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A study has been described of a comparison between reaction plateaus and kinetic modes for measuring cholesterol. A similar investigation of bilirubin reactions under the same procedural conditions was also carried out because this compound is a major interference which is frequently encountered in abnormal serums. The findings indicate that bilirubin is a more sensitive reactant than cholesterol by LB reaction but that its effect as an interference can be lessened by a kinetic approach providing that the effect of H 2 O on reaction velocity and molar absorptivity can be minimized. An iron reaction even though more sensitive proved less workable in the kinetic mode owing to reaction velocity and the presence of air bubbles. However, its reaction plateau characteristics were superior to the LB reaction because of a favorable ratio of colors generated for the two reacting constituents. Based on this study, it is predictable that a kinetic approach is quite workable for the LB reaction and could be made more workable for the iron reaction if, in the latter case, conditions perhaps such as temperature and reaction media, could be altered to slow the rate of color formation.

I. Detonation in Acetylene and Pentane Mixtures .— Observations on detonation in acetylene and pentane mixtures at ordinary pressures with the object of finding the position of detonation in a tube under set conditions, were described in the previous paper. The present paper extends this work, but at higher initial pressures and temperatures. Apart from the study of detonations in engines, and experiments in explosion bombs where the pressure rise is observed, very little appears to have been done to extend the work of Le Chatelier and of Dixon on rate of propagation of combustion to regions of high pressure. The highest pressure at which explosions were photographed by Le Chatelier and by Dixon were about one and a half to two atmospheres. Woodbury, Canby and Lewis using a bomb of 12 inches length succeeded in photographing explosions in acetylene air mixtures at pressures up to 4 atmospheres. They also investigated the effect of initial temperature (up to 125° C.). The results are referred to by Brown, Leslie and Hunn who find that for any initial density or pressure there should be a certain maximum value of the initial temperature to provide a maximum rate of rise of pressure on exploding a given gaseous mixture; decrease in density of charge on rise of temperature overcomes the effects of increase in reaction velocity.

Es wurden 2-Anilino-5-aryl-1,3,4-oxadiazole in Essigsaure bromiert, wobei nur ein Bromatom in Parastellung zur aromatischen Aminogruppe eingefuhrt werden konnte. Die an dieser N-Gruppe acetylierten Verbindungen widerstanden der Bromierung. Daraus wird geschlossen, das der 5-Phenyl-1,3,4-oxadiazol-Rest elektronenziehenden Charakter hat. Fur die einzelnen Verbindungen wurde die Reaktionsgeschwindigkeit der Bromierung errechnet. Bromination of Some 2-Anilino-5-aryl-1,3,4-oxadiazoles 2-Anilino-5-aryl-1,3,4-oxadiazoles were brominated in acetic acid. Only one atom of bromine in para position to the aromatic amino group could be introduced. The acetylated compounds on this N-group resisted bromination. Therefor it was concluded that the 5-phenyl-1,3,4-oxadiazole group has an electron drawing effect. For the single compounds the reaction velocity of bromination was determined.

Die Bildung der Thiospinelle MnCr2S4, ZnCr2S4 und CdCr2S4 bei der Festkorperreaktion von MnS, ZnS und CdS mit Cr2S3 wurde mit Hilfe von Leitfahigkeitsmessungen verfolgt. Aus den Leitfahigkeitsisothermen und den „Glowkurven”, die bei zeitlinearer Aufheizung der Reaktionsgemische erhalten werden, konnten wir quantitativ den Beginn der Umsetzung, die Geschwindigkeit der Festkorperreaktion und die Temperaturabhangigkeit der Reaktionsgeschwindigkeit bestimmen sowie die einzelnen Phasen der Reaktion aufzeigen. Wahrend in den Leitfahigkeitsisothermen neben einer charakteristischen, von der Umsetzung verursachten Leitfahigkeitsabnahme mit der Versuchszeit eine Reihe weiterer Vorgange, die mit der eigentlichen Reaktion nicht in Zusammenhang stehen, beobachtet werden, ist in den Leitfahigkeitsglowkurven lediglich ein fur diese Versuchsfuhrung typisches Maximum enthalten, das mit zunehmender Aufheizgeschwindigkeit zu hoheren Temperaturen verschoben wird. The formation of the thiospinels MnCr2S4, ZnCr2S4 and CdCr2S4 by solid state reaction of MnS, ZnS and CdS with Cr2S3 was investigated by electrical conductivity measurements. The conductivity of at constant temperature annealed sulfide mixtures (conductivity isotherms) and the “glow” curves, found at linearly increasing temperature, indicate the onset of the reaction, the velocity of the transformation, and the temperature dependence of the reaction velocity as well as the particular stages of the reaction course. Unlike the conductivity glow curves, showing only a maximum typical for these experimental conditions, the conductivity isotherms show, in addition to a characteristic decrease of the conductivity during the real reaction, some more effects not related to the transformation of the thiospinel.

(1) From the experimental study of the nitrogenation of calcium carbide the author concluded its mechanism to be as follows: (a) adsorptions of nitrogen on the carbide, (b) formation of intermediate compound Ca(CN)2 temporarily, (c) breaking of Ca(CN)2 into CaCN2 and C. (2) Equations for this (gas-solid) reaction velocity were derived from above view. For constant temperature and pressure (Remark: Graphics omitted.) and for changing pressure (Remark: Graphics omitted.) (3) The coincidence of these equations with the experimental results were discussed. (4) The heat of activation for the reaction of the adsorbed nitrogen and carbide to form calcium cyanide was calculated to be approximately 86 Cal./mol.

As the factors influecing on the process of reaction (1) of cyanuric chloride with alcohols, the reactivities of alcohols and the effect of-OR in (2) and (3) on the reactivity of residual chlorine atom have been investigated from estimation of reaction velocity constant and evolved CO2in the presence of CaCO2The reactivities of alcohols were found to be decreased in the order of CH3OH>C2H5OH>η-C4H9OH>η-C3H7OH>iso-C3H7OH, and the deactivation effect of the substituent groups were in order of -NH2 (-NHAr)>-OR>OAr, -0C2H5>-OCH3.The reactions (1) with various alcohols have been observed at various temperatures and reaction curves were obtained.The results indicated that the reactions were proceeded stepwise.Optimum temperatures for obtaining (2) and (3) were clarified.

Die Anwendung photochemischer Grundtatsachen (photochemischer Primarprozesse, Reaktionsgeschwindigkeit, Anzahl der Quanten nach scheinbar vollstandiger Absorption, Photosensibilisierung usw.) auf die Lichtreaktionen der Haut wirft eine Reihe von Problemen auf, deren Losung durch die komplexe Natur eines Gewebes wie der Haut sehr schwierig erscheint. An einigen, vor allem an einfachen Modellen gewonnenen Beispielen wird der augenblickliche Stand der Kenntnisse skizziert. Fundamental Physico-Chemical Aspects of the Action of Light on Skin Application of basic photo-chemical principles (primary photochemical processes, reaction velocity, number of quanta after apparently complete absorption, photo-sensibilization etc.) on the reaction of skin towards light is associated with a number of problems, whose solution appears to be very difficult, owing to the complex nature of the tissue involved like skin. The information gathered uptil now is presented mainly with the help of a few model examples.

(1) An interpretation on the real meaning of the observed oxidation velocity of ferrous hydroxide under the conditions of the author’s experiments was given to prevent misunderstanding of the author’s papers. (2) The reason, why the experimental conditions, under which the author’s measurements were carried out, were adopted, was described. (3) It was discussed that the oxidation velocity of ferrous hydroxide, observed by A. Krause under quite different conditions, will have quite a different meaning as that, observed by the author. The difference of the real meaning of the observed reaction velocity, caused by the difference of the experimental conditions, will explain why the effect of temperature, which was negligible under the author’s conditions, was found by A. Krause to be very great.

Velocity of angiotensin formation has been studied using normal rat plasma and plasma from acute mercuric chloride intoxicated rats as renin substrate material. When the reaction velocity at the constant renin concentration is plotted for various concentrations of angiontensinogen, both substrate materials yielded identical velocities. Influence of plasma from mercuric chloride intoxicated rats upon the velocity of angiotensin formation from normal rat plasma was also examined. Plasma from acute mercuric chloride intoxicated rats did not affect the velocity of angiotensin formation from normal rat plasma and vice versa. These results suggest that acute mercuric chloride intoxication may neither reduce inhibitor(s) nor release activator(s) in plasma which influence the renin-angiotensinogen reaction. The mechanism responsible for augmented pressor response to the exogenous renin in acute mercuric chloride intoxicated rats was discussed.

The Michaelis constants and maximum reaction velocity values for butyrylcholine, acetoacetylcholine, β-hydroxybutyrylcholine and crotonylcholine were determined using purified horse serum cholinesterase. The methods used for the synthesis of the above compounds are also described.

The effect of EDTA was observed on the hydrolysis of IMP by an alkaline phosphatase of carp muscle. Results obtained may be summarized as follows: 1. EDTA depressed not only instantaneously the initial reaction velocity, but also time-dependantly the reaction velocity of IMP hydrolysis by the phosphatase. (Fig. 1) 2. The instantaneous effect of EDTA was apparently removed by the addition of excess Mg++. (Table 1 and Fig. 2) 3. During the preincubation of the phosphatase with EDTA, the activity, which was deter-mined after the removal of the EDTA effect by the addition of excess Mg++, was gradually de-creased. (Fig. 3) That is, the phosphatase was gradually inactivated irreversibly by EDTA. 4. The phosphatase was denatured by heat at a lower temperature in the presence of EDTA than in the absence. (Fig. 4) 5. From these results, EDTA was supposed to inhibit the phosphatase reaction by such mechanisms, that EDTA may combine instantaneously and reversibly with a metal ion which is essential to the phosphatase reaction, and the metal free phosphatase thus occurred may gradu-ally and temperature-dependantly be denatured.

The reaction of Hg(3P1) with ethylene at room temperature has been re‐investigated. Special attention was paid to the effects of the concentrations of ethylene and mercury on the reaction velocity. The results are in general agreement with a mechanism which requires the excited ethylene, produced initially, to decompose both in the gas phase and on the wall. The results are also compatible with the suggestion that a significant fraction of the quenching collisions between ethylene and Hg(3P1) leads to the formation of metastable (3P0) atoms.

Neutral and alkaline solutions in water of the nitrophenyl phosphates are very stable in the dark. These compounds, however, and the meta derivative in particular were found to undergo a remarkable rapid hydrolysis when exposed to visible or ultra-violet light. The reaction velocity is independent of the hydrogen ion concentration at pH's between 3 and 12 but increases strongly at higher pH's. Nitrophenol and phosphoric acid could be traced as the products of this photochemical reaction. The reaction proved to be zero order; the rate did not change upon varying of the temperature from 25° to 40° C. The nitrophenyl sulphates show an analogous behaviour but for the fact that the increase of reaction rate at higher pH's does not occur and that the difference in the rate of photochemical reaction between the meta compound on the one hand and the ortho and para derivatives on the other hand are even greater than with the phosphates. The experimental evidence points to a purely photochemical (non sensitized) reaction, the nature of which is tentatively discussed.

Die Abhangigkeit der Reaktionsgeschwindigkeit bei der Bildung von polymeren Peroxyden des Methylmethacrylats von der DK des Reaktionsmediums last sich mit Hilfe der theoretischen Ansatze fur polare Reaktionen beschreiben. Danach gilt: wobei durch die Grose E′e elektrostatische Wechselwirkungen zwischen den Reaktanten im Ubergangszustand berucksichtigt werden. Mit einem fur das Monomere spezifischen Wert von E′e lassen sich die Versuche mit den verschiedensten Losungsmitteln mit befriedigender Genauigkeit wiedergeben. Die experimentell gefundene Abhangigkeit der Bruttoaktivierungsenergie von der DK zeigt die theoretisch zu erwartende Richtung, ist allerdings in ihrem Absolutwert groser als die unter vereinfachenden Annahmen aus anderen kinetischen Daten berechnete. Die experimentell je nach der DK des Losungsmittels verschieden gros gefundene Reaktionsordnung bezuglich des Monomeren last sich mit der angegebenen theoretischen Behandlung auf eine im Idealfall vorliegende 1. Ordnung zuruckfuhren. The influence of the dielectric constant of the reaction medium on the reaction velocity in the case of the formation of polymeric peroxides from methylmethacrylate can be described by the use of the kinetic formulations for polar reactions. Therefore, it holds: where E′e stands for the electrostatic interaction energy of the reactants in the transition state. With one value for E′e which is specific for the monomer all the experiments with a variety of different solvents can be represented with satisfactory accuracy. The experimentally determined dependence of the activation energy from the dielectric constant shows the theoretically expected direction. Its absolute value, indeed, is somewhat higher than the theoretical, which is derived from other kinetical data. The order of reaction which is found experimentally to vary with the dielectric constant of the solvent, can be reduced to the case of the ideal first order by the use of the given theoretical treatment.

The rate of reaction of iron and hydrogen sulfide has been studied in an oxygen-free system in the presence of sodium chloride brine, in the presence and absence of an oil phase under a constant mixing rate at 40 G and 80 C. The experimental data are plotted according to a previously derived equation for the iron-acetic acid system, and are shown to be in agreement with that equation. Values of K, the overall reaction velocity, are obtained from the slopes. From the K values for three sets of experiments at 40 C and 80 C, values for the temperature coefficient are calculated, and are shown to correspond to the range of values expected for diffusional control. The presence of an oil phase seems to have little influence on the reaction rate. Another group of measurements on the iron-hydrogen sulfide system was carried out in the presence of corrosion inhibitors. While all the data of the inhibited reactions will show reasonable straight line plots, when plotted according to the diffusional equation, such plots have little meaning with the good inhibitors, because there is no essential change with time in the loss-in-weight values when they are used at 50 ppm. There seems to be some possibility that good inhibitors function by forming a particularly efficient non-permeable adsorbed film with iron sulfide corrosion products. 6.2.2

When a moderately strong solution of sodium nitrite is added to blood a change of colour almost immediately occurs, mainly owing to the formation of methæmoglobin. The actual products of the reaction are not definitely known, and are not of importance to the present paper. The rapidity of the reaction is affected by the nature and concentration of the blood solution on the one hand, and by the concentration of the sodium nitrite solution on the other. Probably other factors, such as temperature, which has not been investigated, are of importance. The experiments referred to in this paper were made at room temperatures.

The preparation and properties of two new, highly reactive aluminum hydroxide–magnesium carbonate dried gels (AHMC) are described. The rate of reaction with gastric acid is shown to be rapid as well as prolonged in the optimum pH range of 3 to 5. Three methods were used to determine reaction rate including the Reheis and Mutch reaction velocity tests as well as a modified procedure of Holbert, Noble, and Grote. An automated apparatus for antacid evaluation is described. Data on thirteen antacid chemicals as well as thirty of the most widely used antacids in liquid and tablet form are presented. The in vitro antacid properties of AHMC dried gels compares favorably with reactive liquid aluminum hydroxide gel. The aging characteristics are shown to be excellent.

The homogeneous first order gaseous decomposition of paraldehyde to acetaldehyde has been studied at temperatures from 230 to 254 °C. up to pressures at which the liquid phase makes its appearance, i.e., 12 atm. at 230° and 18 atm. at 254 °C. Over-all velocity constants for the homogeneous reaction in the heterogeneous liquid-vapor system have been determined from these pressures up to the critical point. The data confirm results already published. It is found that in the purely gaseous system increase of pressure tends to diminish the reaction velocity. That the specific reaction velocity in the liquid phase is greater than that in the vapor phase is shown by the fact that the velocity constants of the heterogeneous systems increase progressively with the liquid-vapor ratio. Extrapolation to 100% of liquid gives velocity constants about five times as great as those characteristic of the vapor phase. Peculiarities in the behavior of the system at the critical point and preliminary measurements of the velocity of the trimolecular reverse reaction are described.

Estimation of the volume of hydrogen consumed by a static method with Cu-Cr-O under atmospheric pressure of hydrogen at 180°C by hydrogenation of whale oil was-studied kinetically. It was observed that the reaction is zero order to the concentration of the molecule to be hydrogenized, and, in spite of it, the reaction velocity gradually decreases due to the reversible poisoning of catalyst. An assumption was made that a poisonous substance is formed in the process of catalysis, and that its amount is proportional to the degree of hydrogenation. The following formula is presented. dx/dt=K_1(N_o-K_2x)

Im Gegensatz zu der Hydrolyse von Clupein mit Mineralsauren, welche gleichmasig fortschreitet. wird beim Abbau mit langkettigen Alkylsulfonsauren und Alkylschwefelsauren schon bei niedrigen Spaltungsgraden eine Anzahl charakteristischer Abbaustufen beobachtet. wahrend welcher die Hydrolyse nahezu zum Stillstand kommt. Die Lage dieser Abbaustufen ist abhangig von der Konzentration der angewandten Saure. Das Auftreten solcher Perioden verminderter Reaktionsgeschwindigkeit wird mit der Annahme einer intermediaren Bindung der die Hydrolyse beschleunigenden Anionen an gebildete Spaltprodukte zu erklaren versucht. Whereas the hydrolysis of clupein by mineralic acids proceeds constantly, in the case of the hydrolysis by long-chain alkylsulfonic acids and alkylsulfates a number of reaction steps is observed during which the hydrolysis nearly comes to a stand-still. The position of these steps is found to be dependent upon the concentration of the acid used. The existence of such periods of decreased reaction velocity is explained by the assumption that an intermediary binding of the catalyzing anions to certain protein split products takes place.

1. 1. An automated method was developed for the estimation of enzymatic activities based on the slope measurement of linear reaction curves. The procedure is applicable to most spectrophotometric assays, even when enzymatic reaction velocity is measured by means of a subsequent chemical reaction. 2. 2. The method was developed in the particular case of soluble starch hydrolysis by rat pancreatic amylase, estimated by the reduction of 3,5-dinitrosalicylic acid. Good kinetic graphs were obtained at a rate of 12 assays per hour for 1.8 min recording time.

Durch Messung der Fluoreszenzspektren wurde die Dissoziationsreaktion im angeregten Zustand von funf Ammoniumderivaten des Pyrens in Methanol, Athanol, n-Propanol und n-Butanol im Temperaturbereich zwischen Zimmertemperatur und 100 °K untersucht. Die Ammoniumpyrene sind im angeregten Zustand sehr starke Sauren mit Dissoziationskonstanten zwischen 102 und 102 Mol/l. Der experimentelle Befund, das die Reaktionsgeschwindigkeit und ihre Temperaturabhangigkeit eine Funktion des Losungsmittels ist, von der Saurestarke aber nicht abhangt, wird durch die Annahme gedeutet, das bei der unter Gewinn an freier Energie verlaufenden Protolyse starker Sauren die (teilweise) Umsolvatation geschwindigkeitsbestimmend ist. The rate of dissociation of five ammonium derivatives of pyrene in the excited state has been examined in methanol, ethanol, n-propanol and n-butanol at temperatures between room temperature and 100 °K by the measurement of fluorescence spectra. In the excited state the ammoniumpyrenes are very strong acids, with dissociation constants between 102 and 106mole litre−1. It is found that the reaction velocity and its temperature coefficient depend on the nature of the solvent but not on the strength of the acid. This is explained by the assumption that the partial change in solvation determines the velocity of the protolysis of strong acids, a reaction accompanied by a gain in free energy.

By use of several kinds of aliphatic and armatic acid hydrazides, reactions between acid hydrazides and that of acid hydrazide and acid amide were carried out.Unreacted components were determined by the method given in this first report and the reactiveness in each case has been investigated. It was confirmed that the reaction for formation of aminotriazole from acid hydrazide was the second order reaction. The reaction velocity constant was greater in those having less carbon atoms in case of aliphatic compounds while the reaction velocity was greater in those having more carbon atoms in aromatic acid hydrazides having 6, -40 carbon atoms. With the assumption that the reaction for formation of triazole from acid amide and acid hydrazide is similarly the second order reaction, the velocity ratios for formation of aminotriazole and triazole were investigated and found that the rate of formation of triazole was slower than aminotriazole.

流動層反応装置を使用して石炭の空気酸化 (主に200～300℃) に関する2, 3の問題を考察した。酸化による石炭の性質の変化を知るために粘結性 (ボタン法), 揮発分, 重量変化, フミン酸測定などを行い, これらの結果から酸化生成物の性質は石炭の種類および酸化温度によつて異ることを述べた。また反応速度および機構について述べ, R-r=kθの式を導いた。

If ethylene–vinyl acetate copolymers are converted with aluminum alcoholates, crosslinked products will form. This reaction was studied on the basis of the viscosity variation and the amount of acetic acid ester formed. The constants of the reaction velocity for the conversion with various aluminum alcoholates were determined and a reaction mechanism is discussed.

水溶性部分シアノエチル化ポリビニルアルコールの微アルカリ性過酸化水素によるカルバミルエチル化に関する前報の実験結果および若干の追加実験結果に基いて, カルバミルエチル化度, カルボキシエチル化度および脱エーテル化度を計算した。また, カルバミルエチル化について反応速度論的考察を行い, 微少なカルボキシエチル化度を無視して, カルバミルエチル化度に一つの極大をもつ次式が近似的に適用されることを認めた。x=ae-k2t(1-e-k1t)aは-CN基の初濃度,xはt時間後に生成された-CO・NH2基数,k1およびk2はそれぞれカルバミルエチル化および脱エーテル化反応を1次式によるとした場合の反応速度定数。なお,k1/k2は500～1000程度と推定された。

Two strains of rats with opposite genetic propensity for hypertension were tested for: (a) the sensitivity to injections of angiotensin and renin, and (b) the influence of their plasma on the reaction velocity of renin and its substrate in vitro. Intact hypertension-prone (S) rats on low salt had higher sensitivity to angiotensin and a lower sensitivity to renin than hypertension-resistant (R) rats. High NaCl diet did not change the response of the R rats to these injections, but increased the response to renin and angiotensin in intact S rats. Bilateral nephrectomy caused increased response to renin and a decreased response to angiotensin in the S rats, so that both strains were equivalent after bilateral nephrectomy. In vitro, plasma from intact S rats inhibited the activity of hog renin. Plasma from R rats showed no inhibition. The inhibitor disappeared after bilateral nephrectomy. It was speculated that renin inhibitor may be involved in the development of hypertension by increasing sensitivity to angiotensin and other hypertensinogenic stimuli.