Alternated or simultaneous sealed-off room temperature CO/CO 2 laser tuning by chemical reactions

1991 ◽  
Author(s):  
Victor I. Masychev ◽  
Vladislav S. Alejnikov
Keyword(s):  
Chemical Reactions ◽  
Room Temperature ◽  
Laser Tuning

scholarly journals Quantum Chemical Calculation of Reactions Involving C20, C60, Graphene and H2O

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940008 ◽  
Author(s):  
N. A. Poklonski ◽  
S. V. Ratkevich ◽  
S. A. Vyrko ◽  
A. T. Vlassov ◽  
Nguyen Ngoc Hieu
Keyword(s):  
Gibbs Energy ◽  
Chemical Reactions ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Hydrogen Release ◽  
Graphene Sheets ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Chemical Calculation ◽  
Assisted Decomposition

Calculations of chemical reactions between C20, C60, hydrogen and water molecules are carried out using the PM3 method. Reactions with a hydrogen release at room temperature and atmospheric pressure are identified by the Gibbs energy change. The hydrogen release can be raised by increasing the number of water molecules in chlorine-assisted decomposition of fullerenes. Calculations of the Gibbs energy of chemical reactions involving water molecules between two parallel curved graphene sheets are carried out using DFT with the functional UB3LYP. During pumping between plates of an electric capacitor designed from curved graphene sheets, the water vapor with the assistance of external illumination is enriched by electrically neutral hydroxyl groups (OH)0.

Plasticization of Rubber in the Form of Latex

1954 ◽  
Vol 27 (1) ◽  
pp. 271-276 ◽  
Author(s):  
Marc Conté
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Reactions ◽  
Room Temperature ◽  
Ph Value ◽  
Inhibitory Effect ◽  
Rubber Latex ◽  
Adhesive Properties ◽  
Harmful Effects ◽  
Latex Rubber

Abstract When in the form of latex, rubber can be oxidized by thiols under hot conditions. The reaction apparently proceeds by the same mechanism as that characteristic in the action of peptizing agents on rubber during mastication. The results obtained confirm the hypothesis that the thiol is transformed quantitatively into the corresponding disulfide, with resultant oxidation of the rubbert. This transformation is a function of the pH value, and the best results are obtained when the pH value is around 4 and in the absence of NH4 ions (which have an inhibitory effect). Latex preparations of this type can be utilized for studying the chemical reactions of rubber in emulsion and for the preparation of rubber derivatives which are more soluble than those prepared from rubber latex which has not been degraded. In addition, such latex preparations are excellent adhesives which, in contrast to already known products (latex treated with hydrogen peroxide or other peroxides), give a sticky film by simple drying at room temperature. In this way heating can be avoided in cases where it has harmful effects and where the use of an oven is inconvenient. Finally, this type of latex is more adaptable to certain direct applications, both because of the superior adhesive properties of the rubber and because, with a relatively plastic coagulum, mastication is easier.

The Microstructure of Diene Polymers. II. Polyisoprenes and Polybutadienes Prepared at High Pressures

1954 ◽  
Vol 27 (4) ◽  
pp. 958-961
Author(s):  
W. S. Richardson
Keyword(s):  
Free Radical ◽  
Hydrostatic Pressure ◽  
Chemical Reactions ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
High Pressures ◽  
Bulk Polymerization ◽  
Extensive Investigation ◽  
Very High ◽  
Increased Pressure

Abstract The rapid bulk polymerization of isoprene at room temperature under high hydrostatic pressure was apparently first observed by Bridgman and Conant. A more extensive investigation by Conant and Tongberg established the free radical nature of the polymerization (peroxide catalysis and hydroquinone inhibition). The latter workers also noted the solubility and elasticity of polymers made to moderate conversion and the insoluble crumbly nature (gelation) of the polymers made to very high conversion. In view of the well known effect of increased pressure in driving chemical reactions in the direction of the products of least specific volume, it is of interest to consider the possibility that diene polymers made at high pressures may be different in microstructure from polymers made at comparable temperatures but near atmospheric pressure.

Synthesis and chemical reactions of some conjugated heteroenoid compounds

1967 ◽  
Vol 45 (9) ◽  
pp. 1001-1006 ◽  
Author(s):  
R. F. Silver ◽  
K. Ann Kerr ◽  
Peggy D. Frandsen ◽  
Sheila J. Kelley ◽  
H. L. Holmes
Keyword(s):  
Chemical Reactions ◽  
Room Temperature ◽  
Cyano Group ◽  
Ethyl Cyanoacetate ◽  
Geometric Configuration ◽  
Cinnamic Acids ◽  
Active Methylene Compounds ◽  
Derivatives Of ◽  
Active Methylene

A series of 326 3-benzal-2,4-pentanediones, 2-benzal-1,3-indanediones, ethyl benzalaceto-acetates, diethyl benzalmalonates, ethyl benzalcyanoacetates, benzalmalononitriles, benzalcyanoacetamides, benzalcyanoacetanilides, benzalmalonamides, β-nitrostyrenes, β-nitropropenylbenzenes, β-nitrobutenylbenzenes, and derivatives of a number of cinnamic acids have been synthesized and their geometric configuration discussed. Aniline, p-toluidine, and n-butanethiol have been added to some of these compounds. The aniline adducts have also been prepared from benzylideneaniline and the active methylene compounds. The aniline adducts of those containing a cyano group are not stable and lose aniline at room temperature. The structure of the compound prepared from benzylideneaniline and ethyl cyanoacetate and melting at 140 °C has been established.

Synthesis, chemical properties, and U.V. spectra of thio-thionyl fluoride and difluorodisulphane

1967 ◽  
Vol 20 (11) ◽  
pp. 2305 ◽  
Author(s):  
RD Brown ◽  
GP Pez
Keyword(s):  
Benzoic Acid ◽  
Chemical Reactions ◽  
Hydrogen Fluoride ◽  
Half Life ◽  
Boron Trifluoride ◽  
Room Temperature ◽  
Chemical Properties ◽  
Life Time ◽  
First Order ◽  
Silver Fluoride

The preparation of difluorodisulphane, FSSF, by the silver fluoride/sulphur reaction is described. Difluorodisulphane is unstable at room temperature and rearranges spontaneously into thio-thionyl fluoride, SSF2. The largest observed first-order half-life time of FSSP gas was 4.7 hr at 21.8 � 0.3�. The decomposition of FSSF is catalysed by hydrogen fluoride and boron trifluoride. Chemical reactions of the isomers with AgF2, Cl2, BCl3, S2Cl2, acetone, benzoic acid, Pyrex, and quartz were studied. The absorption spectra of gaseous FSSF and SSF2 were recorded in the range of 10000 to 53000 cm-1. Medium to high intensity continua were noted with maxima for FSSF at 50200�250 and 41400�250 cm-1 and for SSF2 at 53000�500, 41400�250, and 33800�400 cm-1.

scholarly journals São os azeites de oliva mais instáveis que os óleos vegetais frente ao aquecimento? Um estudo comparativo

2021 ◽  
Vol 7 (2) ◽  
pp. 165-175
Author(s):  
Aline Aparecida Ramos ◽  
Taís Júlia de Oliveira ◽  
Bruna Bellincanta Nicoletto ◽  
Gabriela Chilanti ◽  
Catia Dos Santos Branco ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Chemical Reactions ◽  
Vegetable Oils ◽  
Canola Oil ◽  
Room Temperature ◽  
Healthy Foods ◽  
Olive Oils ◽  
Acidity Index ◽  
Palabras Clave ◽  
Hydrolytic Acidity

  Resumo A procura por alimentos saudáveis está crescendo e os azeites vêm ganhando atenção. Entretanto, ainda não há consenso no que se refere às melhores formas de sua utilização na culinária. O objetivo desse estudo foi avaliar as possíveis modificações físico-químicas decorrentes do aquecimento em azeites de oliva em comparação a outros óleos vegetais. Amostras de azeites de oliva extravirgem (AOE) ou refinado tipo único (AOU); óleo de canola (OC) e óleo de soja (OS) foram selecionadas considerando as marcas mais procuradas pela população. Essas foram aquecidas a 40, 70, 120 e 180°C e analisadas quanto à rancificação hidrolítica (índice de acidez) e oxidativa (níveis de malondialdeído - MDA). Os resultados mostraram que o aquecimento foi capaz de alterar a disponibilidade de ácidos graxos livres em AOE e AOU (redução de cerca de 30 % no índice de acidez em relação à temperatura ambiente) em comparação à OC e OS. Alterações nesse parâmetro não foram observadas para os óleos. Quanto aos níveis de MDA, observou-se que tanto o AOE quanto o AOU são menos suscetíveis à termoxidação quando aquecidos, em comparação às amostras OC/OS, que apresentaram índices estatisticamente superiores. Quando comparados em conjunto, observou-se o seguinte comportamento para os níveis de acidez (AOE = AOU > OC = OS) e MDA (OS > OC > AOU = AOE). Os dados obtidos no presente estudo indicam uma maior aplicabilidade dos azeites de oliva em preparações aquecidas, no entanto, futuros estudos são necessários para melhor compreender as reações químicas envolvidas nos processos de termoproteção desses. Palavras-chave: Ácidos graxos; estabilidade; rancificação; antioxidantes.   Abstract Are olive oils more unstable than vegetable oils on heating? A comparative study Demand for healthy foods is growing and olive oils are gaining attention. However, there is still no consensus regarding the best ways to use it in cooking. This study aimed to evaluate the possible physicochemical modifications resulting from heating olive oil compared to vegetable oils. Samples of extra virgin (AOE) or refined type (AOU) olive oils; canola oil (OC) and soybean oil (OS) were selected considering the most consumed brands by the population. Samples were heated at 40, 70, 120, and 180 ° C and analyzed for hydrolytic (acidity index) and oxidative (malondialdehyde - MDA) rancidity. The results showed that heating was able to alter the availability of free fatty acids in AOE and AOU (about 30 % reduction in acidity index compared to room temperature) in relation to OC and OS. Changes in this parameter were not observed for oils. Regarding MDA levels, it was observed that both of which olive oils were less susceptible to thermo-oxidation when heated compared to OC or OS, which showed statistically higher rates. When compared together, the following behavior was observed for acidity levels (AOE = AOU> OC = OS) and MDA (OS> OC> AOU = AOE). The data obtained in the present study indicate greater applicability of olive oils in heated preparations, however, further studies are needed to better understand the chemical reactions involved in their thermoprotection processes. Keywords: Fatty acids; stability; rancification; antioxidants.   Resumen ¿Son los aceites de oliva más inestables que los aceites vegetales al calentarlos? Un estudio comparativo La demanda de alimentos saludables es grande y los aceites de oliva están ganando atención. Todavía, no hay consenso sobre las mejores formas de utilizarlo en la cocina. El objetivo de este estudio fue evaluar los posibles cambios físicos y químicos derivados del calentamiento de los aceites de oliva en comparación con otros aceites vegetales. Muestras de aceite de oliva virgen extra (AOE) o refinado de tipo único (AOU); aceite de canola (OC) y aceite de soja (OS) fueron seleccionados considerando las marcas más buscadas por la población. Estos fueron calentados a 40, 70, 120 y 180 ° C y analizados para rancificación hidrolítica (índice de acidez) y oxidativa (malondialdehído - MDA). Los resultados mostraron que el calentamiento puede alterar la disponibilidad de ácidos grasos libres en AOE y AOU (reducción de aproximadamente 30% en el índice de acidez en relación a la temperatura ambiente) en comparación con OC y OS. No se observaron cambios en este parámetro para los aceites. Para los niveles de MDA, se observó que tanto AOE como AOU son menos susceptibles a la termoxidación cuando se calientan, en comparación con las muestras de OC / OS, que mostraron tasas estadísticamente más altas. Cuando se compararon juntos, se observó el siguiente comportamiento para los niveles de acidez (AOE = AOU> OC = OS) y MDA (OS> OC> AOU = AOE). Los datos obtenidos en el presente estudio indican una mayor aplicabilidad de los aceites de oliva en preparaciones calentadas, sin embargo, son necesarios futuros estudios para comprender mejor las reacciones químicas involucradas en sus procesos de termoprotección. Palabras clave: Ácidos grasos; estabilidad; rancificación; antioxidantes.

Silica-Containing Hybrid Nanocomposite "Melting Gels"

2014 ◽  
Vol 783-786 ◽  
pp. 1432-1437 ◽  
Author(s):  
Lisa C. Klein ◽  
B. McClarren ◽  
Andrei Jitianu
Keyword(s):  
Dielectric Properties ◽  
Chemical Reactions ◽  
Room Temperature ◽  
Sol Gel ◽  
Hybrid Nanocomposite ◽  
Wide Range ◽  
Melting Gels ◽  
Sol Gel Process ◽  
Inorganic Nanocomposites ◽  
Inorganic Components

Hybrid organic-inorganic nanocomposites can be prepared by the sol-gel process. An attribute of the sol-gel process is that organic and inorganic components can be linked together on the nanoscale through chemical reactions at room temperature. Functionalized siloxanes can be mixed and reacted to form nanocomposites with a wide range of mechanical, optical and dielectric properties.

scholarly journals Room-Temperature Synthesis of Ni and Pt-Co Alloy Nanoparticles Using a Microreactor

2021 ◽  
Vol 3 ◽  
Author(s):  
Satoshi Watanabe ◽  
Tomohiro Koshiyama ◽  
Takeshi Watanabe ◽  
Minoru T. Miyahara
Keyword(s):  
Chemical Reactions ◽  
Room Temperature ◽  
Small Degree ◽  
Potential Productivity ◽  
Synthetic Process ◽  
Precise Control ◽  
Batch Type ◽  
Bimetallic System ◽  
Materials Used ◽  
Average Size

Metal nanoparticles (NPs) are key materials used in a broad range of industries. Among the various synthetic routes of NPs, liquid-phase chemical reactions are promising because of their versatility in reaction conditions as well as their potential productivity. However, because the synthesis of NPs involves not only chemical reactions but also nucleation and growth processes, which are typically higher-order reactions in terms of the concentration, a small degree of nonuniformity in the concentration during mixing of reaction solutions can easily result in a wide size distribution of the resultant particles. A typical solution to this problem is to slow the rate of reactions compared with that of mixing; however, as a result, the synthetic processes often require long reaction periods and complex procedures. In this study, we applied a microreactor with excellent mixing performance to NP synthesis to simplify and intensify the processes. We synthesized nickel and platinum-cobalt alloy NPs as model materials. For the Ni NP synthesis, we demonstrated that the quick mixing provided by the microreactor enabled the precise control of the residence time, and consequently, monodispersed Ni NPs with an average size of 3.8 nm were synthesized. For the Pt-Co bimetallic system, the microreactor successfully produced Pt-Co alloy NPs, while batch-type synthesis with weaker mixing intensity resulted in a bimodal mixture of larger Pt NPs and smaller Co NPs. For both Ni and Pt-Co, monodispersed NPs were synthesized by simply mixing the reaction solutions in the microreactor at room temperature. These results demonstrate that the mixing process plays a key role in NP synthesis, and application of a microreactor enables the establishment of a facile and robust synthetic process.

ChemInform Abstract: Room Temperature Molten Salts: Neoteric “Green” Solvents for Chemical Reactions and Processes

ChemInform ◽  
2001 ◽  
Vol 32 (6) ◽  
pp. no-no
Author(s):  
Jairton Dupont ◽  
Crestina S. Consorti ◽  
John Spencer
Keyword(s):  
Chemical Reactions ◽  
Molten Salts ◽  
Room Temperature ◽  
Green Solvents
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