Synthesis and Interface Activity of a Series of Dicarboxylic Cationic Surfactants and a Structure–Efficiency Relationship Study

Quaternary ammonium cationic surfactants are widely used in many fields, but information about the effect of the anion on cationic surfactants is scarce. To study the effect of anions on the surface properties, six dicarboxylic cationic surfactants were prepared, (cetyltrimethylammonium oxalate, CTAO; cetyltrimethylammonium malonate, CTAM; cetyltrimethylammonium succinate, CTASU; cetyltrimethylammonium glutarate, CTAG; cetyltrimethylammonium adipate, CTAA; and cetyltrimethylammonium sebacate, CTASE), and their surface properties were studied, including surface tension, critical micelle concentration, foaming ability and stability, and corrosion inhibition. The results showed that the minimum surface tension followed the order of CTAO<CTAM<CTASU<CTAG<CTAA<CTASE. The foaming ability followed the order of CTAO>CTAM>CTASU>CTAG>CTAA>CTASE. The foaming stability followed the order of CTAM>CTAO>CTASU>CTAG>CTAA>CTASE. At a concentration of 1.0 g L⁻¹, the order of emulsification power of these surfactants was CTASE<CTAO<CTAA<CTAG<CTASU<CTAM, and at 5.0 g L⁻¹, the order was CTASE<CTASU<CTAA<CTAG<CTAO<CTAM. The corrosion inhibition efficiency on mild steel followed the order of CTASE<CTAA<CTAG<CTASU<CTAM<CTAO.     

A New Type of Porous Plug for Blowing Argon in the VHD

In the process of VHD,argon is blown into the molten steel throuht the porous plugs which are mounted in the ladle bottom.A new type of porous corundum plug has been developed for the VHD secondary refining ladle furnace in Fushun Steel Works ,It is found that when the mean grain size of corundum articles decreases from 760 μm tp 650μm ,the physical properties and service life of the plug are the same as that of importedone ,and can be normally used in the VHD process.     

Study of the Dynamic Modes of the Operation of Flowsheets for the Extractive Distillation of a Benzene–Cyclohexane–Toluene Mixture

Theoretical Foundations of Chemical Engineering - This work considers four extractive distillation flowsheets of a benzene–cyclohexane–toluene mixture with different structures: one of...     

A Structure−Activity Relationship Study of Novel Hydroxamic Acid Inhibitors around the S1 Subsite of Human Aminopeptidase N

Aminopeptidase N (APN/CD13) is a zinc-dependent ubiquitous transmembrane ectoenzyme that is widely present in different types of cells. APN is one of the most extensively studied metalloaminopeptidases as an anti-cancer target due to its significant role in the regulation of metastasis and angiogenesis. Previously, we identified a potent and selective APN inhibitor, N-(2-(Hydroxyamino)-2-oxo-1-(3′,4′,5′-trifluoro-[1,1′-biphenyl]-4-yl)ethyl)-4-(methylsulfonamido)benzamide ( 3 ). Herein, we report the further modifications performed to explore SAR around the S1 subsite of APN and to improve the physicochemical properties. A series of hydroxamic acid analogues were synthesised, and the pharmacological activities were evaluated in vitro. N-(1-(3′-Fluoro-[1,1′-biphenyl]-4-yl)-2-(hydroxyamino)-2-oxoethyl)-4-(methylsulfonamido)benzamide ( 6 f ) was found to display an extremely potent inhibitory activity in the sub-nanomolar range.     

Structure–Activity Relationships of Benzoic Acid Derivatives as Antifeedants for the Pine Weevil, Hylobius abietis

Aromatic organic compounds found in the feces of the pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae), have been shown to deter feeding behavior in this species, which is a serious pest of planted conifer seedlings in Europe. We evaluated 55 benzoic acid derivatives and a few homologs as antifeedants for H. abietis. Structure–activity relationships were identified by bioassaying related compounds obtained by rational syntheses of functional group analogs and structural isomers. We identified five main criteria of efficiency as antifeedants among the benzoic acid derivatives. By predicting optimal structures for H. abietis antifeedants, we attempted to find a commercial antifeedant to protect conifer seedlings against damage by H. abietis in regenerating forests. New, highly effective antifeedants are methyl 2,4-dimethoxybenzoate, isopropyl 2,4-dimethoxybenzoate, methyl 2-hydroxy-3-methoxybenzoate, methyl (3,5-dimethoxyphenyl)acetate, and methyl (2,5-dimethoxyphenyl)acetate. Of these, methyl 2,4-dimethoxybenzoate and isopropyl 2,4-dimethoxybenzoate have the highest antifeedant indices of all substances tested and are the best candidates for practical applications in order to protect planted seedlings in the field.     

Structure,Characterization and Anti-Corrosion Activity of the New Metal–Organic Framework [Ag(qox)(4-ab)]

Yellow crystals of the metal–organic framework (MOF), [Ag(qox)(4-ab)] (1) were obtained at room temperature by the reaction of AgNO₃, quinoxaline (qox) and 4-amino benzoic acid (4-aba). A cluster molecule containing two silver atoms, two qox and two 4-ab ligands is considered the basic building block of the structure of 1. A 3D-network structure is created via H-bonds and π–π stacking. MOF 1 was tested as a corrosion inhibitor for C-steel in 1 M HCl solution using potentiodynamic polarization and electrochemical impedance techniques. It was found that 1 is rich with electron donating groups and the π-systems exhibiting high inhibition efficiency. The adsorption of 1 obeyed the Freundlich adsorption isotherm. Polarization curves indicate that 1 is mixed-type inhibitor. Activation parameters were calculated and discussed. The results obtained from EIS and potentiodynamic polarization are in good agreement.     

On the Structure of the Space of States for a Thermal Model of Fluidized-Bed Reactor–Regenerator Units and Control Visualization Principles

Theoretical Foundations of Chemical Engineering - A system of differential equations for the dynamics of thermal states in reactor–regenerator units with finely dispersed catalysts is...     

Investigation of Mixtures of a Co-Based Catalyst and a Cu-Based Catalyst for the Fischer–Tropsch Synthesis with Bio-Syngas: The Importance of Indigenous Water

A series of different mechanical mixtures of a narrow-pore Co/γ-Al₂O₃ catalyst and a Cu-based WGS-catalyst has been investigated in the low-temperature Fischer–Tropsch synthesis (483 K, 20 bar) with a model bio-syngas (H₂/CO = 1.0) in a fixed-bed reactor. The higher the fraction of WGS-catalyst in the mixture, the lower is the Co-catalyst-time yield to hydrocarbons. This is ascribed to a strong positive kinetic effect of water on the Fischer–Tropsch rate of the Co-catalyst, showing the importance of the indigenously produced water, especially in fixed-bed reactors where the partial pressure of water is zero at the reactor inlet. A preliminary kinetic modeling suggests that the reaction order in P $ _{{{\text{H}}_{ 2} {\text{O}}}} $ is 0.3 for the Co/γ-Al₂O₃ catalyst in the range of the studied reactor-average partial pressures of water (i.e., 0.04–1.2 bar).     

A Comparison Study on the Structure and Performance of Mo–V–O and Mo–V–Te–O Catalysts Synthesized Hydrothermally with Ultrasonic Pretreatment for Propane Oxidation

The Mo_1.00V_0.80O _n and Mo_1.00V_αTe_0.17O _n (α = 0.40–1.00) catalysts were prepared hydrothermally with ultrasonic pretreatment for propane partial oxidation. The fabricated catalysts were characterized by BET, XRD, Raman, XPS, EPR, SEM, H₂–TPR, and NH₃-calorimetric techniques. It is revealed that the content of vanadium in the catalysts is crucial for the generation of phase structure essential for good performance. The role of Te in the catalytic system and the effect of ultrasonic treatment during catalyst fabrication on catalyst properties are interpreted based on the characterization and reaction results obtained.     

Study on Adhesion Properties of a Hot-Melt Pressure-Sensitive Adhesive Based on Epoxidized Styrene–Isoprene-Styrene Triblock Copolymers (ESIS) for Transdermal Drug Delivery Systems

Pressure sensitive adhesives are a critical component in transdermal drug delivery systems (TDDS). In this study, styrene-isoprene-styrene triblock copolymers (SIS) was epoxidized with peroxyformic acid generated in situ. The hot-melt pressure sensitive adhesive (HMPSA) of ESIS with hydrogenated rosin, epoxidized soybean oil, and antioxidant was prepared. The structure and properties of ESIS were characterized with infrared spectroscopy and dynamic mechanical analysis (DMA). Water content and water vapor transmission rate on ESIS membranes were determined. The adhesion properties of HMPSA of ESIS were investigated. The experimental results showed that the HMPSA of ESIS was superior to traditional HMPSA of SIS in 180°peel strength when the substrates were polar materials, such as PVC and steel.     

New phosphorus self-assembling ligands for the tandem hydroformylation–Wittig olefination reaction of homoallylic alcohols — A key step for stereoselective pyran synthesis

New self-assembled phosphorus ligands are synthesized and used in the rhodium complex catalyzed hydroformylation–Wittig reaction of homoallylic olefins under optimized condition. A subsequent oxa-Michael intramolecular reaction yields β-pyran derivatives (conversion and diastereoselectivity up to 99%).     

A New Concept for Adhesion Promotion in Metal–Polymer Systems by Introduction of Covalently Bonded Spacers at the Interface

A new concept for molecular interface design in metal–polymer systems is presented. The main features of this concept are the replacement of weak physical interactions by strong covalent bonds, the flexibilization of the interface for compensating different thermal expansions of materials by using long-chain flexible and covalently bonded spacers between the metal and the polymer as well as its design as a moisture-repellent structure for hindering diffusion of water molecules into the interface and hydrolysis of chemical bonds. For this purpose, the main task was to develop plasmachemical and chemical techniques for equipping polymer surfaces with monotype functional groups of adjustable concentration. The establishing of monotype functional groups allows grafting the functional groups by spacer molecules by applying usual wet-chemical reactions. Four processes were favoured for production of monotype functional groups by highly selective reactions: the plasma bromination, the plasma deposition of plasma polymers, the post-plasma chemical reduction of O-functionalities to OH-groups, and the chemical replacement of bromine groups by NH₂-groups. The grafting of flexible organic molecules as spacers between the metal layer and polymer improved the peel strength of the metal. To obtain maximal peel strength of aluminium coatings to polypropylene films and occurrence of cohesive failure in the polypropylene substrate, about 27 OH groups per 100 C-atoms or 6 COOH groups per 100 C-atoms were needed. Introducing C_6–11-aliphatic spacers 1 OH or COOH group per 100 C-atoms contributed about 60% of the maximal peel strength of the Al–PP system, i.e. 2 or 3 spacer molecules per 100 C-atoms were sufficient for maximal peel strength.     

A new exploration on the substantial improvement of rectifying behaviors for a donor–acceptor molecular diode by graphene electrodes

Sandwiching a donor–acceptor molecule between two graphene nanoribbon (GNR) electrodes to construct a particular molecular diode, our calculations from the first-principles method predict that such a configuration can lead to dramatically different and unexpected effects. When the GNR electrodes are semiconducting, the rectifying behaviors for this molecule can be enhanced greatly. The maximum rectification ratio rises sharply with an increase of the bandgap size of GNR electrodes and can reach a value more than 4000 as the bandgap is about 0.8 eV, which is of a very significant improvement as compared with previously investigated results for such a molecule coupled to bulk metal electrodes. Therefore, our studies imply that using graphene with a large bandgap as electrodes might be a novel effective pathway to greatly raise rectifying behaviors of a donor–acceptor molecule.     

A Study of the Acid–Base Properties of Melts in the Na2O–B2O3–SiO2System: I. Composition Joins with a Na2O Content of Less Than 20 mol %

Three composition joins in the Na₂O–B₂O₃–SiO₂system at constant Na₂O contents of 5, 10, and 15 mol % are studied by the high-temperature method of determining oxygen ion exponents pO for oxide melts. It is found that the basicity of melts increases in going from the binary sodium borate system to the sodium silicate system. The acid–base properties of ternary melts are simulated under the assumption that their basicity is determined by the interaction in pseudobinary systems. It is shown that the basicity of the studied melts is governed, to a large extent, by the formation of the Na₂O · B₂O₃· 2SiO₂ternary compound.