Yields Of Reaction Products Research Articles

The photolysis of n‐butyraldehyde in isooctane at 313 nm

AbstractThe effects of aldehyde concentration, incident light intensity, and temperature on the quantum yields of reaction products were studied. Mechanisms for primary and secondary photochemical processes were suggested, and primary quantum yields as well as rate constant ratios were derived. Reversibility of intramolecular γ‐hydrogen transfer and disproportionation of the radical pair formed in the reaction of an excited triplet and ground state molecule were shown to provide important pathways for radiationless decay of the triplet state.

Upper limits for theAl27+O16andNb93+O16radiative-capture cross sections

Thick targets of high purity aluminium and niobium were bombarded with /sup 16/O ions in the energy range 50--65 MeV. The yields of reaction products were obtained off-line using a Ge(Li) detector to observe residual ..gamma.. activities. Ungated ..gamma.. spectra in coincidence with pairs of 511 keV annihilation quanta, observed in an array of four 7.5 x 7.5 cm NaI(T1) detectors, were recorded. Upper limits of 0.2 ..mu..b and 0.1..mu..b were obtained for the /sup 27/Al(/sup 16/O,..gamma..)/sup 43/Sc and /sup 93/Nb(/sup 16/O,..gamma..)/sup 109/In radiative capture cross sections, respectively. These limits are compared to previously reported data and to the results of statistical model calculations. It is concluded that some previously reported total heavy-ion radiative capture results may be in error and tentative explanations for this are offered.

ChemInform Abstract: OXIDATION OF ALKENES WITH USE OF PHASE TRANSFER CATALYSIS

AbstractDie Oxidation langkettiger Olefine mit wäßrigem Kaliumpermanganat im neutralen und alkalischen Medium sowie mit wäßrigem Rutheniumtetroxid wird durch Zusätze von Phasentransferkatalysatoren in der Reaktionsgeschwindigkeit beschleunigt und in der Ausbeute erhöht.

Oxidation of alkenes with use of phase transfer catalysis

Abstract and summaryThe use of phase transfer catalysis (PTC) as an aid in the oxidation of long chain olefins with aqueous potassium permanganate (KMnO4) in neutral and alkaline media and with aqueous ruthenium tetroxide (RuO4) is reported. The phase transfer catalysts (PTCT) were either quaternary ammonium halides or crown ethers. The long chain olefins studied were 1‐pentadecene, 9‐octadecene, and methyl oleate. PTC not only increases the rate of these reactions but also gives good yields of reaction products. For example,cis‐9‐octadecene in methylene chloride reacted with aqueous KMnO4 to give either dihydroxyoctadecane (80%) or pelargonic, acid (80%) depending upon pH, when tetrabutylammonium bromide was used as the PTCT. When RuO4 in conjunction with a PTCT was used as the oxidant, a quantitative yield of myristic acid was obtained from 1‐pentadecene. The RuO4 oxidant was conveniently regenerated in situ from RuO2 and sodium hypochlorite. This regeneration is facilitated with a PTCT.

Furan Derivatives 90. A New Nucleophilic Substitution in Furan Series

Abstract The Knoevenagel condensation of 5-arylthio-, 5-heteroarlthio- and 5-arylsulphonyl-2-furaldehydes, respectively, with malonitrile in ethanol in the presence of basic catalysts (sodium ethoxide) gives rise to corresponding α, β-unsaturated compounds1. Now, we have found a different course of the condensation, when saturated heterocyclic secondary amines (piperidine, morpholine, pyrolidine and N-methylpiperazine) as catalysts were used. In the first step of this reaction the normal condensation product i.e. 2-cyano-3-(5-arylthio-2-furyl)-, 2-cyano-3-(5-heteroarylthio-2-furyl)- and 2-cyano-3-(5-arylsulphonyl-2-furyl) acrylonitrile is formed which further reacts according to the SN mechanism with the present secondary amine to the appropriate 5-aminoderivative. In order to increase the yields of reaction products, the condensation was carried out with equimolar amounts of aldehyde, malonitrile and secondary amine in absolute ethanol at room temperature (Reaction 1).

Reaktionsgaschromatographie: Ein mittel zur raschen abschätzung von reaktionsparametern: I. Beispiele für amidierungen und N-acylierungen

Reaction gas chromatography: a method for the rapid estimation of reaction parameters. I. Amidations and N-acylations A special application of reaction gas chromatography is described using the injection heater as chemical microreator. A mixture of volatile reactants is introduced into the injection port of a commercial gas chromatograph and the products formed in the injection heater are separated on the column. This method is a useful aid in the estimation of reaction parameters and the experiments can be performed in any commercial gas chromatograph without any auxiliary apparatus. The influence of various reaction parameters, such as molecular ratio, temperature and residence time in the injection heater, can be studied, as well as the effect of catalysts and solvents. The resulting yields of reaction products under various experimental conditions give an indication of the reactivity. This method is also a valuable tool for the investigation of unknown reactions.

Alkylation of adamantane and 1,3-dimethyladamantane using alumina catalysts

ALKYLATIO~ of adamantane with olefms and alcohols is an important method of obtaining alkyladamantanes with different side chain lengths. Existing methods of alkylation, however, are not effective enough. Thus, alkylation of adamantane with olefins over aluminium halides even at low temperatures is accompanied by marked isomerization and oligomerization, as a result of which fairly complex product mixtures are formed [1]. In some cases, for example, during alkylation with cyclopentene, when isomerization cannot produce new substances, the yield of the end product (cyclopentyladamantane) reaches 65% with high selectivity [2]. Although alkyladamantanes of the same molecular weight can be obtained by alkylation of adamantanes with alcohols and olefins over sulphuric acid, the overall yield of reaction products does not exceed 9-25% of reacted adamantane [3, 4]. In a previous paper we proposed to use paraffin as alkylating agent [5]. Conjugate reactions of breakdown of paraffin and alkylation of adamantanes by fragments formed take place in this case over aluminium halides. When using, for example, 2,2,4-trimethylpentane, isomeric monobutyl-and dibutyladamantanes can be obtained in one stage with an overall yield of approximately 80%. The composition of reaction products obtained by this method depends on features of decomposition of the paraffin hydrocarbon. In order to develop more efficient methods for the synthesis of alkyladamantanes, particularly of high molecular weight, alkylation of adamantane and its lower homologues was examined over acid catalysts prepared using alumina. I t is well known that by isomerization catalysts of this type activate saturated tricyclic hydrocarbons, including alkyladamantanes [6, 7]. Results are given in this paper obtained by alkylation of adamantane and 1,3-dimethyladamantanc over alumina activated with sulphurie acid, a Houdry type aluminosilicate catalyst and Zeokar-2 and AShNTs-3 industrial catalysts containing zeolite. C2-Cs alkylating agents and some alcohols and alkyl halides were used as alkylating agents.

Heterogeneous-catalytic fischer reaction

The catalytic synthesis of 7-azaindole and its 2-methyl derivative has been accomplished for the first time by cyclization of acetaldehyde and acetone 2-pyridylhydrazones in the presence of γ-Al2O3 and fluorinated aluminum oxide. The temperature dependence of the yields of reaction products — azaindoles and 2-aminopyridine — was studied. The cyclization of acetaldehyde 2-pyridylhydrazone proceeds under more severe conditions. The maximum yield of 7-azaindole is 15% at 450° on fluorinated aluminum oxide. The yield of 2-methyl-7-azaindole reaches 50% at 315°. Fluorinated aluminum oxide displays higher catalytic activity.

The Lithium Phenoxide Catalyzed Addition of Propylene Oxide to Phenol

Addition of propylene oxide to phenol with lithium phenoxide as a catalyst was studied under various temperature as well as composition conditions. The kinetic study of this reaction rules out an ionic mechanism and proposes instead a multi-centred reaction in which the three component associated transition complex rearranges to yield reaction products. Arrhenius parameters in the case of lithium phenoxide exhibit marked deviations from those of homologue alkali phenoxides: there is an abrupt and unusually high decrease in the activation energy accompanied by a corresponding decrease in the frequency factor, the reaction velocity remaining almost unchanged. This compensation effect takes place as a result of a multi-centred reaction in homogeneous phase.

Reactions of methylaluminium compounds with methacrylonitrile

Reactions of trimethylaluminium, dimethylaluminium chloride and methylaluminium dichloride with methacrylonitrile have been investigated. These reactions afford corresponding donor-acceptor complexes. At elevated temperatures they react to yield methyl isopropenyl ketone (upon hydrolysis) and oligomers. During these reactions methane is formed in small amounts. The yield of reaction products has been studied in relation to the nature of methylaluminium compound and the reaction temperature.

Factors affecting lead capture methods for the fine localization of rat lung acid phosphatase.

Gomori's lead capture method for acid phosphatase localization was adapted for the electron microscope by Holt & Hicks (1961a). The method gave good results in rat liver, but poor tissue preservation with no reaction product in rat lung, and was, therefore, investigated in order to find the optimum conditions for the ultrastructural localization of rat lung acid phosphatase. The conditions investigated included the use of glutaraldehyde or depolymerized paraformaldehyde as the fixative, with and without dimethylsulphoxide; the effect of freezing the tissue; the pH of the incubation medium; and the use of glycerophosphate, naphthol AS-BI phosphate or α-naphthyl phosphate as substrates. Improved preservation of ultrastructure with increased yield of reaction product was obtained by prefixing lung in glutaraldehyde containing 10% dimethylsulphoxide, freezing the tissue and incubating at pH 5.7 with α-naphthyl phosphate. Tissue preservation was acceptable and dense deposits of reaction product occurred in lysosomal elements of all the alveolar cells and especially in macrophages. Deposits were also found closely associated with the lamellae of the inclusion bodies of Type II cells.

Study ofBe9(Li7, p),Be9(Li7, d),Be9(Li7, t), andBe9(Li7, α)Reactions from 5.6 to 6.2 MeV

Absolute differential cross sections at angles ranging from 10\ifmmode^\circ\else\textdegree\fi{} to 170\ifmmode^\circ\else\textdegree\fi{} and at bombarding energies of 5.6, 5.8, 6.0, and 6.2 MeV have been measured for the reaction ${\mathrm{Be}}^{9}$+${\mathrm{Li}}^{7}$, leading to each of the following states: ground and 0.75-MeV states of ${\mathrm{C}}^{15}$; ground, 6.10, 6.58 with 6.72, 6.89 with 7.01, 7.34, and 8.32-MeV states of ${\mathrm{C}}^{14}$; ground, 3.09, and 3.68 with 3.85-MeV states of ${\mathrm{C}}^{13}$; ground, 0.95, 1.64, and 2.62 with 2.72-MeV states of ${\mathrm{B}}^{12}$. The yields of the ${\ensuremath{\alpha}}_{0}$ and ${\ensuremath{\alpha}}_{2}$ groups at 20\ifmmode^\circ\else\textdegree\fi{} (lab) have been measured at 3.3 MeV and at eleven other energies ranging from 5.0 to 6.2 MeV. Absolute cross sections were obtained by comparison of the yields of reaction products to elastic Coulomb scattering. Comparison is made of the total cross-section values with the ($2J+1$) rule. The angular distributions for the ${t}_{0}$ and ${t}_{1}$ groups, at each of the bombarding energies, are compared with the predictions of a two-mode (pickup and heavy-particle stripping) direct-reaction process in the plane-wave approximation.

A Mechanistic Approach to the Electrolytic Reductive Dimerization of Acrylonitrile

Abstract The electrolytic reductive dimerization of acrylonitrile was investigated extensively especially in order to obtain some mechanistic information. The essential point of this reaction exists in the selective formation of adiponitrile under relatively wide conditions and this cannot be explained by a normal kinetic treatment based on the reaction scheme which has been accepted as probable. The heterogenuity in acrylonitrile concentration in the reaction system is assumed and the kinetic formulas are modified. This treatment explains the experimental results very satisfactorily. In order to confirm this mechanistic scheme, the effects of temperature, pH and solvents on the yield of reaction products were examined. All the results are consistent with the proposed mechanism.

Isolation of dinuclear dihydroxydiphenylmethanes and trinuclear novolacs (triphenylols) from phenol‐formaldehyde condensations

AbstractPrevious work has shown that the intermediates in the formation of resins from phenol and formaldehyde— the 2,2′‐, 2,4′‐ and 4,4′‐dihydroxydiphenylmethanes can only be isolated from the reaction products in small yields and with difficulty.It is now shown that after distillation of excess phenol and formaldehyde from the initial reaction mass at atmospheric pressure, a further high‐temperature steam distillation yields approximately 60% of the remaining product as white crystalline dihydroxydiphenylmethanes, 20% as triphenylols varying from hard crystalline masses to slowly crystallising oils, and 20% of fusible and soluble novolac resin of high melting point.Some lens‐shaped crystals were also obtained.

The reaction of oxygen atoms with neopentane and other alkanes: Mechanism and rates

The reaction of oxygen atoms with neopentane and other alkanes has been studied in the gas phase at 30°C. The results of this investigation support the view that the reaction products are formed by direct displacement of two groups on the parent hydrocarbon with the attendant formation of a carbonyl bond rather than by a free radical mechanism involving hydrogen abstraction. Insertion of the oxygen atom into a C−H bond also does not appear to play a major role. The over-all rates of the reaction of oxygen atoms with n-butane, isobutane, and neopentane, as well as the rates of several primary reactions have been calculated from the observed variations of the yields of reaction products with initial hydrocarbon concentrations. The values of the over-all rates for n-butane, isobutane, and neopentane were found to be 1.1×10−14, 0.6×10−14, and 0.3×10−14 cm3 molecule−1, sec−1, respectively, at 30°C.

Investigations on syntheses “under physiological conditions”: I. Comparison of the behaviour of ammonia and methylamine as one of the reaction components

AbstractThe behaviour of the following six combinations of compounds has been studied “under physiological conditions”: glutaraldehyde or succinaldehyde, methylamine or ammonia, acetonedicarboxylic acid or diethyl acetonedicarboxylate. The pH was maintained at 3, 5, 7, 10 or 13; the other experimental conditions were the same in the series with acetonedicarboxylic acid and in those with diethyl acetonedicarboxylate as reaction component. The yield of reaction product was in each case determined carefully.Ammonia proved to be well suited as reaction component in these Schöpf syntheses. The relation between the pH and the yield of reaction product in the six cases was discussed in detail; ammonia and methylamine proved to behave in the same way.

Target polarization effects in nuclear reactions

Abstract Considerations of direct reactions, based on a distorted-wave formalism, show that the effects of polarized targets represented by the tensor, ϱkκ(a), correlated to the polarization of the residual nucleus, represented by ϱkκ(b) when the target is unpolarized, provided that the transferred total angular momentum j is unique. Two related processes are considered: (1) A beam of unpolarized particles is incident on an unpolarized target and the angular dependence of the reaction-product yield associated with each tensor ϱkκ (a) is measured. (2) With no polarization in the entrance channel, the angular dependence of the polarization of the residual nucleus is measured by identifying the coefficient of the Ykκ(ϑγ, φγ) in the triple angular correlation involving the incident beam, the reaction product and the de-excitation gamma radiation. It is found that these angular dependences are identical; furthermore the relative magnitudes of the partial cross sections in (1) and (2), for a given reaction-product angle, lead to a determination of j. Polarization tensors ϱkκ(a) of rank k > 2jmax should not affect the angular distributions. No detailed assumptions are made concerning the nature of the projectile or reaction product, nor the spin-dependence of either the interaction or the channel distortions, except that such distortions be independent of the spins of the target and residual nuclei. Upper bounds may also be given, provided that j is unique, to both the magnitudes of the asymmetry in the angular distributions associated with a given polarization tensor and the magnitudes of the polarization of the residual nucleus. For a given rank of polarization these upper bounds are functions merely of a, b, and j. In several cases, because of the accidental vanishing of Racah coefficients. selection rules may be given for polarization effects of a particular rank. The polarization correlation applies to a variety of direct processes, including knock-on phenomena. Experiments are proposed which help to disentangle direct-stripping amplitudes from those normally referred as involving heavy-particle stripping where the polarization correlation is not simple unless additional assumptions are made concerning the spin dependence of optical-model potentials. It is demonstrated that provided j is unique, a series of measurements with polarized projectiles incident on polarized targets is sufficient to overdetermine the reaction amplitudes. Several processes are considered which involve spinless projectiles and reaction products and targets of integral spin. These need not be direct processes. So long as the target is appropriately polarized, observation of the reaction product, parallel or anti-parallel to the original motion, leads to a determination of the parity of the residual nucleus, and to the identification of non-zero spin states.

Destructive alkylation of benzene with pentane

1. The destructive alkylation of benzene with pentane over an aluminosilicate catalyst under autoclave conditions have effected for the first time. 2. The effects of the duration of reaction, temperature, and amount of catalysts on the yield of reaction products were investigated. 3. It was shown that destructive alkylation of benzene with an equimolecular amount of pentane under autoclave conditions results in the formation of a mixture of alkylated aromatic hydrocarbons (in an amount equal to 34% by weight of the original mixture) together with gaseous hydrocarbons (23% by weight on the original mixture). 4. The alkylated aromatic hydrocarbons obtained in the autoclave experiments were investigated, and it was shown that they included toluene, ethylbenzene, isopropylbenzene, xylenes, and ethylmethylbenzene. The gaseous reaction products were investigated and it was shown that they consisted mainly of saturated hydrocarbons.

Radiochemical investigation of spallation and fission reaction products resulting from the bombardment of bismuth with 660-Mev protons

1. Twenty-four radioactive isotopes of seventeen elements were isolated and identified in the products arising in the bombardment of bismuth with 660-Mev protons. 2. The yields of reaction products were determined. The ratio of cross sections for fission and spallation reactions was found to be about 0.07. 3. The fission reaction is preceded by the ejection. on the average. of 15–16 nucleons. In the spallation reaction 2 protons and 8 neutrons are ejected. on the average. 4. As the energy of the bombarding protons increases there Is a displacement of the yields into the stability region and also. probably. an increase in:the asymmetry of the fission of strongly excited nuclei. The results permit an estimation of the mean excitation energy of the nuclei formed as a result of the nuclear cascade process, the value found being about 90.Mev.