Note a Kinetic Study of the Photopolymerization of N,N Methylenebisacrylamide Initiated by N‐Bromo‐Succinimide in the Presence and Absence of Isopropyl Alcohol

The photopolymerization of N,N′‐methylenebisacrylamide has been studied with N‐bromosuccinimide as photoinitiator in the presence and absence of isopropyl alcohol (ISP). The rate of polymerization in the presence of ISP was found to be very high, and this is explained on the basis of the relative reactivities of the initiating radicals. A probable mechanism consistent with the observed results is proposed and discussed.     

氮掺杂碳纳米管负载的Ru和Pd催化剂上异丙醇的转化(英文)

Ru and Pd (2 wt%) loaded on pure and on Ndoped carbon nanotubes (NCNTs) were prepared and tested using the isopropyl alcohol decomposition reaction as probe reaction. The presence of nitrogen functionalities (pyridinic, pyrrolic, and quaternary nitrogen) on the nitrogen doped support induced a higher metal dispersion: Pd/NCNT (1.8 nm) Pd/CNT (4.9 nm), and Ru/NCNT (2.4 nm) Ru/CNT (3.0 nm). The catalytic activity of the supports was determined first. Isopropyl alcohol conversion produces acetone on CNTs while on NCNTs it led to both dehydration and dehydrogenation products. At 210 °C and in the presence of air, the isopropyl alcohol conversion was higher on the NCNTs (25%) than on the CNTs (11%). The Pd loaded catalysts were more active and more selective than the Ru ones. At 115 °C, the Pd catalysts were 100% selective towards acetone for a conversion of 100%, whereas the Ru catalysts led to dehydration and dehydrogenation products. The nitrogen doping induced the appearance of redox properties when oxygen is present in the reaction mixture.     

Compounds of the menthane series. Synthesis of unsaturated primary alcohols with the <Emphasis Type="Italic">o</Emphasis>- and <Emphasis Type="Italic">p</Emphasis>-menthane skeletons

Precursors to terpene alcohols of the o- and p-menthane series (o-cimen-7-ol and o- and p-cimen-9-ols) were synthesized, and their reduction with lithium in ethylenediamine was studied. The reduction of o- and p-cimen-9-ols in the presence of isopropyl alcohol selectively afforded the corresponding 1,4-dihydro derivatives. Under analogous conditions, o-cimen-7-ol was converted into a mixture of unsaturated hydrocarbons. The reduction with lithium in ethylenediamine in the absence of isopropyl alcohol in all cases gave mixtures of menthene alcohols.     

Reactions of organic exhausts and the thermal stability of catalysts

The catalytic combustion of various organic compounds has been investigated over noble and non-noble metal catalysts using a fixed bed. It was concluded that the activity order of different organic compounds on a noble metal catalyst, is toluene > 2-butanone > benzene >n-heptane≈isopropyl alcohol > acrylonitrile > cyclohexane. On non-noble metal catalyst, it is isopropyl alcohol > 2-butanone > acrylonitrile > toluene >n-heptane > cyclohexane > benzene. In order to compare the thermal stability of catalysts, the catalytic reaction of toluene has been studied over noble and non-noble metal catalysts which were calcined at various temperatures up to 900°C for 3 h.     

Novel mesoporous solid superacidic catalysts: activity and selectivity in the synthesis of thymol by isopropylation of m-cresol with 2-propanol over UDCaT-4, -5, and -6

The alkylation of m-cresol with isopropyl alcohol in the presence of novel superacidic catalysts named as UDCaT-4, UDCaT-5, and UDCaT-6 was investigated. The catalysts are modified versions of zirconia showing high catalytic activity, stability, and reusability in the presence of water as compared to conventional sulfated zirconia. The objective of the present investigation was to explore the potential of these catalysts in this alkylation of m-cresol with isopropyl alcohol to thymol, which has widescale applications. The reactions were conducted in liquid phase in the temperature range of 433-473 K. Both, O- and C-alkylated products were obtained at lower temperatures, while at higher temperatures, thymol was the main product of the reaction. The catalytic activity increases in the order UDCaT-5 > UDCaT-6 >UDCaT-4 > sulfated zirconia. Thymol could be efficiently obtained with selectivity reaching up to 79% at an isopropyl alcohol conversion of 92% with UDCaT-5. This process can be a replacement for the existing process based on zeolites where high temperature and pressure are required. Synergistic effects of very high sulfur content present (9% S) and preservation of the tetragonal phase in UDCaT-5, in comparison with sulfated zirconia (4% S), were responsible for higher catalytic activity. A systematic investigation of the effects of various operating parameters was accomplished, and a mathematical model is developed to describe the reaction pathway and validated with experimental results. The reaction was carried out without using solvent, and the process subscribes to the principles of green chemistry.     

An Alternative Short Synthesis of 6,10,14-Trimethyl-5E, 9E-Pentadecadiene-2,13-dione

6,10,14-Trimethyl-5E, 9E-pentadecadiene-2,13-dione, a natural marine C₁₈ terpenoid isolated from the brown alga of Cystophora moniliformis, was prepared from available geranylacetone via 4 steps in 35% overall yield by the selective alkylation of the lithium enolate of methyl isopropyl ketone with the correspounding allylic iodide.     

Preparation, photocatalytic activities, and dye-sensitized solar-cell performance of submicron-scale TiO2 hollow spheres

We prepared submicron-scale spherical hollow particles of anatase TiO2 by using a polystyrene-bead template. The obtained particles were very uniform in size, with a diameter of 490 nm and a shell thickness of 30 nm. The Brunauer-Emmett-Teller surface area measurements revealed a large value of 70 m2/g. The photocatalytic property was investigated by the complete decomposition of gaseous isopropyl alcohol under UV irradiation. It was indicated that the activity of the hollow spheres was 1.8 times higher than that of the conventional P25 TiO2 nanoparticles with a diameter of 30 nm. Furthermore, we fabricated a dye-sensitized solar cell (DSC) using an electrode of the TiO2 hollow spheres, and examined the photovoltaic performance under simulated sunlight. Although the per-area efficiency was rather low (1.26%) because of a low area density of TiO2 on the electrode, the per-weight efficiency was 2.5 times higher than those of the conventional DSCs of TiO2.     

Kinetics of 2,2′-Bipyridyl-Catalyzed Oxidation of Isopropyl Alcohol with Chromic Acid

2,2′-Bipyridyl and some substituted compounds catalyze effectively the oxidation of isopropyl alcohol by chromic acid. The reaction is first order in chromium(VI), alcohol and 2,2′-bipyridyl; it is first order in hydrogen ions at high acidity and slightly alters to second order at low acidity. The proposed mechanism shows that the rate-limiting step is mainly the decomposition of a termolecular complex to products. However, at low acidity, the formation step of this complex is a little less reversible and hence somewhat rate-limiting. Electron-donating substituents at the 4-position enhance the catalytic activity. Electron-withdrawing substituents at the 4- and 2-positions diminish the reaction rates by electronic and steric factors.     

Influence of solvent structure on the aquation of K‐chloro(diethylenetriamine)(ethylenediamine) cobalt(III) ion in water and mixed aqueous solvents

The aquation of K‐[Co(dien)(en)Cl]²⁺ was followed spectrophotometrically within the temperature range (40–60°C) in water, water–isopropyl alcohol, and water–tert‐butyl alcohol media of varying solvent composition up to 50 and 60 vol% of the organic solvent component respectively. The nonlinear plot of log k vs. D^?1_s was attributed to the differential solvation of the initial and transition states. The variation of ΔH^≠, ΔS^≠, and ΔG^≠ with the mole fraction of the organic component was analyzed and discussed. The isokinetic temperatures were found to be 330 and 317 K for water–isopropyl alcohol and water–tert‐butly alcohol mixtures respectively, indicating that the aquation reaction is entropy controlled. The application of free energy cycle at 25°C for the aquation reaction in both co‐solvents suggests that the transition state is more stable than the initial one. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 1–6, 2002     

THE PREPARATION OF TWO NOVEL HOMOALLYLIC ALCOHOLS VIA THE REACTION OF EPOXIDE WITH PHOSPHONIUM YLIDE

Abstract

Two novel homoallylic alcohols, E-4-(4-methoxyphenyl)- 1-phenyl-3-buten-1-01 and E-4-(3,4,5-trimethoxyphenyl)-1-phenyl-3-buten-1-01, were synthesised by the reaction of methelentriphenylphosphonium ylide with epoxide. The reaction first gave an initial betaine which upon treatment with butyl lithium gave a new ylide. When this new ylide reacted with the proper aldehyde, gave the corresponding homoallylic alcohol. Preliminary biological screening showed that the former alcohol possesses a significant estrogenic activity in rats. The latter alcohol was found to have partial antiestrogenic activity.     

Kinetics of reactions of ethylp-nitrophenyl ethylphosphonate with anionic nucleophiles in a detergentless microemulsion

The kinetics of reactions of ethylp-nitrophenyl ethylphosphonate with anionic nucleophiles in a detergentless water—oil microemulsion, formed in then-hexane—water—isopropyl alcohol system, was studied. The rate constants of the reactions in the microemulsion are higher than those in aqueous solutions and increase with increasing isopropyl alcohol: water ratio. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2262–2265, December, 1999.     

Acid‐mediated regioselective alkylation of 1,2,3‐triazole

1,2,3‐Triazole reacts with isopropyl alcohol in concentrated sulfuric acid to yield 1‐isopropyl‐1H‐1,2,3‐triazole as the only reaction product.     

Analyzing the surface properties of acrylic-based water-soluble polymers

The surface properties of newly synthesized N-methoxy isopropyl acrylamide, N-methoxy isopropyl methacrylamide, cyclo propyl acrylamide, and cyclo propyl methacrylamide polymers were investigated using inverse gas chromatography. The highest dispersive component of the surface energy value was obtained for cyclo propyl methacrylamide at 30°C. The values obtained for all polymers were decreasing with the increasing temperature. The values obtained for the acidic and the basic parameters revealed strong basic characters for the surface of N-methoxy isopropyl methacrylamide and cyclo propyl methacrylamide polymers and weak basic characters for the surface of N-methoxy isopropyl acrylamide and cyclo propyl acrylamide polymers.     

Alkaline bromine as volumetric reagent, analytical applications

Summary It has been shown that both isopropyl alcohol and acetone are quantitatively oxidised to acetic acid and carbon dioxide by alkaline hypobromite solutions and can be estimated volumetrically with the help of this reagent. It is already known that chromic acid oxidises isopropyl alcohol to acetone only under controlled conditions. A combination of the above two reagents can, therefore, be utilized for the volumetric estimation of isopropyl alcohol and acetone when present together in a mixture.The author's thanks are due to Dr. A. C. Chatterji, D. Sc., Head of the Department of Chemistry, Lucknow University, Lucknow, for the grant of laboratory facilities.     

Synthesis and antimicrobial activity of 6,6′‐arylidene‐bis‐[5‐hydroxy‐9‐methyl‐2,3‐diaryl thieno[3,2‐g‐]thiocoumarins]

A variety of novel 6,6′‐arylidene‐bis‐[5‐hydroxy‐9‐methyl‐2,3‐diaryl‐thieno[3,2‐g]thiocoumarins] 3a‐d , 4a‐d , 5a‐d , and 6a‐d were obtained by a reaction between 5‐hydroxy‐9‐methyl‐2,3‐diarylthieno[3,2‐g]thiocoumarins 1a‐d with aromatic aldehydes 2a‐d in isopropyl alcohol. The synthesized compounds were tested for their antimicrobial activity.     

(Vapor + liquid) equilibrium of the binary mixtures formed by acetonitrile with selected compounds at 95.5 kPa

Bubble point temperatures at 95.5 kPa, over the entire composition range, are measured for the binary mixtures of acetonitrile with acetyl acetone, anisole, bromobenzene, isopropyl alcohol, methyl tertiary butyl ether, and tetra ethoxy silane – making use of a Swietoslawski type ebulliometer. The measured liquid phase composition versus bubble point temperature are found to be well represented by the Wilson model. Measured values of the liquid phase mole fraction versus bubble point temperature data are presented, along with the computed values of the vapor phase mole fractions and activity coefficients, and discussed.     

Cornstarch/Poly(vinyl alcohol) Biocomposite Blend Films: Mechanical Properties,Thermal Behavior,Fire Retardancy,and Antibacterial Activity

In the present study, biocomposite films of starch/poly(vinyl alcohol) (St/PVA) reinforced with delignified Grewia optiva fiber and methyl methacrylate (MMA) grafted fibers were prepared using citric acid as a plasticizer and glutaraldehyde as the cross-linker. The biocomposite films were subjected to evaluation of mechanical properties, biodegradability, and antibacterial properties. The biocomposite films were characterized by using Fourier transform-infrared (FT-IR) spectrophotometry, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA/DTA/DTG). SEM showed good adhesion between St/PVA blend matrix and fibers. The antimicrobial activity of biocomposite films against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli was also explored. The results confirmed that the biocomposite films may be used for food packaging.     

Solution copolymerization of styrene and 2-hydroxyethyl mechacrylate.

The rate of solution copolymerization of styrene (M₁) and 2-hydroxyethyl methacrylate (M₂) was investigated by dilatometry. N,N-dimethyl formamide, toluene, isopropyl alcohol, and butyl alcohol were used as solvents. Polymerization was initiated by α,α′-azobisisobutyronitrile at 60°C. The initial copolymerization rate increased nonlinearly with increasing 2-hydroxyethyl methacrylate (HEMA)/styrene ratio. The copolymerization rate was promoted by solvents containing hydroxyl groups. Two different approaches were used for the prediction of copolymerization rates. The relationships proposed for the copolymerization rates calculation involve the effects of the total monomer concentration, mole fraction of HEMA, and of the solvent type. Different reactivity ratios were found in polar and nonpolar solvents: r₁ = 0.53, r₂ = 0.59 in N,N-dimethyl formamide, isopropyl alcohol and n-butyl alcohol; r₁ = 0.50, r₂ = 1.65 in toluene. The usability of these reactivity ratios was confirmed by batch experiments.