttrium(Ⅲ) Coordination Polymer with 1-D Wave-like Infinite Chains

A new dinuclear Y（3＋） coordination polymer{[Y2（H2O）2（C（14）H8O4）3（C（12）H8N2）2]·3 H2O}n （1, C（14）H8 O4 = 2,2＇-biphenyldicarboxylate, phen = 1,10-phenanthroline）, has been obtained by means of a mixed-solvothermal method using ethylene glycol and water as solvent. The compound was characterized by elemental analysis, energy-dispersive X-ray spectroscopy（EDS）, IR spectrum and single-crystal X-ray diffraction. The results reveal that 1 belongs to monoclinic system, space group C2/c with a = 24.249（3）, b = 12.069（48）, c = 22.7304（08） A, β = 113.480（7）°, Z = 4, V = 6102（2） A3, Dc = 1.462 g·cm^-3, F（000） = 2728, μ = 1.968 mm（-1）, the final R = 0.0673, w R = 0.1508 and S = 1.085. Its structure can be regarded as a 1-D coordination polymer constructed by Y^3＋ cations, 2,2A-biphenyldicarboxylate, 1,10-phenanthroline and water molecules. The compound not only contains two kinds of organic ligands, but also exhibits interesting wave-like infinite chains and 18-MR windows with the diameter of 4.070（7）A × 5.326（9）A. The structure is further stabilized by means of O–H…O hydrogen bonds and π-π stacking interactions. Furthermore, the luminescent properties（including emission spectrum, CIE chromaticity coordinate and decay curve） of 1 were also investigated in the solid-state at room temperature.

Temperature-controlled Hydrothermal Synthesis of Copper(Ⅰ or Ⅱ) Coordination Polymers via a Variety of Copper Coordination Modes

Two 1D coordination polymers Cu2I（C6N3H4）2（1） and CuⅡ（C6N3H4）2·H2O（2） based on benzotriazole（Bta） were hydrothermally synthesized by controlling the crystallization temperature.Single-crystal X-ray diffraction（XRD） analyses reveal that compound 1 is a 1D tubular structure constructed from two types of 1D chains {―Cu―N=N―N―} n,where the Cu（I） ions adopt linear,triangular,and tetrahedral coordination modes to connect two types of Bta ligands via π-π interaction inside the tubular-like chain.For compound 2,the Cu（Ⅱ） ions assume a quadrilateral coordination mode linking to the Bta ligands to give 1D straight chains,which stacks through π-π interactions to construct a 2D layer structure.Further characterizations including elemental analyses,infrared IR spectra,thermogravimetric（TG） analyses and luminescence properties have been done.