Synthesis of monocarboxylic polyoxyethylenes

Summary The various methods of synthesis which can be used to prepare -carboxy polyoxyethylenes are reviewed. The synthesis and the purification of -methoxy -carboxy polyoxyethylenes ( ) are reported. The process consists of the reaction of halogenoacetic acids with an -methoxy -sodium hydroxylate polyoxyethylene followed by a purification by extraction. ,-dimethoxy and -methoxy -ethyl carboxylate polyoxyethylenes were synthesized.     

Preparation of macrocyclic polystyrene

Summary A method for the preparation of cyclic polystyrene is described. Bifunctionally growing living polystyrene is terminated by addition of equimolar amounts of , -dichloro-p-xylene under conditions of high dilution.Prof. Dr. Dr. h. c. mult. Hermann Mark dedicated on the occasion of his 85th birthday     

Properties ofSrMO 3-δ(M=Fe,Co) as oxygen electrodes in alkaline solution

Strontium ferrates and cobaltates with compositions SrFeO_3- (0.060.40) and SrCoO_3- (0.040.30) were synthesized. The dependence of the oxygen electrode properties on the value was examined in 1 mol dm^–3 KOH solution. In the SrFeO_3- series, the samples with 0.24<<0.29, showed the highest activity in both oxygen evolution and reduction reactions. In contrast, no strong dependence on the value was observed in SrCoO_3-, which also showed a high catalytic activity for oxygen evolution.     

Ruthenium catalyzed regioselective step-growth copolymerization of 4′-methoxyacetophenone,or 4′-phenoxyacetophenone and α, ω-dienes

Summary Ruthenium catalyzed step growth copolymerization of 4-methoxyacetophenone or 4-phenoxyacetophenone and ,-dienes such as 1,3-divinyltetramethyldisiloxane or 3,3,6,6-tetramethyl-3,6-disila-1,7-octadiene give copolymers which have respectable molecular weights. The synthesis and characterization of these copolymers is reported. Higher molecular weight copolymers are quite thermally stable.     

Examples of new synthetic routes to pendant ester-ether derivatives of α-hydroxymethylacrylate polymers

Summary Three routes to new ester-ether derivatives of ethyl -hydroxymethylacrylate (EHMA) and t-butyl -hydroxymethylacrylate (TBHMA) were investigated. The first approach involved the preparation of chloroacetate derivatives of EHMA and TBHMA as intermediates followed by attempted etherification of the chloroacetate group. All attempted nucleophilic reactions of ethyl -chloroacetoxymethacrylate (ECAM) and t-butyl -chloroacetoxymethacrylate (TBCAM) gave Michael-type substitution products with loss of the -chloroacetyl substituent. Polymer substitution was therefore investigated. Bulk polymerization of ECAM with AIBN gave unexpectedly high molecular weight polymer with a number average value of 1.15 million. This homopolymer was substituted with 4-phenylphenol in excellent conversion. The second approach involved the reaction of ethyl -chloromethylacrylate (ECMA) with -ethers of acetic acid sodium salts using phase transfer catalysis. The methoxyacetate derivative was prepared and polymerized to give a polymer with a number average molecular weight of 260,000. The third route to ester-ether derivatives involved three steps: reaction of t-butylchloroacetate with an alcohol to give the ether, conversion of the t-butyl group to the acid chloride, and reaction of the acid chloride with EHMA or TBHMA. The 2-(4-phenylphenoxy)acetate derivative of EHMA was prepared using this method, and converted to high polymer.     

Chemical effects in commercial and laboratory mixtures of ‘reactive’ phosphate rock and acidulated fertilisers

The chemical analyses of different size fractions of a variety of commerical and laboratory prepared samples of partially acidulated phophate rocks and mixtures of reactive phosphate rock and single superphosphate (called LONGLIFE in New Zealand) have been studied. Whereas only minor chemical segregation effects have been observed for partially acidulated products quite a large bias has been established for LONGLIFE materials, and more especially commercial samples, where larger proportions of phosphate rock were found in the lower size fractions. This inhomogeneity was considered to arise from poor mixing of components and subsequent inconsistent granulation; more stringent rejection criteria for undersize material would greatly assist in improving the product quality. Chemical deactivation of the phosphate rock residue in LONGLIFE materials was also observed; this can be partially explained by a selective reaction of the reactive phosphate rock component with acid still present at the time of mixing with the single superphosphate component.     

Cooperative inclusion of sodium 1-pyrenesulfonate by γ-cyclodextrin

Summary The interaction of -cyclodextrin(-CD) with sodium 1-pyrenesulfonate(PS) was studied spectrophotometrically. -CD was found to cause much larger decrease in the absorption maxima of PS than -CD. The fluorescence spectra of PS in the presence of -CD showed excimer emission, while those of PS with -CD showed only monomer emission, indicating that -CD forms 12 (-CDPS) complexes in which two PS molecules are included in the -CD cavity in a face-to-face fashion. The binding isotherm showed a sigmoidal curve. The association constants were estimated by computer simulation of the binding curve. The 12 (CDPS) complex was found to be much more stable (K=10⁶ M^–1) than the 11 complex (K=1 M^–1). At high concentration of -CD another -CD cooperates in binding two PS molecules, resulting in the formation of a 22 complex.     

Catalytic oxidation of methanol to methyl formate over silver – a new purpose of a traditional catalysis system

Catalytic reaction was performed in the unregarded temperature region over silver catalysts with long catalytic lifetime for the conversion of methanol to methyl formate. O-saturated or O-saturated silver catalysts were studied individually to identify the roles of O, O in the oxidative esterification of methanol over an unsupported polycrystalline silver catalyst. A synergic process is proposed based on the coexistence of -oxygen species and -oxygen species on the surface of polycrystalline silver at about 573 K.     

Ruthenium catalyzed regioselective copolymerization of anthrone,fluorenone, or xanthone with α,ω-dienes

Summary This paper reports a novel ruthenium catalyzed regioselective copolymerization reaction between anthrone, fluorenone or xanthone and ,-dienes such as 1,3-divinyltetramethyldisiloxane and 3,3,6,6-tetramethyl-3,6-disila-1,7-octadiene. This reaction involves the ruthenium catalyzed regioselective Anti-Markovnikov insertion of the carbon-carbon double bonds of the ,-dienes into the aromatic carbon-hydrogen bonds which are ortho to the carbonyl group of anthrone, fluorenone or xanthone. Similar ruthenium catalyzed copolymerization reactions between acetophenone and ,-dienes [1] have been recently reported as have reactions between acetophenone and alkenes to yield monomeric ortho-alkyl substituted acetophenones [2].     

Synthesis of new metal-containing side-chain monomers and polymers

New metal-containing vinyl monomers, hexyl-6-oxy-{4-[4-(4-carboxy cyclopentadienyl manganese tricarbonyl phenyl)phenyl]benzoyloxy}methacrylate and hexyl-6-oxy-{4-[4-(4-ferrocenoyl phenyl)phenyl]benzoyloxy}methacrylate, and the corresponding homopolymers and random copolymers with hydroxy monomer hexyl-6-oxy-{4-[4-(4-hydroxyphenyl)phenyl]benzoyloxy}methacrylate were synthesized. The compounds were characterized by¹H NMR; their thermal behavior was investigated by means of differential scanning calorimetry. Monomers and polymers containing the ferrocene unit melt at lower temperatures than those derived from the cyclopentadienyl managanese tricarbonyl moiety. The melting temperatures of the monomers and polymers ranged from 399 to about 515 K, Both monomers and polymers failed to exhibit mesogenic behavior. Values ofM _n,M _w,M _w/M _n, and degree of polymerization were obtained by gel permeation chromatography. TheM _n ranged from 16,500 for the copolymer containing hexyl-6-oxy-{4-[4-(4-ferrocenoyl phenyl)phenyl] benzoyloxy}methacrylate and hydroxy monomer hexyl-6-oxy-{4-[4-(4-hydroxyphenyl)phenyl]benzoyloxy}methacrylate at a 1:3 ratio to 26,000 for the copolymer containing hexyl-6-oxy-{4-[4-(4-carboxy cyclopentadienyl manganese tricarbonyl phenyl)phenyl]benzoyloxy}methacrylate and hydroxy monomer hexyl-6-oxy-{4-[4-(4-hydroxyphenyl)phenyl]benzoyloxy}methacrylate at a 1:3 ratio.M _w/M _n ranged from 1.6 in the case of the copolymer containing hexyl-6-oxy-{4-[4-(4-carboxy cyclopentadienyl manganese tricarbonyl phenyl)phenyl]benzoyloxy}methacrylate and hydroxy monomer hexyl-6-oxy-{4-[4-(4-hydroxyphenyl)phenyl]benzoyloxy}methacrylate at a 1:3 ratio to 2.2 in the case of poly(hexyl-6-oxy{4-[4-(4-carboxy cyclopentadienyl manganese tricarbonyl phenyl)phenyl]benzoyloxy}methacrylate).     

Effects of crystallinity and supermolecular formations on the interfacial shear strength and adhesion in GF/PP composites

Aim of this study was to screen the morphological effects on the interfacial shear strength (i) in glass fibre (GF) reinforced isotactic polypropylene (iPP) model composites. i was determined by a modified single fibre pull-out technique. It was established that the relation between i (5–6 MPa) and the yield stress of the iPP (y30 MPa) is at about 1:6 and that the i values were not influenced by the mophological superstructure set under isothermal crystallization conditions. Increased i was only observed when specimens were produced non-isothermally, by quenching (i9 MPa). This improvement could not be related to thermal shrinkage stresses. The enhancement in i was attributed to better wetting and improved adhesion due to the enlarged amorphous PP (aPP)-phase. A schematic adhesion model considering the wetting behaviour of aPP and iPP was proposed.     

An investigation of the interaction of potassium ions with poly(dimethylsiloxane)

The interactions of potassium ions with , -hydroxy-terminated and , -trimethylsilyl-terminated poly(dimethylsiloxanes) (PDMS) have been investigated. After mixing with potassium hydroxide followed by partial extraction, the , -hydroxy-terminated PDMS samples gave elastomeric materials which are thought to result from aggregation of terminal potassium silanolate ion pairs. Uniaxial tensile testing of these materials was carried out at 298 K. The , -trimethylsilyl-terminated PDMS, when mixed with potassium hydroxide, however, gave completely soluble material following identical solvent extraction procedures.     

Characterization of some organic poly(aminiumphosphate)s

Summary Metachromatic reactions of MB and AO are studied with poly(aminium phosphate)s. The main band() at 665 m and 492 m for MB and AO are shifted to 580 m and 455 m respectively (-bands). The metachromatic values at different concentrations of poly(aminium phosphate)s are also reported. The dye association for MB with these polymer derivatives is investigated conductometrically as well. It is observed that MB can be at the most bind with the phosphate residue of polymer upto 11 molar ratio. The polymeric nature was further established by paper chromatographic technique in Terry's, Ebel's & Pfrengle's solvents.     

Sex pheromone components of corn stalk borerSesamia nonagriodes (Lef.) isolation,identification, and field tests

Z-11-Hexadecenyl acetate (Z11–16OAc), dodecyl acetate (12OAc),Z-11-hexadecenal (Z11–16Aid), andZ-11-hexadecenol (Z11– 16OH), were found in pheromone gland extracts of femaleSesamia nonagriodes (Lef.) [Lepidoptera: Noctuidae]. These four components were also present in airborne volatiles collected from calling virgin females in a 651889 ratio. Hexadecyl acetate (16OAc) was also detected but found to be inactive. The identification was based on multicolumn GC analysis, mass spectrometry, and field activity.Z11–16OAc is the major sex pheromone component; the addition of the secondary components individually decreased male captures. The blend of the four synthetic components in 691588 ratio was highly attractive to males; 200 g per trap was the most effective concentration in field tests.Lepidoptera: Noctuidae     

Theoretical aspects of bonding in silicon compounds

Ab initio-calculated bond dissociation energies of Si=Si and C=C are discussed by means of atomic ionization energies and p-p() AO overlap. At the same time ring strain energies of C- as well as Si-rings are estimated by homodesmic reactions where, according to Baeyer, the two-membered rings C=C and Si=Si are chosen to be the first members of the respective series. Thus, a better understanding of the double bonds can be gained. In addition, the exceptional structural and spectroscopic behavior of the five-membered Si-ring is discussed. Finally, the strikingly different results obtained in computational studies of the initial step for polymerization of the systems O=C=O and O=Si=O are discussed.     

Effect of the type of mullite and certain additives on the sintering process of mullite-zircon specimens

Conclusions The effect of the type of mullite on the sintering process of mullite-zircon specimens was studied. It was shown that using electromelted mullite as chamotte ensures optimum properties. Sintered mullite increases the porosity of the products.The optimum content of the argillaceous binder for obtaining dense and strong specimens was found to be 10%.It was shown that highly refractory oxides intensify (activate) the sintering process of the mullite-zircon products obtained using electromelted mullite and strengthen them to the maximum extent. In this case, their thermal shock resistance remains quite high.The salts of REE have a positive effect on the sintering process of the mullite-zircon specimens at 1650°C and improve their strength; however, in this case, their thermal shock resistance decreases abruptly. The oxides of REE lead to less intense sintering of the mullite-zircon specimens but these additives increase their strength significantly and impart the required thermal shock resistance.The sintering process of the mullite-zircon specimens occurs in the presence of a liquid phase and is accomplished in three stages whose kinetics can be described by the relationships (proportionalities)l/l^1,3, l/l^1/2, and l/l^1/3, respectively.Translated from Ogneupory, No. 8, pp. 12–17, August, 1988.     

Enhancement of βα-recrystallization in β-form isotactic polypropylene during heating after roll deformation

Summary -form isotactic polypropylene shows -recrystallization behavior (recrystallization from - to -form) during slow heating. This is enhanced by deformation. -form specimen with uniaxially oriented lamellae was deformed by rolling, and -recrystallization was studied by DSC and x-ray diffraction. The result showed that (1) — recrystallization is promoted with the degree of deformation. (2) Deformed specimen shows -recrystallization from considerably low temperature compared with the undeformed one. (3) The recrystallized -form is c-axis-oriented along the roll direction. From these results the -recrystallization mechanism was discussed in view of -nucleus formation by deformation.     

Ethynylene-disilanylene copolymers

Polymers of structure (SiR₂SiR₂-C C-SiR₂SiR₂-C C) _n , in which ethynylene units alternate with disilylene units, have been prepared by two routes: (a) condensation of dichlorodisilanes with dilithium derivatives of 1,2-diethynyldisilanes and (b) ring-opening polymerization of strained cyclic disilanylene-acetylnes, (SiR₂SiR₂C C)₂. The polymers display UV absorption near 240 nm indicative of – conjugation between the Si₂ and the C C moieties. Polymers with R=R=n-Bu or R=n-Bu, R=Ph, undergo solid-state transitions to form liquid crystalline mesophases resembling those observed for many poly(silylenes). Single crystals were obtained for the polymer with R=R=CH₃, by precipitation from dilute cyclohexane solution. The solid-state properties and structures of this family of polymers are discussed.This paper was presented at the Second International Topical Workshop, Advances in Silicon-Based Polymer Science.     

Electrochemical and thermal behaviour of LiNi0.8Co0.2O2 cathode in sealed 18650 Li-ion cells

The electrochemical performance of LiNi_0.8Co_0.2O₂ cathodes in Li ion cells was investigated under static and dynamic load conditions, which prevail in electric and hybrid vehicles using constant current constant voltage and hybrid pulse power characteristic procedures.The thermal properties of this cathode were investigated using the differential scanning calorimetric and accelerated rate calorimetric techniques. The cell fabricated with a LiNi_0.8Co_0.2O₂ cathode showed excellent power performance. The specific energy produced by the 18650 cell was 90 Wh kg^–1 at 100 W kg^–1 power level.     

Sex pheromone chemistry of the western spruce budwormChoristoneura occidentalis Free

SCOT capillary Chromatographic and SCOT capillary chromatographic-mass spectrometic analyses of gland washes and effluvia of virgin femaleChoristoneura occidentalis Free, have been conducted with both a diapausing and nondiapausing strain of this insect. The following compounds were identified in gland washes and effluvia in both strains:E andZ11–14Ald,E andZ11–14Ac,E andZ11–14OH and 14Ald, 14Ac, and 14OH. The average aldehyde: acetate: alcohol ratio found by analysis of single glands by virgin females (nondiapausing strain) was 170.73. Analysis of virgin female effluvia gave this ratio as 1038 (diapausing strain: %Z=8, 11, 15, respectively) and 1036 (nondiapausing strain: %Z=8, 11, 12, respectively). The saturated components were generally 1–2% of theE isomer in each case. Comparisons of EAG responses of bothC. occidentalis andC. fumiferana toE11–14Ald,E11–14Ac andE11–14OH were made. Correlations with both laboratory and field data previously published were also made betweenC. fumiferana andC. occidentalis.Lepidoptera: Tortricidae.