Hydrophobic CHA-ZIFs with a junctional trap between cha and d6r cages for adsorption of 2,3-butanediol in aqueous solution

The adsorption and separation of diols from dilute aqueous solution using hydrophobic materials is very challenging due to the strong diol-water hydrogen-bonding interactions. Herein, we screened hydrophobic zeolitic imidazolate frameworks(ZIFs) with chabazite(CHA) topology for separation of 2,3-butanediol(2,3-BDO) and 1,3-propanediol(1,3-PDO), which had junctional and hydrophobic traps matching the two end methyl groups of the 2,3-BDO molecule. Based on CHA-ZIFs with the same small-sized ligand 2-methylimidazole(mIm) and different large-sized ligand benzimidazole derivatives(RbIm),CHA-ZIFs with larger surface areas were obtained by the addition of excess small-sized ligand mIm in the synthesis process. We showed that all of the hydrophobic CHA-ZIFs preferentially adsorbed 2,3-BDO over 1,3-PDO by static batch adsorption and dynamic column adsorption experiments. But ZIF-301 and ZIF-300 with halogen groups exhibited better adsorptive separation performance for 2,3-BDO/1,3-PDO than ZIF-302 with methyl groups. For a typical ZIF-301, its adsorption capacity for 2,3-BDO was 116.4 mg·g^(-1)and selectivity for 2,3-BDO/1,3-PDO was 3.8 in dynamic column adsorption of the binary-component system(2,3-BDO/1,3-PDO: 50 g·L^(-1)/50 g·L^(-1)). Computational simulations revealed that 2,3-BDO preferentially adsorbed in a trap at the junction between the cha and d6r cages of CHA-ZIFs,meaning the strong host-guest interactions. Therefore, the hydrophobic CHA-ZIFs with a junctional trap were promising candidate materials for adsorbing 2,3-BDO, which also provided a new perspective for separating diols in dilute aqueous solutions.

Production of linear alkylbenzene over Ce containing Beta zeolites

Ce-encapsulated Beta zeolite was synthesized by a one-pot hydrothermal method with citric acid complexing Ce in the absence of Na species.Additional citric acid can effectively prevent the deposition of Ce species during the hydrothermal synthesis of zeolites,leading to uniform distribution of Ce cluster in the framework of Beta zeolites.Moreover,the sodium-free synthesis system resulted that the Brønsted acid sites were mainly located on the straight channels and external surface of Beta zeolites,improving the utilization of Brønsted acid sites.In addition,Ce encapsulated Beta zeolites showed enhanced activity and robust stability in the alkylation of benzene with 1-dodecene based on the synergistic effect between Ce species and Brønsted acid sites,which pave the way for its practical application in the production of alkylbenzene.

Tribological and rheological performance of lithium grease with poly-a-olefin and alkyl-tetralin as base oils

A new category of lithium greases was synthesized by using poly-a-olefin(PAO8) and alkyl-tetralin as base oil, where the alkyl-tetralins were synthesized by the alkylation of tetralin and olefins. The influence of thickener concentration, alkyl-tetralin content and type of blend oils on the rheological and tribological performance of lithium grease was investigated. The microstructures of soap fibers were measured to reveal the structure-property correlations. The concentration of thickener and alkyl-tetralin content obviously affect the lubricating performance of lithium grease, while the molecular structure of alkyltetralin has no obvious impact on their properties. It was found that alkyl-tetralin could significantly enhance the thickening ability of PAO8 base oils, and decrease the amount of thickeners by 1.5%(mass).Lithium greases prepared using 20%(mass) alkyl-tetralin as co-base oil exhibited high colloidal stability,excellent rheological behaviors and tribological properties.

Alkyl-tetralin base oils synthesized from coal-based chemicals and evaluation of their lubricating properties

Naphthenic base oil is an important lubricating base oil and very scarce in the global petroleum resources.Herein,a series of alkylated tetralin fluids similar to naphthenic base oils were produced by the alkylation of tetralin and a-olefins(n-hexene,n-octene,n-decene)with ionic liquid Et_3NHCl/AlCl_(3)as the catalyst,where the applied raw materials are totally derived from the coal chemical industry.The product composition could be controlled by adjusting the feeding ratio of tetralin and olefin.The synthetic fluids were evaluated as lubricating base oils to reveal the structure-property correlations.Their principal physicochemical and tribological properties depend on the chain-length of a-olefins and the number of alkyl groups onto the aromatic rings.Bis-(octyl-or decyl-)alkyl tetralin exhibited good properties in terms of viscosity,thermo-oxidation stability and pour point,as well as friction-reducing and anti-wear performance,showing great potential for producing naphthenic base synthetic oils from coal-based chemicals.

Enhanced ortho-selective t–butylation of phenol over sulfonic acid functionalized mesopore MTW zeolites

Novel organo-inorganic hybrid materials(MTW-x-SO_(3)H) have been fabricated by immobilizing 3-mercap topropyltriethoxysilane onto mesopore MTW zeolites, which is treated via a simple oxidation process with hydrogen peroxide as the oxidant to transform sulfhydryl group into sulfonic acid group. The organic sulfhydryl groups are covalently bonded to the external surface of MTW zeolites through the condensation between siloxane arising from organic fragments with silanol groups on the surface of MTW zeolites, the hybrids contain sulfonic acid group within the external surface of MTW zeolites and an opened mesoporous system in the matrix of MTW zeolites, which provide enough accessible Brùnsted acid sites for the alkylation between phenol with tert-butyl alcohol. Through this methodology it's possible to prepare multifunctional materials where the plenty of mesopores are benefit for the introduction of larger numbers of sulfonic acid groups that contributes to activity during reactions, resulting in high activity(>55%) of MTW-4-SO_(3)H and desired selectivity(>56%) of 2-TBP(2-tert-butyl phenol) in the alkylation between phenol with tert-butyl alcohol.

Alkylation of naphthalene with n-butene catalyzed by liquid coordination complexes and its lubricating properties

With the development of coal chemical industry,large amounts of naphthalene and n-butene are produced,and converting them into high value-added products through alkylation has gained particular importance and interest.In this work,liquid coordination complexes(LCCs)were used as acid catalysts for the first time in the naphthalene alkylation reaction under mild conditions to obtain multibutylnaphthalenes with high yield.Various reaction conditions were thoroughly investigated.The LCC consisting of urea and AlCl_(3) showed excellent catalytic performance under optimal reaction conditions,giving 100%conversion of naphthalene and 99.66%selectivity towards multi-butylnaphthalenes.Combining the catalyst properties and catalytic results,a plausible reaction mechanism was proposed.The lubricating properties of the synthesized products were investigated for their potential application as lubricating base oils.The synthesized multi-butylnaphthalenes showed comparable physicochemical properties and tribological performances as the commercial cycloalkyl base oil.

Ethylene glycol purification by melt crystallization:Removal of 2-methoxyethanol impurity

The coal(syngas)-to-ethylene glycol(CTEG),is contaminated with the naughty impurity 2-Methoxyethanol(ME)generated during the hydrogenation stage,which affect the quality of EG for fiber-grade polyester production.Distillation,is the employed separation process in industrial,which makes production complicated because of the heat sensitivity of the impurities system.Melt crystallization has been regarded as an effective technology to obtain high-purity organic compounds based on the melting points difference,which could avoid the problems by heating.In this work,we have explored the feasibility of the static melt crystallization on the separation of EG/ME in a jacketed crystallization tube.The experimental parameters were investigated,which covers crystallization and sweating stage in each step.The results showed that the purity of EG could reach≥99.8%from the binary system studied via the quaternary separation process.

Direct synthesis of a disinfectant with fresh scent of green plants by semi-hydrogenation of alkynol on Pd single-atom catalysts

Alcohol-based disinfectants have protected people in the coronavirus disease 2019(COVID-19)pandemic,but olfactory stimuli of ethanol may evoke unpleasant memories associated with stressful situations in the devastating infectious disease.The smell of ethanol in household cleaning and disinfectant products can be covered up by the fragrance additives,and 3-hexenol is especially appreciated for the characteristic,strong odor of green plants.Industrial production of 3-hexenol relies on the selective hydrogenation of 3-hexyn-1-ol,where Lindlar catalyst is normally used for the superior selectivity.Although achieving such catalytic transformation in ethanol solution seems as a direct way to produce a disinfectant with green aroma,a popular consumer product in the post-COVID era,severe leaching of toxic Pb hinders Lindlar catalyst as a promising candidate.We find that the Fe_(2)O_(3) supported Pd single-atom catalyst is highly selective to fulfill semi-hydrogenation of 3-hexyn-1-ol in 75%ethanol,and the aforementioned household product is readily generated after filtrating the stable,solid catalyst out of reaction solution.Single-atom catalysts have been frequently utilized for fine-chemical synthesis,while in this work they make stunning debut in practical manufacture of daily used products.

Zero-oxidation state precursor assisted fabrication of highly dispersed and stable Pt catalyst for chemoselective hydrogenation ofα,β-unsaturated aldehydes

The chemoselective hydrogenation ofα,β-unsaturated aldehydes is a key strategy for the synthesis of fine chemicals.Herein,we developed an efficient method of depositing Pt particles on FeO_(x)/SBA-15.This strategy is dependent on using a platinumdivinyltetramethyldisiloxane complex(Pt^(0)-DVTMS)as the precursor,which we demonstrate can be removed through a H_(2)-treatment under mild conditions.This,in turn,allowed for the synthesis of catalysts with well dispersed Pt particles.The presence of FeO_(x) species also aided Pt dispersion;when coated onto SBA-15,FeO_(x) strongly interacted with dissociated Pt species,inhibiting both Pt aggregation and metal leaching.Using cinnamaldehyde as a modelα,β-unsaturated aldehyde,it was demonstrated that this catalyst was highly selective towards the unsaturated alcohol and no obvious loss in activity was observed over five recycles.This catalyst was determined to be significantly more effective than an analogous catalyst prepared using chloroplatinic acid as a precursor,evidencing the importance of using the Pt0-DVTMS precursor.We corroborate the excellent catalytic performance to highly dispersed Pt-species,whereby Pt0 and Pt^(2+) play a critical role in activating H_(2) and the C=O bond.This research demonstrates that the Pt precursor can have a significant impact on the physicochemical properties and thus,the performance of the final catalyst.It also evidences how metal support interactions can dramatically influence selectivity in such hydrogenation reactions.This novel catalyst preparation protocol,using a DVTMS ligand for Pt impregnation,offers a facile approach to the design of multi-component heterogeneous catalysts.

Co-templating Ionothermal Synthesis and Crystal Structure of a New Layered Aluminophosphate from a Protic Deep Eutectic Solvent

Protic deep eutectic mixtures are usually composed of organic amine hydrochloride salts and hydrogen bond donors in a specific molar ratio. Ionothermal synthesis of aluminophosphate as an example, herein, was reported for the first time from an urea-based protic eutectic mixture, consisting of diethylammonium chloride （DEACI） and 1,3-dimethyl urea （DMU）. As a result, a new two dimensional aluminophosphate with 4.8-network, [CH3NH3]2[（C2H5）2NH2]Al3（PO4）4, has been successfully synthesized by co-templating the DEA and methylamine in situ generated from the decomposition of DMU in the absence of HF. Compared to alkyl quaternary ammonium salts with more alkyl-group connected with N atom, this kind of organic amine salts are more likely as the struc- ture-directing agents to synthesize aluminophosphates in urea-based deep eutectic mixtures. It was also found that HF is crucial to the phase selectivity, a known compound with chain-like structure was obtained with the single methylamine as a structure-directing agent in the presence of HF. These materials were characterized by powder XRD, SEM, TG-DSC, 13C CP-MAS NMR and CHN analyses.

Solution-Mediated Transformation of a 1D [Zn（Im）（HIm）2（OAc）] Precursor to Several Different 3D Zn（Im）2 Frameworks

1D compound [Zn（Im）（HIm）2（OAc）] was used as a single precursor of metal and imidazole to prepare several 3-dimensional （3D） Zn（Im）2 frameworks by solution-mediated transformation. Specifically, three known topologies, zni, coi and crb （BCT） were obtained using a solution-mediated transformation with CH3OH, DMF and DMA as solvent, respectively. Structural studies by 13C MAS NMR spectroscopy and TG imply that in the transformation process from 1D compound to coi-[Zn（Im）2]·（DMF）x and crb-[Zn（Im）2]·（DMA）x （ZIF-1）, DMF and DMA solvent molecules acted as structure-directing agent and, therefore, were occluded inside the framework, respectively. In contrast, in the formation of zni-[Zn（Im）2], no solvent molecules were present in the frameworks; therefore the transformation from 1 D compound to zni was induced by temperature. Thus, solution-mediated transformation of a single precursor （1 D compound） approach was established for the synthesis of ZIFs.

Ionothermal Synthesis and Structural Characterization of a Novel Open Framework Zinc Diphosphonate with Carboxylate-like Linker

A novel crystalline zinc diphosphonate, （CH3NH3）4Zn2（xbp）2·H2O, denoted as compound 1, was ionothermally synthesized from tetraethyl-p-xylylenebisphosphonate （Yexbp） and Zn（OAc）2 in a protic eutectic mixture with urea/methylamine hydrochloride. Its structure was determined by single-crystal X-ray diffraction data and had a special three-dimensional open framework with rhombic channels. Compound 1 belongs to the monoclinic system （space group C2/c）, with lattice parameters a=22.6876（19）A, b=8.7376（7）A, c=8.1673（9）A, β= 108.146（2）°, V= 1538.5（2） A^3, Z=2. Its structure is totally different from the typical organic pillared structure, only two oxygens of the phosphonate group are coordinated with zinc atoms, and the third oxygen exists in the terminal form, which is similar to the popular dicarboxylate linkers in MOFs. The organic cations [CH3NH3]^＋ of the eutectic mixture played a structure-directing role for constructing this framework and were confined in the pore channels to balance the negative charges resulting from the zinc phosphonate inorganic chains.

New strategy for production of primary alcohols from aliphatic olefins by tandem cross-metathesis/hydrogenation

Primary alcohols are widely used in industry as solvents and precursors of detergents.The classic methods for hydration of terminal alkenes always produce the Markovnikov products.Herein,we reported a reliable approach to produce primary alcohols from terminal alkenes combining with biomass-derived allyl alcohol by tandem cross-metathesis/hydrogenation.A series of primary alcohol with different chain lengths was successfully produced in high yields(ca.90%).Computational studies revealed that self-metathesis and hydrogenation of substrates are accessible but much slower than crossmetathesis.This new methodology represents a unique alternative to primary alcohols from terminal alkenes.