Dicyclopentadienoxidation. II 5. Katalysierte Flüssigphasenoxidation von Dicyclopentadien

Dicyclopentadiene Oxidation. II. Catalyzed Liquid-Phase Oxidation of Dicyclopentadiene The liquid-phase oxidation of dicyclopentadiene 1 by molecular oxygen was studied in the presence of MoO₂(acac)₂

1 Acac- Acetylacetonat

as a typical epoxidation catalyst. The yield of the mono-epoxides 2 and 3 is increased to 56,4% (uncatalyzed reaction: 43,6%). The ratio of the two mono-epoxides is decreased to 2/3 = 2,6 in relation to the uncatalyzed reaction ( 2/3 = 7,1). The influence of temperature, conversion and solvents is described. The bisepoxide 4 is formed at lower conversions than in the uncatalyzed reaction. But also at higher conversions of 1 not more than 10% of the bisepoxide 4 is formed     

The use of volume-averaging techniques to predict temperature transients due to water vapor sorption in hygroscopic porous polymer materials

Volume-averaging techniques developed for modeling drying processes in porous materials offer a convenient framework for analyzing vapor sorption in porous hygroscopic polymeric materials. Because of the large temperature changes associated with water vapor sorption in these materials (from 10° to 20°C), sorption/diffusion processes are best characterized through the coupled differential equations describing both the transport of energy and mass through the porous structure. Experimental and numerical results are compared for a variety of natural and man-made porous polymeric materials (textiles) using the volume-averaging technique. Boundary heat and mass transfer coefficients and assumptions about thermal radiative properties of the experimental apparatus are shown to influence results obtained with the numerical solution method. © 1997 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

J Appl Polym Sci 64: 493–505, 1997     

Dicyclopentadienoxidation. I,Unkatalysierte Flüssigphasenoxidation von Dicyclopentadien

Dicyclopentadiene Oxidation I. Uncatalyzed Liquid-Phase Oxidation of Dicyclopentadiene Dicyclopentadiene is oxidized by molecular oxygen to a mixture of the monoepoxides 2 and 3 . The identification of the epoxides 2 , 3 and 4 was executed with authentic samples prepared by epoxidation with peracetic acid or with tert-butylhydroperoxide in the presence of MoO₂(acac)₂

1 acac — Acetylacetonat

The main product is the substituted norbornene oxide 2 . Allylic oxidation is also observed. Remarkable amounts of hydroperoxides can be determined iodometrically. The formation of allylic oxidation products 7 , 8 , 9 and 10 was proved by GC-MS-analysis. It is shown that in the uncatalyzed liquid phase oxidation of dicyclopentadiene no more than 50% of epoxides are formed. The bisepoxide 4 was found in small amounts only at higher conversions of the dicyclopentadiene.     

Investigation of primers reducing the pink-ring formation in multilayer printed circuit boards

A rapid and easy screening test was applied to assess the capability of various formulated primers to reduce the defect of pink rings in multilayer printed circuit boards. The mixtures of silanes with multifunctional silanol groups (crosslinkers) and 3-glycidoxypropyl-trimethoxysilane

1 Systematic name: 3-(2,3-Epoxypropoxy)propyl-trimethoxysilane.

(referred to as silane C) or N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane

2 Systematic name: 3-[N-2-aminoethyl]aminopropyl-trimethoxysilane.

(silane B) were proved to be effective in reducing the pink rings. The performance of the mixed silanes using silane A and crosslinkers with aromatic groups were better than other formulated primers which was partly attributed to less amounts of hydrophilic groups and better integrity in the primer films. A developed primer consisting of siloxane compounds had the best performance. The online test confirmed the results from the screening test and demonstrated the feasibility of the designed screening test in assessing the performance of primers. The results of FTIR spectroscopy and thermogravimetric analyses confirmed that the effective primers coated on the copper oxides could improve the curing reaction and the thermal oxidative stability of the epoxy/CuO system.     

Fracture behavior of coated/uncoated graphite-epoxy composites

The static delamination behavior of graphite/epoxy composite specimens subjected to mode I tensile opening (using UDCB

1 Uniform double cantilever beam.

specimens), and pure mode II shear loading (using ENF

2 End-notched flexural.

specimens) were studied. The graphite epoxy composites for the study were made from commercially treated fibers, with and without an electropolymerized interlayer. The mode I fracture energy (G_IC) was found to be significantly higher (more than 50 percent) for the coated fibers. However, this improvement was accompanied by a high reduction (more than 3 times) in the mode II fracture energy (G_IIC). This effect is apparently related to poor adhesion between the interlayer and the epoxy resin, which may be corrected by use of a “top layer” of appropriate composition to form chemical bonds between the phases. The fracture toughness (K_IC) of composites made with commercially treated fibers was also evaluated, using double side-notched specimens.     

Glass fiber-reinforced epoxy composites

Glass fiber-reinforced epoxy composites were prepared from the matrix resins tetraglycidyl diaminodiphenylmethane

1 Systematic name: N,N,N′,N′-Tetrakis(2,3-epoxypropyl)-4,4′-diaminodiphenylmethane.

(TGDDM) and tetraglycidyl bis(o-toluidino)-methane

2 Systematic name: N,N,N′,N′-Tetrakis(2,3-epoxypropyl)-4,4′-bis(o-toluidino)methane.

(TGMBT) using various amines like 4,4′-diaminodiphenylmethane (DDM), 4,4′-diaminodiphenylsulfone (DDS) and diethylene triamine (DETA) as curing agents. The fabricated laminates were evaluated for their mechanical and dielectrical properties and chemical resistance. The composites prepared using an epoxy fortifier (20 phr) showed significant improvement in the mechanical properties.     

The STOBBE Condensation with Pyrrolyl Aldehydes – a synthesis of indole derivatives

The condensation of pyrrolyl-2-aldehyde or 1-methyl-pyrrolyl-2-aldehyde with dimethyl succinate, using sodium hydride as condensing agent, gave predominantly the halfesters 1a and 1c respectively. Their structure and (E)-configuration

1 i. e., pyrrol ring and COOCH₃ group are in trans position. This nomenclature follows the IUPAC 1968 Tentative Rules, Section E, Fundamental Stereochemistry, J. org. Chemistry 35 , 2849 (1970).

were confirmed by their cyclisation to the corresponding indole derivatives 2a–h .     

Photochemical and thermal stability of amaranth (FD&C red no. 2) in aqueous media

The decomposition of the formerly

1 This dye was delisted by the U. S. Food and Drug Administration in 1976, and has not been legally used in the U. S. in foods, drugs, or cosmetics since that date.

used food and pharmaceutical dye amaranth (FD&C Red No. 2) in water was studied under a variety of conditions. A matter of some concern is that one of the decomposition products is α-naphthylamine, a known carcinogen.     

Mowrah (Madhuca latifolia) seed saponin. Toxicological studies

Mowrah seed (Madhuca latifolia) meal

1 Meal refers to solvent extracted material.

contains high levels of saponin (7%) making it unsuitable for incorporation in animal feedstuff formulations. The saponin from mowrah seed meal was isolated and purified by paper chromatography. This was used for in vitro tests as well as pharmacological and acute toxicity studies for a better understanding of its properties and toxicity. The oral, intraperitoneal and intravenous LD₅₀ of mowrah saponins in mice are 1 g, 15–20 mg and 15 mg/kg body weight respectively. Processing of the meal to remove or inactivate the saponin will be essential prior to its incorporation in animal feeds.     

Jet-cooked starch-oil composite in polyurethane foams

A new jet-cooked starch—oil composite has been blended with a polyester polyol and then reacted with isocyanate to give a polyurethane foam. Infrared spectroscopy and microscopy have been used to examine the resultant products. Infrared spectra have shown the products contain the urethane structures and light and electron microscopy have shown the differences in the cell wall structures and networks of the foams when compared to the control foams. Inclusion of the starch—oil composite in the formulation resulted in increased viscosity of the reaction mixture as well as a more irregular cellular structure and a rougher texture of the cured foam. Larger cells were more abundant and there was more evidence of tearing during expansion. The scanning electron photomicrographs show the open-cell structure of both the control and blended foams and their reticular network, which is more uniform in the control. This examination provides insight into the foaming process and provides information to make the necessary adjustments for acquiring the desired polymeric product. Incorporation of the starch—oil composite in polyurethane foams provides a new dimension of possibilities for enhancing their physical, functional, and environmental properties. © 1997 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

J Appl Polym Sci 64: 1355–1361, 1997     

Functional polyamides. 3. Synthesis and chelating properties of a new poly(amide thioether)

Polymerization of β,β′-(ethylenedithio)dipropionitrile

1 IUPAC name: 4,7-dithiadecane dinitrile.

with formaldehyde in the presence of sulfuric acid was carried out in order to permit the synthesis of polymides containing thioether groups. The obtained poly(amide thioether)s were characterized; they coordinate mercury (II) with a high degree of selectivity.     

Gel permeation chromatography: Physical characterization and chromatographic properties of porasil

Porasil

1 Porasil is the Water Associates registered trademark for a powdered porous silica chromatographic substrate.

porous silica has been characterized by the methods of gas adsorption–desorption isotherms, mercury porosimetry, and electron microscopy. The pore structure has been shown to be quite heterogeneous, particularly at the surface of the particles. From the same sample of Porasil, columns were packed and calibrated in a gel permeation chromatograph. The availability of high molecular weight fractions of polystyrene allowed the exclusion limit of these materials to be determined for the first time. The heterogeneous pore structure did not seem to affect the effectiveness of these materials for macromolecular separation.     

Synthesis and characterization of melt-polymerizable aminophthalocyanine monomers

The strategy, synthesis, and characterization of a soluble amine-functionalized phthalocyanine monomer and two examples of its polymerization into optically transparent glasses are reported. A simple, fast, and versatile method for incorporating metal ions into the metal-free phthalocyanine is demonstrated. Measurements of the nonlinear optical properties associated with a lead-substituted phthalocyanine/urethane copolymer are also reported. © 1995 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Effects of water content on the properties of starch/poly(ethylene–vinyl alcohol) blends

The physical properties of unmodified starch, poly(ethylene vinyl alcohol), glycerol, and water mixtures are reported. Thermal and melt-flow properties of the preprocessed, physically mixed materials were determined along with the tensile properties and morphology of injection-molded microtensile samples. Melt-flow properties were measured by a capillary rheometer, and the water content was varied from 4 to 18%. The morphology, rheology, and tensile properties are all highly related to the percentage of water present. A transition in the tensile properties and morphology of the blends was observed at approximately 11% moisture content. © 1994 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Synthesis of phosphorus-containing wofatit cation exchangers and their affinity toward selected cations

A number of solid Cationits have been prepared derived from Wofatit

1 Trademark, VEB Chemiekombinat Bitterfield.

gel and canal structures: styrene/DVB, chloromethylated ST/DVB, and acrylic acid/DVB copolymers. To functionalize the copolymers, PCl₃/AlCl₃ and dialkyl phosphites or trialkyl phosphites were used. The influence of the polymer matrix structure and the chemical structure of the functional groups of obtained Ionits on their affinity toward 23 metallic cations in acidic media has been investigated using the conductivity method. To obtain comparison data, commercial “Wofatit”–sulfonic and–carboxylic Cationits, have been tested under identical conditions.     

Alumina trihydrate as a flame retardant filler for flexible vinyl compounds

In those flexible vinyl compounds which can accept fillers, alumina trihydrate can significantly improve flame resistance as measured by oxygen index

1 It should be appreciated that degrees of flammability as measured by small-scale tests such as oxygen index may in no way reflect the relative hazard of these same materials when involved in a fully developed fire.

. Over a range of plasticizer concentrations, the lower the concentration of burnable plasticizer, the greater the contribution of hydrate to flame retardancy. Combinations of alumina trihydrate with antimony oxide are especially effective for improving the flame resistance of flexible vinyl compounds.     

Porous bead aliphatic-aromatic methacrylate copolymers,I. Effect of polymerization conditions on porous structure formation of methyl methacrylate — di(methacryloyloxymethyl)naphthalene copolymers

The influence of inert porogenic mixture and monomer mixture composition and concentration on specific surface areas, pore size distribution, volumes of pores capable of capillary condensation of nitrogen and true density of copolymers were investigated for a new type of methacrylate monomer system: methyl methacrylate and di(methacryloyloxymethyl)naphthalene. The obtained copolymers exhibit similar character as it is typical for PPS

1 PPS = Porous by Precipitant and Solvent.

styrene-divinylbenzene resins.     

Synthesis of phosphorus-containing polymers with potential bioactivity

Phosphorylation of poly(N-vinyl pyrrolidone-co-vinyl amine) and poly(N-vinyl pyrrolidone-co-glycidylcrotonate

1 Systematic name: (2,3-Epoxypropyl)crotonate.

) is realized by Atherton-Todd and Fields-Kabachnik reactions and by the means of direct interaction with phosphorus trichloride and phosphorus trichloride oxide. The composition and structure of the isolated final products was proved by NMR (¹H and ³¹P), IR spectroscopy and elemental analysis.     

Über die katalysierte Flüssigphasenoxidation von cis- und trans-Oct-4-en

The Catalyzed Liquid-Phase Oxidation of cis- and trans-Oct-4-ene The influences of MoO₂(acac)₂

1 acac-Acetylacetonat.

, MoO ₃ and Co(acac) ₃ on the liquid-phase oxidation of cis- and trans-oct-4-ene at 110°C were studied. In the presence of molybdenum catalysts the yield of epoxides and the stereoselectivity of epoxide formation are increased. The results are in good agreement with the hypothesis that molybdenum compounds effect only the stereospecific reaction of the hydroperoxides formed with the starting olefin yielding the corresponding epoxide. The cobaltic complex increases the rate of autoxidation, but has no remarkable influence on the yield of epoxides. In the presence of Co(acac)₃ more trans-epoxide is formed from cis-oct-4-ene than in the uncatalyzed reaction. This can be explained by an increase of the lifetime of the intermediate peroxyalkyl radical, effected by complex formation of the radical with a cobalt species.     

Effects of jet-cooking conditions upon intrinsic viscosity and flow properties of starches

This work examined the sensitivity of intrinsic viscosity values of jet-cooked waxy maize starch to initial pH conditions and the effects of jet-cooker steam pressure parameters upon the intrinsic viscosity and flow viscosity values of four jet-cooked starches. Flow viscosities of the 10 wt % cooked starches and intrinsic viscosities in 90% DMSO-H₂O were the lowest when mixing and turbulence during steam jet-cooking was increased (i.e., by adjusting steam line pressure vs. pressure within the cooking chamber to allow greater amounts of steam to flow through the apparatus). The percent decreases of the intrinsic viscosity caused by the most severe cooking conditions compared to gentle cooking conditions were 52, 45, 32, and 12, respectively, for waxy maize, waxy rice, normal maize, and 70% high amylose maize starches. Initial pH values, from 3 to 10.5, of waxy maize starch had minor effects upon the intrinsic viscosity of the jet-cooked material. © 1996 John Wiley & Sons, Inc.

1 This is a U.S. Government work and, as such, is in the public domain in the United States of America.