Epoxidation
Mostrando 1-12 de 128 artigos, teses e dissertações.
-
1. Easy Epoxidation of Monoterpenes from Common Starting Materials
Epoxidation of monoterpenes, α-pinene, β-pinene, limonene, α-terpinene, and (R)-carvone was carried out by the in situ production of a peroxyacid rather than direct addition of such an expensive and difficult to handle chemical. Previous reports showed use of metal catalysts with high yields, while methodologies without catalysts at high temperature showe
J. Braz. Chem. Soc.. Publicado em: 2020-05
-
2. Chiral Amino and Imino-Alcohols Based on (R)-Limonene
Derivatives of the natural occurring and inexpensive terpene (R) -limonene were synthetized and completely characterized. Starting from internal olefin epoxidation, followed by epoxide opening with sodium azide and azide reduction with LiAlH4, two chiral amino-alcohols were obtained. The amino-alcohols were reacted with three different aldehydes, generating
J. Braz. Chem. Soc.. Publicado em: 2020-03
-
3. EPOXIDATION OF JATROPHA METHYL ESTERS VIA ACIDIC ION EXCHANGE RESIN: OPTIMIZATION AND CHARACTERIZATION
Abstract Plant oils and their derivatives have been vigorously exploited as alternatives for synthesis of epoxides due to depletion of petroleum resources. In this study, crude jatropha oil (CJO) was subjected to a transesterification process to form jatropha methyl esters (JME) using peroxyacetic acid generated in situ from hydrogen peroxide and acetic acid
Braz. J. Chem. Eng.. Publicado em: 30/09/2019
-
4. Alternative use of oily fractions of olive oil
Abstract Oily fractions of olive oil not suitable for human consumption used were: lamp oil (AL), olive pomace oil (OO) and clear oil lees (CB). Polyols were obtained by modifications of epoxidation with subsequent hydrolysis (ALH, OOH, CBH) and transesterification (ALHT, OOHT, CBHT) in order to favor, then, the polymerization reactions. The analysis of the
Polímeros. Publicado em: 18/03/2019
-
5. Synthesis of Spiro-Pyrrolidinyloxindoles by Oxidative Rearrangement of N-Acyltetrahydro-β-carbolines Using an Oxone/Aqueous Acetone Mixture
Spiro-pyrrolidinyl-2-oxindoles were prepared by the oxidative rearrangement of Na-acetyl-1,2,3,4-tetrahydro-β-carbolines (THBC) using dimethyldioxirane generated in situ. The Na-acetyl THBC substrates were obtained by Pictet-Spengler and acyl-Pictet-Spengler reactions of L-tryptophan methyl ester, followed by Na-acetylation. The stereoselectivity of the oxi
J. Braz. Chem. Soc.. Publicado em: 2019-01
-
6. Synergistic Interactions between Ti-OOH and (PO4[WO2(O2)]4)3- of HPW/Zn-Ti Hydrotalcites: Efficient Heterogeneous Catalysts for the Epoxidation of Fatty Acid Methyl Ester
A series of HPW/Zn-Ti layered double hydroxides (LDHs) were prepared by immobilizing phosphotungstic acid (HPW) on the Zn-Ti LDHs. Systematically characterizations were performed to elucidate their structure. These HPW/Zn-Ti LDHs hybrids were used as heterogeneous catalysts in the epoxidation of fatty acid methyl ester (FAMEs) with H2O2. The HPW/Zn-Ti LDHs s
J. Braz. Chem. Soc.. Publicado em: 2018-01
-
7. The Lubricity Analysis of Cutting Fluid Emulsions
The new generation of cutting fluids should have some characteristics, such as low toxicity and biodegradability. A bio-cutting fluid emulsion are an excellent option because they present those properties, as well as good mechanical performance. The present study aims to investigate the lubricity of O/W emulsions (cutting fluid emulsion), varying the concent
Mat. Res.. Publicado em: 2017
-
8. A INFLUÊNCIA DA LIGAÇÃO DE HIDROGÊNIO EM REAÇÕES QUÍMICAS: REAÇÃO DE PRILESCHAJEW
Theoretical analysis at the BHandHLYP/6-311++G(d,p) level of theory with the support of QTAIM calculations was used to reinvestigate the structure of an intermolecular system formed between ethylene oxide (C2H4O) and formic acid (HCO2H) after the epoxidation known as the Prileschajew reaction. Geometric and infrared vibration results revealed that HO2CH form
Quím. Nova. Publicado em: 2015-01
-
9. Study of oxide nanoparticles as additives for vegetable lubricants
Currently, vegetable oils have been studied as biolubricants in order to reach new environmental standards. Besides being non-renewable, mineral oils from petroleum bring consequences to the environment due to its low biodegradability. Thus, the aim of this work is to develop a biolubricant and to add oxide nanoparticles (ZnO and CuO) in order to improve abr
Mat. Res.. Publicado em: 2014-10
-
10. Cloisite 15Aº nanoclay as an effective PTC for the epoxidation of hydroxyl terminated polybutadiene (HTPB)
A simple method is reported for the epoxidation of hydroxyl-terminated polybutadiene (HTPB) by using in-situ generated dimethyl dioxirane (DMD) as an oxidant and Cloisite 15Aº nanoclay as a phase-transfer catalyst (PTC). In order to find the optimum reaction conditions, real time analyses of the products as well as epoxidation progress, followed by ¹HNMR a
Polímeros. Publicado em: 12/09/2014
-
11. Epoxidação do β-cariofileno com lipases imobilizadas em gel de ágar
The immobilization of enzymes and microorganisms on solid supports has been developed in recent years. These biocatalysts may be used in organic media allowing their storage and reuse, thus reducing costs of the process. Herein, lipases from various sources were immobilized in agar gel and used as catalysts in the chemo-enzymatic epoxidation of β-caryophyll
Quím. Nova. Publicado em: 2014-07
-
12. Obtenção de monômeros naturais através da epoxidação de limoneno / Limonene epoxidation studies in order to obtain natural monomers
Uma das olefinas de fontes renováveis de maior importância no Brasil é o Limoneno, terpeno que compõe cerca de 90% do óleo da casca da laranja. O Brasil é o maior produtor mundial de laranja, com uma produção, entre 2010-2011, de cerca de 15,33 milhões de toneladas do fruto, dos quais 89% da produção são destinadas à produção de suco, sendo a
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/04/2012