Efficient production of bisphenol-A by utilizing cation-exchange polystyrene resins that are cross-linked by naphthalene or a biphenyl unit

Ion-exchange materials are well known for their utilization in the processes of water treatment,1, 2, 3, 4, 5 demineralization,6, 7 water softening,8, 9, 10 ultra purification of water11, 12 and removal of unwanted ions,13, 14 as well as in chemical processing.15 One ion-exchange material is acidic sulfonated polystyrene-divinylbenzene (DVB) cation-exchange resin, which has an important role in the production of bisphenol-A by participating in an acid-catalyzed condensation reaction between phenol and acetone. Bisphenol-A is a very important raw material for the synthesis of epoxy resins and polycarbonates; thus, >400 000 tons of bisphenol-A have recently been domestically produced

Reactive Oxygen Species and Antioxidative Defense in Chronic Obstructive Pulmonary Disease

The respiratory system is continuously exposed to endogenous and exogenous oxidants. Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation of the airways, leading to the destruction of lung parenchyma (emphysema) and declining pulmonary function. It is increasingly obvious that reactive oxygen species (ROS) and reactive nitrogen species (RNS) contribute to the progression and amplification of the inflammatory responses related to this disease. First, we described the association between cigarette smoking, the most representative exogenous oxidant, and COPD and then presented the multiple pathophysiological aspects of ROS and antioxidative defense systems in the development and progression of COPD. Second, the relationship between nitric oxide system (endothelial) dysfunction and oxidative stress has been discussed. Third, we have provided data on the use of these biomarkers in the pathogenetic mechanisms involved in COPD and its progression and presented an overview of oxidative stress biomarkers having clinical applications in respiratory medicine, including those in exhaled breath, as per recent observations. Finally, we explained the findings of recent clinical and experimental studies evaluating the efficacy of antioxidative interventions for COPD. Future breakthroughs in antioxidative therapy may provide a promising therapeutic strategy for the prevention and treatment of COPD.</p

Efficient production of bisphenol-A by utilizing cation-exchange polystyrene resins that are cross-linked by naphthalene or a biphenyl unit

Ion-exchange materials are well known for their utilization in the processes of water treatment,1, 2, 3, 4, 5 demineralization,6, 7 water softening,8, 9, 10 ultra purification of water11, 12 and removal of unwanted ions,13, 14 as well as in chemical processing.15 One ion-exchange material is acidic sulfonated polystyrene-divinylbenzene (DVB) cation-exchange resin, which has an important role in the production of bisphenol-A by participating in an acid-catalyzed condensation reaction between phenol and acetone. Bisphenol-A is a very important raw material for the synthesis of epoxy resins and polycarbonates; thus, >400 000 tons of bisphenol-A have recently been domestically produced

Regulation of dynamic structure of cyclophanes by their complexation with the porphyrin

Dithia[3.3]metacyclophanes which consist of the pyridine unit connecting to the different positions of the parent cyclophane skeleton have been prepared. Conformational change has been observed for the cyclophane having a 4-substituted pyridine unit by binding to the porphyrin. In contrast the porphyrin binding has no influence on conformational behavior of the cyclophane having a 3-substituted pyridine unit

Regulation of dynamic structure of cyclophanes by their complexation with the porphyrin

Dithia[3.3]metacyclophanes which consist of the pyridine unit connecting to the different positions of the parent cyclophane skeleton have been prepared. Conformational change has been observed for the cyclophane having a 4-substituted pyridine unit by binding to the porphyrin. In contrast the porphyrin binding has no influence on conformational behavior of the cyclophane having a 3-substituted pyridine unit

Gelating Abilities of Two-component System of Catecholic Derivatives and a Boronic Acid.

In the last two decades, various kinds of the low-molecular-weight organogelators (LMOGs) have been investigated in terms of technological applications in various fields as well as their fundamental scientific properties. The process of gelation is generally considered to arise from immobilization of the solvents in the three-dimensional networks formed by the assembly of gelator molecules through weak intermolecular noncovalent interactions. From these points of view a huge number of organogelators have been developed so far. In the course of our research on LMOGs we have noticed a mixture of two gelators could show a different trend in gelation compared to the single gelator. It is well known that the catecholic moiety easily forms cyclic boronate esters with the boronic acid. Thus, we have investigated the two-component system based on cyclic boronate esters formed by the catechols and a boronic acid in terms of the control of gelation capability. Basic gelation properties of the constituent catecholic gelators have also been clarified. The catecholic gelators with the amide unit form no gel by addition of the boronic acid. In contrast, the catecholic gelators with the glutamic acid moiety improve their gelation abilities by mixing with the boronic acid. Furthermore, the gelation ability of the catecholic gelators having the urea unit is maintained after addition of the boronic acid. It has been found that gelation abilities of the catecholic gelators are highly affected by addition of the boronic acid. In terms of practical applications some gels can be obtained by on-site mixture of two kinds of solutions

Investigation of the hardener with latent and rapid curing based on phenol-amine salts for applications to cyanate ester resins.

We have developed the curing agents that have good storage stability for cyanate ester resins. It should be noted that these agents can be given rapid and efficient curing at low temperatures around 100°C. Even though the nucleophilicity was reduced by a phenol-amine salts consisting of basic aliphatic amines and weakly acidic phenols, the curing reaction with the cyanate ester occurred immediately. It means that the control of the curing reaction with cyanate esters is not easy due to the equilibrium between phenol and amine. In order to overcome this difficultly cyanate esters reactivity, the molecular motions suppression by polymer was applied in addition to the phenol-amine salts. The effect of the suppression for hardeners was studied in terms of the storage stability and reactivity to cyanate esters. It has been found out that PSM-EPEDA composed of ethylenediamine-epoxy adducts and novolac phenolic resin exhibits a large storage stability against cyanate esters by its effective suppression of molecular motions accompanied with efficient and rapid curing around 100°C

Formation of Organogel In Situ Based on a Dynamic Imine Bond

A simple approach for creating organogel in situ through formation of a reversible imine bond known as a dynamic covalent bond is described. As the condensations of the glutamate-based amine compounds and salicylaldehyde or 2-hydroxy-1-naphthaldehyde in alcohols such as MeOH, EtOH and propanol as well as DMF proceed, gelation occurs in situ depending on the condition. Addition of a small amount of acid and water to a resultant gel induces its collapse due to returning to the corresponding amines and aldehydes. No such a gelation was observed when combining benzaldehyde or naphthaldehyde

Molecular Structure and Crystal Packing of n-Type Semiconducting Material 3\u27,3\u27-(1,4-Phenylene) bis {2\u27-(4-trifluoromethyl) phenyl} acrylonitrile

The exact molecular structure and the crystal packing of the n-type semiconducting material 3′,3′-(1,4-phenylene)bis{2′-(4-trifluoromethyl)phenyl}acrylonitrile was determined by a single crystal X-ray diffraction with twin treatment technique. The air-stable product was crystallized from dichloromethane-hexane mixed solution. The solid-state structure is the example of a typical π-π stacking with side intermolecular CN–H short contact networks