نتایج جستجو برای: brönsted acid
تعداد نتایج: 747496 فیلتر نتایج به سال:
The Brønsted acidic ionic liquid ([BMIm]HSO4) catalyzed three-component synthesis of 2H-indazolo[2,1-b]phthalazine-trione derivatives at room temperature. The integrity of the ionic liquid remains reasonably unchanged when it is separated from the reaction mixture by water extraction, as it can be recycled several times without any loss of activity in each of the title syntheses. The products a...
The Brönsted acidic ionic-liquid [HO(3)S(CH(2))(4)mim] HSO(4), a novel dual catalyst-solvent, has been successfully applied in simultaneous microwave-assisted extraction and hydrolysis for the determination of flavonol glycosides in Ginkgo foliage. The parameters, namely the [HO(3)S(CH(2))(4)mim]HSO(4) concentration, microwave-irradiation power, microwave-irradiation time, and solid-liquid rati...
گیاهان juniperus excelsa m.beib. ,juniperus communis l. و juniperus sabina l. از گونههای دارویی با ارزش و معطر متعلق به جنس سروکوهی و راسته مخروطیان میباشند که در ارتفاعات رشته کوه البرز پراکندگی دارند. هدف از این پژوهش، شناسایی و مقایسه اجزای تشکیل دهنده اسانس میوه ها و سرشاخههای هوایی این گیاهان میباشد. در این تحقیق میوه و سرشاخههای سه گونه فوق در مرداد سال 1390 از منطقه هزار جریب بهشهر...
The chemo-selective hydrogenolysis of secondary hydroxyls is an important reaction for the production biomass-derived ?,?-diols. This case 1,3-propanediol from glycerol. Supported Pt-WOx materials are effective catalysts this transformation, and their activity often related to tungsten surface density Brönsted acidity, although there discrepancies in regard. In work, a series Pt-WOx/?-Al2O3 wer...
The bacterial reaction center (RC) converts light into chemical energy through the reduction of an internal quinone molecule Q(B) to Q(B)H(2). In the native RC, proton transfer is coupled to electron transfer and is not rate-controlling. Consequently, proton transfer is not directly observable, and its rate was unknown. In this work, we present a method for making proton transfer rate-controlli...
The Brønsted acidic ionic liquid ([BMIm]HSO4) catalyzed three-component synthesis of 2H-indazolo[2,1-b]phthalazine-trione derivatives at room temperature. The integrity of the ionic liquid remains reasonably unchanged when it is separated from the reaction mixture by water extraction, as it can be recycled several times without any loss of activity in each of the title syntheses. The products a...
اهمیت مطالعه در خصوص گیاهان دارویی از آنجا حاصل می شود که، یک و یا بخش هایی از این گیاهان حاوی مواد ارزشمند دارویی، غذایی و بهداشتی است. سنتز هر یک از این مواد موثره، فرآیندی طولانی و هزینه بر است. در این تحقیق، روغن کنجد با استفاده از امواج التراسونیک استخراج و سپس با gc/ms شناسایی شد. استفاده از این امواج در استخراج ترکیبات مختلف از بافت های گیاهی راندمان عمل و سرعت فرآیند استخراج را افزایش...
Kinetic studies on the pyridinolysis of aryl dithiocyclopentanecarboxyaltes 2 were carried out at 60.0 C in acetonitrile. In the aminolysis of 2, the βX values were 0.5 0.8 with anilines, and there was no breakpoint. However, in the pyridinolysis of 2, biphasic Brönsted plots were obtained, with a change in slope from a large value (βX ≅ 0.7) to a small value (βX ≅ 0.4) at pKa = 5.2. This was a...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید