化学异构法生产塔格糖的研究

以半乳糖为原料,研究了半乳糖的化学异构法生产塔格糖的工艺参数,确定了异构反应的最佳条件为:选用CaO作为异构剂,最佳用量为每克半乳糖0.375gCaO,半乳糖的最佳浓度为18.75%,反应温度为20℃,反应时间为2h,中和用磷酸调节pH至5.8,得到塔格糖的含量最高可达到74.58%。

A Convenient Synthesis of Trans and Cis-3, 4′, 5-trihydroxystilbene

Aim To synthesize trans and cis-3, 4′, 5-trihydroxystilbene by a new convenient route. Methods The reaction of 3, 5-dimethoxybenzaldehyde （3） and 4-methoxy phenylacetonitrile （4） formed the stilbene skeleton. After hydrolyzation, decarboxylation, and demethylation, we obtained trans-3, 4′, 5-trihydroxystilbene （resveratrol）, which can be converted to its cis-isomer by photochemical isomerization. Results Starting from 3 and 4, trans and cis-3, 4′, 5-trihydroxystilbene were synthesized, respectively. Conclusion A facile method for the synthesis of trans and cis-hydroxystilbenes from readily available materials was established.

Quantum Chemistry and QSAR Studies of Optical Isomers of 3-Methylfentanyl and Ohmefentanyl

The analgesic activities of four 3-methylfentanyl and eight ohmefentanyl optical isomers are very different. In seeking for the reason why a small change in structure leads to such a great difference in activity, we carried out quantum chemistry and QSAR investigations on these compounds. It was found that the spatial relationship between 3-methyl group and the anilidophenyl was most important. Other factors such as the net atomic charge on carbonyl oxygen and the configuration of 1-(-hydroxy also influenced the activities. PLS method was used for the construction of QSAR model. Using only 3 latent variables the correlation and predictive ability were quite satisfactory.

甘露醇在化工中的开发应用

甘露醇（D-mannitol），又名己六醇，木蜜醇，是山梨醇的同分异构体，为白色斜方系晶体或结晶性粉末，相对密度1.489(20/4℃），熔点165～170℃，沸点290～295℃，（在0.4～0.67KPa），折射率1.3330(25℃），比旋光度[α]^20D-0.04℃（10%水溶液），渗透压较大，热值低为8.63kj/g。易溶于水，溶解度22g/100g H2O（25℃），20%的水溶液pH为5.5～6.5，微溶于甲醇、乙醇和乙醚。

One-pot synthesis and structural characterization of urea-isobutyraldehyde-formaldehyde resin

Urea-isobutyraldehyde-formaldehyde (UIF) resin was synthesized from urea, isobutyraldehyde, and formaldehyde using sulfuric acid as a catalyst by one pot method. The effects of molar ratios of isobutyraldehyde to formaldehyde (n(I)/n(F)) and aldehyde to urea (n(A)/n(U)) on the yield, hydroxyl value (vs KOH) and softening point of the resin were investigated. The structure of the resin was characterized by FT-IR, 1H-NMR and 13C-NMR. The results show that when the molar ratio of urea to isobutyraldehyde to formaldehyde (n(U)/n(I)/n(F)) is 1.0/3.0/3.0, the yield UIF resin is 67.1%, and the softening point and hydroxyl value are 88 ℃ and 37 mg/g, respectively. The FT-IR, 1H-NMR and 13C-NMR results show that the lactam is formed by aminomethylation from urea, isobutyraldehyde, and formaldehyde.

Structural Dynamics of 3-Dimethylamino-2-methyl-propenal in S2（ππ^＊） State

The photophysics of 3-dimethylamino-2-methyl-propenal （DMAMP） after excitation to the S2 （ππ^＊） electronic state was studied using the resonance Raman spectroscopy and complete active space self-consistent field method calculations. The transition barriers of the ground state tautomerization reactions between DMAMP and its three isomers were determined at B3LYP/6-311＋＋G（d,p） level of theory. The vibrational spectra were assigned. The A- band resonance Raman spectra were obtained in acetonitrile with excitation wavelengths in resonance with the first intense absorption band to probe the structural dynamics of DMAMP. The B3LYP-TD computation was carried out to determine the relative A-band resonance Raman intensities of the fundamental modes, and the result indicated that the vibronic-coupling existed in Franck-Condon region. Complete active space self-consistent field （CASSCF） calculations were carried out to determine the excitation energies of the lower-lying singlet and triplet excited states, the conical intersection points and the intersystem crossing points. The A-band short-time structural dynamics and the corresponding decay dynamics of DMAMP were obtained by analysis of the resonance Raman intensity pattern and CASSCF computations. It was found that a sudden de-conjugation between C1=O6 and C2=C3 occurred at the Franck-Condon region of the S2（ππ^＊） state, while the enhancement of the conjugation interaction between C3 and N（CH3）2, and between C1 and C2 evolutions shortly after the wavepacket leaves away the Pranck-Condon region via the excited state charge redistribution. The de-conjugation interaction between C1=O6 and C2=C3 made the rotation of C3=N（CH3）2 group around the C2-C3 bond much easier, while the enhanced conjugation between C1 and C2, and between C3 and N（CH3）2 made the rotation around the C1-C2 bond and C3-N5 more difficult. It was revealed that the initial structural dynamics of DMAMP was predominantly towards the CI-I（S2/S0） point, while the opportunities towards either CI-2（S2/S0） or CI-3（S2/S0） point were negligible. Two decay channels of DMAMP from S2,FC（ππ^＊） to So or Tl,min via various CIs and ISCs were proposed.

Theoretical Study on the Stable Structures and Aromaticities for Pnictogen Dianionic Sb4^2-, Bi4^2-, and （SbBi）2^2- Clusters

Through the theoretical calculation of structural optimization, vibrational frequencies and atomization energies with one method of density functional theory （B3LYP） and two post- Hartree-Fock approaches （MP2, CCSD（T））, several stable isomers for new three pnictogen dianionic Sb4^2-, Bi4^2-, and （SbBi）2^2- species were determined. For two homoatomic Sb4^2- and Bi4^2- species, there are three stable isomers： square （D4h）, roof-shaped （C2v-1）, and C2v-2 structure with the square isomer being the ground state. For the heteroatomic dian- ionic （SbBi）2^2- species, there are also three stable isomers： rhombus （D2h）, roof-shaped （C1）, and C2v structures with the rhombic isomer being the ground state. The calculated NICS values show that nucleus-independent chemical shifts （NICS） values of roof-shaped isomers for Sb4^2-, Bi4^2-, and （SbBi）2^2- species are all negative, consequently indicating that these roof-shaped isomers possess aromaticities. NICS values for the planar ring isomers are all positive, suggesting that these three planar ring isomers have antiaromatic characters. The aromaticity for the two stable roof-shaped and square isomers are preliminarily explained and discussed with MO analysis.

Carbcations Chemistry： β-Methyl Shift--A New Rearrangement of the Carbcations Bridged Alicyclic Hydrocarbons

Results of researches on study of the kinetics and isomerization mechanism of the alkyladamantanes in the presence of the heterogeneous catalysts of the acid type are considered as detection and experimental proof of a new intramolecular rearrangement of the carbcations bridged alicyclic hydrocarbons--2,4-moving of the methyl groups （β-methyl shift）. The proof of realization of such rearrangement is direct and primary formation 1,4-dimethyladamantane from 1,2-dimethyladamatane, passing a formation stage of the thermodynamic much stable 1,3-dimethyladamantane; direct formation 1,3,6-trimethyladamantane from 1,3,4-trimethyladamantane, excepting a formation stage 1,3.5-trimethyladamantane, and also other isomers which formation is impossible to explain by means of known 1,2-methyl shift （a-methyl shift）.

A Heterogeneous Information Fusion Deep Reinforcement Learning for Intelligent Frequency Selection of HF Communication

The high-frequency(HF) communication is one of essential communication methods for military and emergency application. However, the selection of communication frequency channel is always a difficult problem as the crowded spectrum, the time-varying channels, and the malicious intelligent jamming. The existing frequency hopping, automatic link establishment and some new anti-jamming technologies can not completely solve the above problems. In this article, we adopt deep reinforcement learning to solve this intractable challenge. First, the combination of the spectrum state and the channel gain state is defined as the complex environmental state, and the Markov characteristic of defined state is analyzed and proved. Then, considering that the spectrum state and channel gain state are heterogeneous information, a new deep Q network(DQN) framework is designed, which contains multiple sub-networks to process different kinds of information. Finally, aiming to improve the learning speed and efficiency, the optimization targets of corresponding sub-networks are reasonably designed, and a heterogeneous information fusion deep reinforcement learning(HIF-DRL) algorithm is designed for the specific frequency selection. Simulation results show that the proposed algorithm performs well in channel prediction, jamming avoidance and frequency channel selection.

Structures of Silk Fibers Grafted with Hexafluorobutyl Methacrylate

The relationship between the graft yield and the effect of hexafiuorobutyl methacrylate graft treatment on the structural changes of the silk fibers was studied on the basis of the results of scanning electron micrograph photographs （SEM）, infrared spectroscopy （IR）, Raman spectrum, wide-angle X-ray diffraction patterns （WAXD）, nuclear magnetic resonance（NMR） and amion acid analysis. The results showed that the crystalline regions of grafted fibers were hardly affected and the fiber fission occurred on the cross sections of grafted fibers. The surface of fibers was covered with a high polymer film. The Raman spectrum showed there was little change in the conformation of grafted fibers which mainly remained β-sheet conformation. The IR of the grafted silk fibers showed new absorption of bands occurred which belonged to the stretching-vibrationabsorption-peak bands of Vo-o and VC-F of aliphatic ester species. The CF3-, -CF2- and -CFH- grafted silk macromodecul were verified in the NMR spectrum. The amion acid analysis indicated fluoride monomers were inclined to graft with TYR, ARG and CLU silk fibers.

Heterogeneous genetic architecture by gender for precision medicine of cardiovascular disease

It is well-known that gender differences exist in the onset, progression, and prognosis of cardiovascular diseases （CVDs）, and that risk factors such as high blood pressure and lipid profiles vary between men and women, Cur- rently, sex differences are stressed as important variables to take into account when examining the etiology of CVD. Genome-wide association studies of CVD have employed the sex as a covariate in their analytical models, but generally disregarded potential genetic heterogeneity （GHS） attributable to sex.

Accurate Quantum Dynamics of the Simplest Isomerization System Involving Double-H Transfer

We perform accurate quantum dynamcs calculations on the isomerization of vinylidene-acetylene.Large-scale parallel computations are accomplished by an efficient theoretical scheme developed by our group,in which the basis functions are customized for the double-H transfer process.The A_(1)' and B_(2)'' vinylidene and delocalization states are obtained.The peaks recently observed in the cryo-SEVI spectra are analyzed,and very good agreement for the energy levels is achieved between theory and experiment.The discrepancies of energy levels between our calculations and recent experimental cryo-SEVI spectra are of similar magnitudes to the experimental error bars,or≤30 cm^(-1) excluding those involving the excitation of the CCH_(2) scissor mode.A kind of special state,called the isomerization state,is revealed and reported,which is characterized by large probability densities in both vinylidene and acetylene regions.In addition,several states dominated by vinylidene character are reported for the first time.The present work would contribute to the understanding of the double-H transfer.

Ab initio Study on Structures and Isomerization of Magnesium Fluorosilylenoid H2SiFMgF

The structures and isomerization of magnesium fluorosilylenoid H2SiFMgF were investigated by ab initio molecular orbital theory. Four equilibrium structures and three isomeric transition states were located and fully optimized at the B3LYP/6-31G（d,p） and G3MP2B3 levels, respectively. Based on the B3LYP/6- 31G（d,p） optimized geometries, harmonic frequencies of various structures were obtained and 29Si chemical shifts were calculated. The solvent effects were investigated by means of the polarizable continuum model using THF as a solvent at B3LYP/6-31G（d,p） level. Isomerization paths for isomers were confirmed by intrinsic reaction coordinate calculations. The calculated results show that tetrahedral structure has the lowest energy and is the most stable; tetrahedral, three-membered ring, and p-complex structures are suggested to be the experimentally detectable ones; and a-complex structure has the highest energy and will not exist.

Direct Z-scheme photochemical hybrid systems:Loading porphyrin-based metal-organic cages on graphitic-C_(3)N_(4) to dramatically enhance photocatalytic hydrogen evolution

The rational design of photochemical molecular device(PMD)and its hybrid system has great potential in improving the activity of photocatalytic hydrogen production.A series of Pd6L3 type metal-organic cages,denoted as MOC-Py-M(M=H,Cu,and Zn),are designed for PMDs by combining metalloporphyrin-based ligands with catalytically active Pd^(2+)centers.These metal-organic cages(MOCs)are first successfully hybridized with graphitic carbon nitride(g-C_(3)N_(4))to form direct Z-scheme heterogeneous MOC-Py-M/g-C_(3)N_(4)(M=H,Cu,and Zn)photocatalysts via π-πinteractions.Benefiting from its better light absorption ability,the MOC-Py-Zn/g-C_(3)N_(4) catalyst exhibits high H_(2) production activity under visible light(10348μmol g^(-1) h^(-1)),far superior to MOC-Py-H/g-C_(3)N_(4) and MOC-Py-Cu/g-C_(3)N_(4).Moreover,the MOC-Py-Zn/g-C_(3)N_(4) system obtains an enhanced turn over number(TON)value of 32616 within 100 h,outperforming the homogenous MOC-Py-Zn(TON of 507 within 100 h),which is one of the highest photochemical hybrid systems based on MOC for visible-light-driven hydrogen generation.This confirms the direct Z-scheme heterostructure can promote effective charge transfer,expand the visible light absorption region,and protect the cages from decomposition in MOC-Py-Zn/g-C_(3)N_(4).This work presents a creative example that direct Z-scheme PMD-based systems for effective and persistent hydrogen generation from water under visible light are obtained by heterogenization approach using homogeneous porphyrin-based MOCs and g-C_(3)N_(4) semiconductors.

Heterogeneous dynamic modeling and simulation of an industrial ethylene oxide reactor experiencing catalyst deactivation

This paper investigates steady-state and dynamic simulation of an industrial fixed-bed ethylene oxide reactor. A mathematical heterogeneous one-dimensional model is developed for simulation of reactor performance in the presence of long term deactivation of silver/a-alumina catalyst. In this paper, steady-state model of the reactor is solved and results of steady state simulation are fed to dynamic simulator as initial condition. When results of dynamic simulation are compared with industrial reactor data, it is found that there were good agreements between simulation results and industrial data. The proposed model is also validated by industrial process data for a period of 1100 operating days.

Genesis of H-ZSM-11 Acidity under Hydrogen and Water Vapor Treatment

1. Introduction Zeolites are widely used in acid heterogeneous catalysis [1, 2]. Due to the unique physical and chemical properties ofzeolites, they are widely used in commercial catalytic processes, such as fluidized catalytic cracking, hydrocracking, methanol conversion to gasoline or olefins, ethylbenzene production, xylene isomerization, aromatics hydrogenation [3-9]. Acidity, high thermal stability, and shape selectivity determine the use of zeolites as catalysts in reaction processes through acid mechanisms [ 10].

Two-dimensional SnO_2/graphene heterostructures for highly reversible electrochemical lithium storage

The ever-growing market demands for lithium ion batteries have stimulated numerous research efforts aiming at the exploration of novel electrode materials with higher capacity and long-term cycling stability.Two-dimensional (2D)nanomaterials and their heterostructures are an intense area of study and promise great potential in electrochemical lithium storage owing to their unique properties that result from structural planar confinement.Here we report a microwave chemistry strategy to integrate ultrathin SnO2 nanosheets into graphene layer to construct surface-to-surface 2D heterostructured architectures,which can provide unique structural planar confinement for highly reversible electrochemical lithium storage.The as-synthesized 2D SnO2/graphene heterostructures can exhibit high reversible capacity of 688.5mAh g^-1 over 500cycles with excellent long-term cycling stability and good rate capability when used as anode materials for lithium ion batteries.The present work definitely reveals the advantages of 2D heterostructures featured with a surface-to-surface stack between two different nanosheets in energy storage and conversion devices.

Breaking the periodic arrangement of atoms for the enhanced electrochemical reduction of nitrogen and water oxidation

The development of cost-effective and highperformance electrocatalysts has been increasingly studied to mitigate upcoming energy and environmental challenges.Amorphization and heterointerface engineering have played significant roles in the rational design of electrocatalysts and modulation of their electrocatalytic activities.However,the synergistic effect between amorphization and heterointerfaces has been scarcely reported.As a proof-of-concept attempt,we develop amorphous FeMo(a-FeMo)electrocatalysts with an abundance of heterointerfaces that are composed of amorphous components and evaluate their electrocatalytic performances toward the nitrogen reduction reaction and oxygen evolution reaction(OER).Benefitting from the synergistic effect between the amorphous nature of the a-FeMo electrocatalysts,which offer a high density of active sites,and significant electron redistribution at the heterointerfaces,the electrocatalysts exhibit a high Faradaic efficiency of 29.15%,an elevated yield rate of 71.78μg_(NH_(3)) mg_(cat.)^(-1) h^(-1) with long-term stability at a potential of-0.1V vs.reversible hydrogen electrode and excellent electrocatalytic activity toward the OER.This study provides a promising and effective method for the rational design of low-cost heterogeneous catalysts with desirable efficiency,selectivity,and stability.

Isomerization and rearrangement of boriranes: from chemical rarities to functional materials

Stimuli responsive materials have recently been the subject of tremendous research efforts owing to their numerous potential applications. Although there currently exist many different types of ＂smart＂ materials, those based on photoresponsive transformations are especially attractive. In this review, we focus on a relatively new class of photochromic molecules based on the photochemistry of chelate organoborates, which form intensely colored, base-stabilized boriranes.Recent efforts to exploit the reactivity of these systems are summarized, and future prospects in materials science discussed.

Achieving highly stable Sn-based anode by a stiff encapsulation heterostructure

Rationally designed heterostructures provide attractive prospects for energy storage electrodes by combining different active materials with distinct electrochemical properties.Herein,through a phase separation strategy,a heterostructure of SnO_(2) encapsulated by amorphous Nb_(2)O_(5) is spontaneously synthesized.Insertion-type anode Nb_(2)O_(5) outer shell,playing as reaction containers and fast ionic pathways,physically inhibits the Sn atoms’migration and enhances the reaction kinetics.Moreover,strong chemical interactions are found at the SnO_(2)/Nb_(2)O_(5) interfaces,which ensure the solid encapsulation of the SnO_(2) cores even after 500 cycles.When used for lithium-ion batteries,this heterostructured anode exhibits high cycling stability with a capacity of 626 mAhg^(-1) after 1000 cycles at 2Ag^(-1)(85% capacity retention)and good rate performance with the capacity of 340 mAhg^(-1) at 8Ag^(-1).