Efficient synthesis of fluoro-containing liquid crystal materials via Pd-catalysed room temperature aerobic Suzuki reactions in aqueous media

2014 ◽  
Vol 42 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Wenna Xie ◽  
Daoan Xiao ◽  
Yongju Wen ◽  
Jiamin Li ◽  
Lasheng Wang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Room Temperature ◽  
Aqueous Media ◽  
Efficient Synthesis ◽  
Suzuki Reactions ◽  
Liquid Crystal Materials

Efficient synthesis of pyrido[2,3-d]pyrimidine-7-carboxylic acids catalyzed by a TiO2/SiO2 nanocomposite in aqueous media at room temperature

2018 ◽  
Vol 73 (9) ◽  
pp. 641-645 ◽  
Author(s):  
Sepehr Sadegh-Samiei ◽  
Shahrzad Abdolmohammadi
Keyword(s):  
Heterogeneous Catalyst ◽  
Carboxylic Acids ◽  
Room Temperature ◽  
Aqueous Media ◽  
Reaction Times ◽  
Molar Ratio ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
Moderate Reaction ◽  
Recyclable Heterogeneous Catalyst

AbstractA novel and efficient synthesis of eight 5-aryl-1,3-dimethyl-2,4-dioxo-1,2,3,4,5,8-hexahydropyrido[2,3-d]pyrimidine-7-carboxylic acids using a TiO2/SiO2 nanocomposite with a molar ratio of 1:1 as a recyclable heterogeneous catalyst is described. The desired products, five of which are new, are formed in short reaction times (2–3 h) with high to excellent yields (94%–98%) under very moderate reaction conditions (room temperature, aqueous media).

ChemInform Abstract: Room Temperature Suzuki Reactions in Aqueous Media under Air by Palladium(II) Complexes with Pyrazole Derived Ligands.

ChemInform ◽  
2010 ◽  
Vol 41 (33) ◽  
pp. no-no
Author(s):  
Kai Xu ◽  
Xin-Qi Hao ◽  
Jun-Fang Gong ◽  
Mao-Ping Song ◽  
Yang-Jie Wu
Keyword(s):  
Room Temperature ◽  
Aqueous Media ◽  
Suzuki Reactions

Room Temperature Suzuki Reactions in Aqueous Media under Air by Palladium(II) Complexes with Pyrazole Derived Ligands

2010 ◽  
Vol 63 (2) ◽  
pp. 315 ◽  
Author(s):  
Kai Xu ◽  
Xin-Qi Hao ◽  
Jun-Fang Gong ◽  
Mao-Ping Song ◽  
Yang-Jie Wu
Keyword(s):  
Aqueous Solution ◽  
13C Nmr ◽  
Room Temperature ◽  
Phenylboronic Acid ◽  
Aqueous Media ◽  
Palladium Complexes ◽  
Coupling Reactions ◽  
X Ray ◽  
Suzuki Reactions ◽  
Aryl Bromides

Two new palladium complexes with pyrazole derived ligands 2a–2b have been easily prepared and well characterized by elemental analysis, 1H NMR, 13C NMR, and IR spectra. Their detailed structures are determined by a single-crystal X-ray analysis of 2a. The two compounds were successfully applied to the Suzuki coupling reactions of aryl bromides with phenylboronic acid, in aqueous solution at room temperature under air, giving the desired coupled products in good to excellent yields with catalyst loadings as low as 0.01–0.05 mol-%.

Introduction of Succinimide as A Green and Sustainable Organo-Catalyst for the Synthesis of Arylidene Malononitrile and Tetrahydrobenzo[b]pyran Derivatives.

2020 ◽  
Vol 23 ◽  
Author(s):  
Fariba Hassanzadeh ◽  
Farhad Shirini ◽  
Manouchehr Mamaghani ◽  
Nader Daneshvar
Keyword(s):  
Aromatic Aldehyde ◽  
Room Temperature ◽  
Aqueous Media ◽  
Aromatic Aldehydes ◽  
Distilled Water ◽  
Efficient Synthesis ◽  
Purification Step ◽  
Solid Product ◽  
Obvious Effect ◽  
Pure Product

Aim and Objective: In this work, we tried to introduce a nontoxic and stable organic compound named succinimide as a green and efficient organo-catalyst for the promotion of the synthesis of arylidene malononitrile and tetrahydrobenzo[b]pyran derivatives. Using this method led to a clean procedure to achieve these types of bioactive compounds without a specific purification step. The rate and yield of the reactions were excellent and also succinimide showed acceptable reusability as the catalyst. Materials and Methods: In a 25 mL round-bottom flask, [A: a mixture of aromatic aldehyde (1 mmol), malononitrile (1.1 mmol) and B: a mixture of aromatic aldehyde (1.0 mmol), malononitrile (1.1 mmol)] and succinimide (0.2 mmol) in H2O/ EtOH [5 mL (1:1)] was stirred at 80 ˚C for an appropriate time. After completion of the reaction, which was monitored by TLC [n-hexane-EtOAc (7:3)], the mixture was cooled to room temperature and the solid product was filtered, washed several times with cold distilled water to obtain the corresponding pure product. Results: After the optimization of the conditions and amount of the catalyst, a series of aromatic aldehydes containing eitherelectron-donating or electron-withdrawing substituents were successfully used for both of the reactions. The reactions rates and yields under the selected conditions were excellent. The nature and electronic properties of the substituents had no obvious effect on the rate and yield of the reaction. Meanwhile, the catalyst showed acceptable reusability for these two reactions. Conclusion: In this work, we have introduced Succinimide as a green and safe organo-catalyst for the efficient synthesis arylidene malononitrile and tetrahydrobenzo[b]pyran derivatives. The results showed that the catalyst had excellent efficiency in green aqueous media and also the reusability of the catalyst was good.

Temperature Dependence of the Self-Assembled Styrene Based Random Ionomers in Aqueous Solution

2003 ◽  
Vol 775 ◽  
Author(s):  
Sung-Hwa Oh ◽  
Ju-Myung Song ◽  
Joon-Seop Kim ◽  
Hyang-Rim Oh ◽  
Jeong-A Yu
Keyword(s):  
Partition Coefficients ◽  
Room Temperature ◽  
Aqueous Media ◽  
The Self ◽  
Spectroscopic Methods ◽  
Ion Content ◽  
Repeat Units ◽  
Notable Effect ◽  
Order Of Magnitude ◽  
Experimental Errors

AbstractSolution behaviors of poly(styrene-co-sodium methacrylate) were studied by fluorescence spectroscopic methods using pyrene as a probe. The mol% of methacrylate was in the range 3.6–9.4. Water and N,N-dimethylforamide(DMF) mixture was used as a solvent (DMF/water = 0.2 mol %). The critical micelle (or aggregation) concentrations of ionomers and the partition coefficients of pyrene were obtained the temperature range 10–80°C. At room temperature, the values of CMCs (or CACs) were in the range 4.7 ×10-6 5.3 ×10-6 g/mL and we could not find any notable effect of the content of ionic repeat units within the experimental errors. Unlike CMCs, as the ion content increased, partitioning of pyrene between the hydrophobic aggregates and an aqueous media decreased from 1.5 ×105 to 9.4 ×104. As the temperature increased from 10 to 80 °C, the values of CMCs increased less than one order of magnitude. While, the partition coefficients of pyrene decreased one order of magnitude and the effect of the ion content became negligible.

Efficient synthesis of chromonylpyrano[c]coumarin, chromonylbenzo[b]pyran, and pyrano[d]pyrimidine in aqueous media

2015 ◽  
Vol 12 (10) ◽  
pp. 1859-1865 ◽  
Author(s):  
Hamid Reza Bijanzadeh ◽  
Saber Mehrparvar ◽  
Saeed Balalaie
Keyword(s):  
Aqueous Media ◽  
Efficient Synthesis

Effects of Rotation on Heat Transfer for a Single Row Jet Impingement Array With Crossflow

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Justin A. Lamont ◽  
Srinath V. Ekkad ◽  
Mary Anne Alvin
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Rotation Number ◽  
Coriolis Force ◽  
Room Temperature ◽  
Turbine Blades ◽  
Target Surface ◽  
Channel Height ◽  
Potential Core ◽  
Single Row

The effects of the Coriolis force are investigated in rotating internal serpentine coolant channels in turbine blades. For complex flow in rotating channels, detailed measurements of the heat transfer over the channel surface will greatly enhance the blade designers’ ability to predict hot spots so coolant may be distributed more effectively. The present study uses a novel transient liquid crystal technique to measure heat transfer in a rotating, radially outward channel with impingement jets. A simple case with a single row of constant pitch impinging jets with the crossflow effect is presented to demonstrate the novel liquid crystal technique and document the baseline effects for this type of geometry. The present study examines the differences in heat transfer distributions due to variations in jet Rotation number, Roj, and jet orifice-to-target surface distance (H/dj = 1,2, and 3). Colder air, below room temperature, is passed through a room temperature test section to cause a color change in the liquid crystals. This ensures that buoyancy is acting in a similar direction as in actual turbine blades where walls are hotter than the coolant fluid. Three parameters were controlled in the testing: jet coolant-to-wall temperature ratio, average jet Reynolds number, Rej, and average jet Rotation number, Roj. Results show, such as serpentine channels, the trailing side experiences an increase in heat transfer and the leading side experiences a decrease for all jet channel height-to-jet diameter ratios (H/dj). At a jet channel height-to-jet diameter ratio of 1, the crossflow from upstream spent jets greatly affects impingement heat transfer behavior in the channel. For H/dj = 2 and 3, the effects of the crossflow are not as prevalent as H/dj = 1: however, it still plays a detrimental role. The stationary case shows that heat transfer increases with higher H/dj values, so that H/dj = 3 has the highest results of the three examined. However, during rotation the H/dj = 2 case shows the highest heat transfer values for both the leading and trailing sides. The Coriolis force may have a considerable effect on the developing length of the potential core, affecting the resulting heat transfer on the target surface.

Sign in / Sign up

Export Citation Format

Share Document