The Chemistry of Vulcanization. IX. Accelerating Mechanism of 2-Aminothiobenzothiazole

1962 ◽  
Vol 35 (2) ◽  
pp. 484-490
Author(s):  
Haruko Fukuda ◽  
Jitsuo Tsurugi
Keyword(s):  
Zinc Salt ◽  
Minor Amount ◽  
Reaction Products ◽  
Reaction Sequence ◽  
Minor Degree ◽  
A Minor ◽  
Sulfur Radical ◽  
Homolytic Dissociation ◽  
Free Sulfur

Abstract 2-Aminobenzothiazole, i.e., 2-aminobenzothiazolylaulfenamide, MSNH2 was used as a model of the commercial sulfenamide type accelerators. Behavior of MSNH2 was studied in diphenylmethane, DPM, which served as a hydrocarbon containing α-methylenic hydrogen. MSNH2 decomposes in DPM at 140–160° to give MS· and ·NH2 together with a minor amount of free sulfur radical. This suggests homolytic dissociation of the S—N bond as well as the C—S bond of MSNH2, though the latter bond dissociates in minor degree. Dissociation of both bonds makes the reaction sequence complicated. When sulfur was added to the MSNH— DPM system, the radical MS· (or M·) opens the sulfur ring to accelerate the reaction of DPM with sulfur. The presence of sulfur results in the less complicated reaction products. The activating mechanism of zinc butyrate in the reaction involving MSNH2, sulfur and DPM is the same as that involving thiazole type accelerators. However, the zinc salt of MBT which is produced from MSNH2 and zinc butyrate interacts with the radical ·NH2, giving an intermediate 2-amino-benzothiazole, MNH2. The latter reacts with zinc butyrate to give N-(2-benzo-thiazolyl) butyramide, RCONHM. Evolution of ammonia was observed even in the presence of sulfur and zinc butyrate.

Phase stability of B2O3-added Ba2Ti9O20 ceramic: Processing effects

2003 ◽  
Vol 18 (1) ◽  
pp. 201-207 ◽  
Author(s):  
Sea-Fue Wang ◽  
Chuang-Chung Chiang ◽  
Chai-Hui Wang ◽  
Jinn P. Chu
Keyword(s):  
Phase Transformation ◽  
Phase Stability ◽  
Sintering Temperature ◽  
Host Material ◽  
Minor Amount ◽  
Reaction Products ◽  
Effective Role ◽  
Processing Effects ◽  
A Minor

Preparation of dense and phase-pure Ba2Ti9O20 is generally difficult to achieve using solid-state reaction, since there are several thermodynamically stable compounds in the vicinity of the desired composition. This study investigated the effects of B2O3 on the densification, microstructural evolution, and phase stability of Ba2Ti9O20. Samples from the host material (2BaO · 9TiO2) with and without the addition of 5 wt% B2O3 were prepared through different processing routes. For the pure host material sintered at temperatures ranging from 800 to 1100 °C, the reaction products followed the sequence of BaTi2O5 → BaTi4O9 → BaTi5O11 → Ba2Ti9O20. The phase transformation proceeded faster in the bulk compared to the free surface of the sample. BaTi5O11 and BaTi4O9 with a minor amount of Ba2Ti9O20 were found in the ground powder of ceramics sintered at 1100 °C. For the samples prepared from host material with the addition of 5 wt% B2O3, Ba2Ti9O20 started to form at temperatures as low as 800 °C. The sequence of reaction products followed Ba4Ti13O30 → BaTi4O9 → BaTi5O11 → Ba2Ti9O20. Sintering at above 1000 °C yielded pure Ba2Ti9O20 phase, suggesting the effective role of B2O3 on the phase stability of Ba2Ti9O20. It was found that precalcination of host material before the addition of B2O3 gives an additional benefit to the Ba2Ti9O20 formation. Crystallization of pure Ba2Ti9O20 phase was completed at a sintering temperature as low as 900 °C without any solid solution additive such as SnO2 or ZrO2, due to the fact that the phase transformation of the samples began with BaTi4O9 and BaTi5O11 during sintering. Also, B2O3 was found to be unstable during the high-temperature sintering at 1200 °C, and the results are discussed.

Platelet Incorporation of Labelled Adenosine and Adenosine Diphosphate

1969 ◽  
Vol 22 (02) ◽  
pp. 304-315 ◽  
Author(s):  
E. W Salzman ◽  
T. P Ashford ◽  
D. A Chambers ◽  
Lena L. Neri
Keyword(s):  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Platelet Inhibition ◽  
Electron Microscopic ◽  
Platelet Binding ◽  
Minor Degree ◽  
A Minor ◽  
Plasma Marker ◽  
Electron Microscopic Radioautography ◽  
Simultaneous Assessment

SummaryAfter incubation of platelet-rich plasma with labelled adenosine or ADP, platelet incorporation of radioactivity was assessed. Platelets were rapidly separated for counting by filtration through cellulose acetate Millipore. Inulin-H3 served as a plasma marker, and triple isotope techniques permitted simultaneous assessment of the behavior of the adenine and phosphate moieties of ADP without washing of platelets. In other experiments, electron microscopic radioautography was employed to trace the label after platelet incorporation.The results were consistent with previous reports that ADP is dephosphorylated in plasma and is incorporated by platelets only as a dephosphorylated residue, probably adenosine. The label crossed the platelet membrane and entered the platelet, where it was distributed in platelet granules and the agranular cell sap. Concentration within granules occurred to a minor degree.The results support the hypothesis that platelet aggregation by ADP occurs without a persistent bond of ADP to the platelet. Inhibition of aggregation by adenosine probably depends on a metabolic or transport process rather than on competition between adenosine and ADP for platelet binding sites.

scholarly journals Odour-active compounds in liquid malt extracts for the baking industry

2021 ◽  
Author(s):  
Nadine S. Rögner ◽  
Veronika Mall ◽  
Martin Steinhaus
Keyword(s):  
Threshold Value ◽  
Starting Material ◽  
Minor Amount ◽  
Malt Extract ◽  
Important Process ◽  
Gas Chromatography Olfactometry ◽  
Odour Threshold ◽  
A Minor ◽  
Baking Industry ◽  
Insight Into

AbstractAn odorant screening by gas chromatography–olfactometry (GC–O) and a crude aroma extract dilution analysis (AEDA) applied to the volatiles isolated from a light and a dark liquid malt extract (LME) by solvent extraction and solvent-assisted flavour evaporation (SAFE) identified 28 odorants. Fifteen major odorants were subsequently quantitated and odour activity values (OAVs) were calculated as ratio of the concentration to the respective odour threshold value (OTV). Important odorants in the light LME included 3-(methylsulfanyl)propanal (OAV 1500), (E)-β-damascenone (OAV 430), and 4-ethenyl-2-methoxyphenol (OAV 91). In the dark LME, sotolon (OAV 780), 3-(methylsulfanyl)propanal (OAV 550), (E)-β-damascenone (OAV 410), acetic acid (OAV 160), and maltol (OAV 120) were of particular importance. To get an insight into the changes during malt extract production, the quantitations were extended to the malt used as the starting material for both LMEs. Addition of a minor amount of water to malt before volatile extraction was shown to be effective to cover the free as well as the bound malt odorants. Results showed that some LME odorants originated from the starting material whereas others were formed during processing. Important process-induced LME odorants included (E)-β-damascenone and 4-ethenyl-2-methoxyphenol in the light LME as well as maltol, sotolon, (E)-β-damascenone, and 2-methoxyphenol in the dark LME. In summary, the odorant formation during LME production was shown to be more important than the transfer of odorants from the malt.

CLAY-INORGANIC STUDIES. II. HYDROXY ALUMINUM PHOSPHATE–MONTMORILLONITE COMPLEX

1975 ◽  
Vol 55 (2) ◽  
pp. 225-233 ◽  
Author(s):  
H. KODAMA ◽  
M. D. WEBBER
Keyword(s):  
Relative Humidity ◽  
Room Temperature ◽  
Aluminum Phosphate ◽  
Silicate Layer ◽  
Basal Spacing ◽  
Minor Amount ◽  
Chemical Compositions ◽  
A Minor ◽  
Positively Charged ◽  
Water Contents

Two specimens of hydroxy aluminum phosphate interlayer materials in montmorillonite clay were prepared with 7.20 meq Al and 11.29 meq H3PO4/g clay and with 14.40 meq Al and 22.58 meq H3PO4/g clay, and the resulting complexes studied by chemical and mineralogical methods. Both interlayer materials were slightly positively charged and except for different water contents their chemical compositions were almost identical. They contained Al, PO4 and H2O and a minor amount of Ca and approximated hydrous AlPO4∙nH2O. The mole ratios of Al:Ca:PO4:OH were 1.00:0.08:0.92:0.24 and 1.00:0.05:0.91:0.24, respectively. The interlayer materials appeared to be loosely packed and distributed sparsely in interspaces of the montmorillonite. The degree of packing was greater for the preparation with the larger amount of interlayer material. The materials increased the montmorillonite basal spacing to 23.3 Å under air-dry condition (30–40% relative humidity) but did not affect the lateral dimensions. The basal spacing varied somewhat with relative humidity at room temperature and decreased markedly as water was driven off by heating. Heat treatments between room temperature and 300 C sharply reduced the d001 spacings to 16.7 Å which persisted up to 700 C. It is postulated that the large basal spacings occur because the hydrated interlayer materials have a framework structure with tunnels along the c-axis. This being so, changes in the spacings with different humidities might result from the movement of water molecules among interstitial spaces existing around and between the loosely distributed molecules of interlayer material. The 16.7 Å spacing for the dehydrated phase corresponds to the sum of 7.0 Å, the edge dimension of an orthorhombic anhydrous AlPO4 and 9.7 Å, the silicate layer thickness.

Isolation of radioactive iodothyronines for kinetic studies: a comparison of two methods

1982 ◽  
Vol 99 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Jens Faber ◽  
lb Bo Lumholtz ◽  
Carsten Kirkegaard ◽  
Kaj Siersbæk-Nielsen ◽  
Thorkild Friis
Keyword(s):  
Radioactive Iodine ◽  
Single Injection ◽  
Kinetic Studies ◽  
Acid Precipitation ◽  
Relative Difference ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Minor Degree ◽  
A Minor

Abstract. A method based on the principle of gel separation followed by antibody extraction (GSAE) has been developed for isolation of radioactive thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3), 3,3'-diiodothyronine (3,3'-T2), 3',5'-diiodothyronine (3',5'-T2) and 3'-monoiodothyronine (3'-T1) in serum. This method was used for the estimation of the metabolic clearance rate (MCR) of the iodothyronines using the single injection, non-compartmental approach, and was compared to the conventional trichloroacetic acid precipitation/ethanol extraction (TCA-E) technique. The GSAE method excluded the co-determination of radioactive iodine and iodoproteins, whereas the co-determination of radiolabelled daughter iodothyronines was found negligible. The relative difference of duplicate estimations of MCR was approximately 10%. Using the TCA-E method for isolation of tracer, the MCR of T4, T3 and rT3 was underestimated to a minor degree (20%), whereas the MCRs of 3,3'-T2, 3',5'-T2 and 3'-T1 were 20–40% of those estimated by the GSAE method. In conclusion the GSAE method was found suitable for kinetic studies of iodothyronines, whereas the TCA-E method cannot be used for turnover studies of 3,3'-T2, 3',5'-T2 or 3'-T1.

scholarly journals Vinyl ether hydrolysis. XIV. 2-Methoxy-2,3-dihydropyran: concurrent reaction of vinyl ether and acetal functional groups

1980 ◽  
Vol 58 (21) ◽  
pp. 2199-2202 ◽  
Author(s):  
R. A. Burt ◽  
Y. Chiang ◽  
A. J. Kresge
Keyword(s):  
Vinyl Ether ◽  
Isotope Effect ◽  
Reaction Rate ◽  
Functional Group ◽  
Minor Amount ◽  
Cyanoacetic Acid ◽  
Buffer Solutions ◽  
Hydrogen Isotope Effect ◽  
A Minor ◽  
Hydrolysis Of

The hydrolysis of 2-methoxy-2,3-dihydropyran shows a normal isotope effect (kH/kD > 1) under catalysis by the hydrogen ion and gives an accurately linear dependence of reaction rate upon undissociated acid concentration in cyanoacetic acid and formic acid buffer solutions. This substrate, therefore, unlike its higher homolog, 9-methoxyoxacyclonon-2-ene, provides no evidence in support of an anything but a normal mechanism for vinyl ether hydrolysis. Analysis of the hydrogen isotope effect suggests that a minor amount (8%) of this hydrolysis occurs via reaction of the acetal functional group.

scholarly journals Silica-Based Composites with Enhanced Rheological Properties Thanks to a Nanosized Graphite Functionalized with Serinol Pyrrole

2021 ◽  
Vol 11 (23) ◽  
pp. 11410
Author(s):  
Gea Prioglio ◽  
Silvia Agnelli ◽  
Stefano Pandini ◽  
Maurizio Galimberti
Keyword(s):  
Rheological Properties ◽  
High Surface ◽  
High Surface Area ◽  
Minor Amount ◽  
Carbon Filler ◽  
Hybrid Filler ◽  
Carbon Efficiency ◽  
Dynamic Rigidity ◽  
A Minor ◽  
New Generation

Silica-based rubber composites have tremendous importance, as they allow the reduction in hysteresis in demanding dynamic-mechanical applications such as tire compounds and hence have a lower environmental impact. However, they also present drawbacks such as poor rheological behavior. In this work, an innovative silica-based hybrid filler system was developed, obtaining a rubber composite with an improved set of properties. A nanosized high surface area graphite (HSAG) was functionalized with 2-(2,5-dimethyl-1H-pyrrol-1-yl)propane-1,3-diol, serinol pyrrole (SP), through a simple process characterized by a high carbon efficiency. The HSAG-SP adduct, with about nine parts of SP per hundred parts of carbon filler, was used to form a hybrid filler system with silica. An elastomeric composite, with poly(styrene-co-butadiene) from anionic polymerization and poly(1,4-cis-isoprene) from Hevea brasiliensis was prepared with 50 parts of silica, which was replaced in a minor amount (15%) by either pristine HSAG or HSAG-SP. The best set of composite properties was obtained with HSAG-SP: the same dynamic rigidity and hysteresis and tensile properties of the silica-based material and appreciably better rheological properties, particularly in terms of flowability. This work paves the way for a new generation of silica-based composites, with improved properties, based on a hybrid filler system with a nanosized edge functionalized graphite.

Combustion synthesis of Si3N4 powder

1997 ◽  
Vol 12 (3) ◽  
pp. 805-811 ◽  
Author(s):  
Wei-Chang Lee ◽  
Shyan-Lung Chung
Keyword(s):  
Reaction Mechanism ◽  
Combustion Synthesis ◽  
Combustion Temperature ◽  
Fine Particles ◽  
Minor Amount ◽  
Synthesis Reaction ◽  
Experimental Parameters ◽  
Combustion Synthesis Reaction ◽  
A Minor ◽  
Low Nitrogen

A combustion synthesis (SHS) process has been developed for the synthesis of Si3N4 powder under low nitrogen pressures. Si and NaN3 powders were used as the reactants, and NH4Cl powder was added as a catalytic agent. These powders were mixed and pressed into a cylindrical compact. The compact was wrapped up with an igniting agent (i.e., Ti + C), and the synthesis reaction was triggered by the combustion of the igniting agent. Addition of NH4Cl was found necessary for the combustion synthesis reaction under low nitrogen pressures (< 1.2 MPa). The product as synthesized is mostly in the form of agglomerated fine particles (0.1–1 μm in diameter) and is composed mainly of α-phase and a minor amount of β-phase. Effects of various experimental parameters (N2 pressure, NaN3, NH4Cl, and Si3N4 contents) on the product conversion and the combustion temperature were investigated. A possible reaction mechanism was proposed that explains the effects of the experimental parameters on the synthesis reaction.

THE EFFECTS OF TOBACCO SMOKING IN CHILDREN

PEDIATRICS ◽  
1967 ◽  
Vol 40 (3) ◽  
pp. 362-362
Author(s):  
T. E. C.
Keyword(s):  
American Medical Association ◽  
Medical Association ◽  
American Medical ◽  
Tobacco Smoking ◽  
Organic Lesion ◽  
Minor Degree ◽  
Normal Quantity ◽  
Continued Use ◽  
A Minor

The very first issue of the Journal of the American Medical Association contained the following abstract of a paper published originally in the French Revue d'Hygiene of March 20, 1883 on the evil effects of tobacco smoking in children. Dr. G. Decaisne, in a paper read before the Paris Société de Médicine Publique, gives observations upon thirty-eight children, between nine and fifteen years of age, where decided effects [due to smoking] were produced in twenty-seven. Twenty-two had disturbances of the circulation, bruit de souffle in the carotids, palpitation of the heart, difficulty in digestion, indolent intelligence and a decided taste for strong drinks. Thirteen had an intermittent pulse. Eight showed a notable diminution of blood corpuscles. Twelve had frequent attacks of nosebleed. Ten were restless in their sleep with nightmares. Two showed slight ulcerations of the buccal membrane, which disappeared promptly on their giving up smoking for a few days. In one case pulmonary phthisis seemed to have resulted from a profound alteration of the blood due to the long continued use of tobacco. In eleven children who gave up smoking entirely, with six these symptoms disappeared in less than six months; three still suffered in a minor degree at the end of a year. He concludes, as the result of his observations collected through twenty years, that the pernicious effects of smoking upon children are incontestable. That it produces intermittence of the pulse, alteration of the blood, and the principal symptoms of chloroanemia, pallor of the countenance, emaciation, bruit de souffle in the carotids, palpitation of the heart, diminution of the normal quantity of the blood corpuscles, and difficulties of digestion. That the mental faculties become sluggish, with a fondness for strong drinks. That the ordinary treatment for chloroanemia produces no effect while the habit continues, and, finally, that with those children who are without organic lesion, all these disorders disappear promptly and without leaving any traces behind, when the habit is discontinued. Could French tobacco of the 1880's have been all that potent, or was Doctor Decaisne an alarmist?

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