A new method for measuring reaction times for odour detection at iso-intensity: Comparison between an unpleasant and pleasant odour

2006 ◽  
Vol 87 (3) ◽  
pp. 500-505 ◽  
Author(s):  
Tim J.C. Jacob ◽  
Liwei Wang
Keyword(s):  
Reaction Times ◽  
New Method ◽  
Pleasant Odour

Iron-Catalyzed C3-Formylation of Indoles with Formaldehyde and Aqueous Ammonia under Air

Synlett ◽  
2017 ◽  
Vol 28 (19) ◽  
pp. 2670-2674 ◽  
Author(s):  
Jin-Ming Yang ◽  
Bu-Bing Zeng ◽  
Qing-Dong Wang ◽  
Bin Zhou ◽  
Dong Fang ◽  
...  
Keyword(s):  
Aqueous Ammonia ◽  
Reaction Times ◽  
New Method

An efficient iron-catalyzed C3-selective formylation of free (N–H) or N-substituted indoles was developed by employing formaldehyde and aqueous ammonia, with air as the oxidant. This new method gave 3-formylindoles in moderate to excellent yields with fairly short reaction times. Moreover, this procedure for catalytic formylation of indoles can be applied to gram-scale syntheses.

scholarly journals Facile and efficient synthesis of xanthenedione derivatives promoted by niobium pentachloride

2016 ◽  
Vol 70 (12) ◽  
Author(s):  
Willian H. dos Santos ◽  
Luiz C. Da Silva-Filho
Keyword(s):  
Reaction Times ◽  
Cost Effective ◽  
New Method ◽  
Efficient Synthesis ◽  
One Pot ◽  
Niobium Pentachloride

AbstractXanthenedione derivatives were synthesised in one-pot reactions between arylaldehyde derivatives and 1, 3-cyclohexanedione promoted by niobium pentachloride. This new method is simple, cost-effective, high-yielding with a good variety of substrates generality, and can be conducted within reasonable reaction times.

Investigation of the Determination of Volatile Isothiocyanates in Mustard Seed and Flour

1968 ◽  
Vol 51 (3) ◽  
pp. 633-636
Author(s):  
D D Rosebrook ◽  
J E Barney
Keyword(s):  
Reaction Times ◽  
Silver Sulfide ◽  
New Method ◽  
Mustard Seed ◽  
Ground Seed ◽  
Yellow Mustard ◽  
Aoac Method

Abstract A study of the variables in the AOAC and ASTA methods for determining volatile isothiocyanates in mustard flour and seed has led to development of a new method that is useful for both mustard flour and seed. The proposed method dispenses with the long reaction times and the digestion of the silver sulfide precipitate now required by the AOAC method. When mustard seed is analyzed, the ground seed is boiled in water for 3 min to solubilize the sinigrin, and yellow mustard flour is added as a source of enzyme. When mustard flour is analyzed, the boiling procedure is omitted Results are more reliable by the proposed method than by the AOAC or ASTA method and analysis can be completed in a single day.

scholarly journals Magnesium Borate Synthesis by Microwave Energy: A New Method

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Azmi Seyhun Kipcak ◽  
Emek Moroydor Derun ◽  
Sabriye Piskin
Keyword(s):  
Reaction Times ◽  
High Heat ◽  
New Method ◽  
X Ray Diffraction ◽  
Magnesium Borate ◽  
X Ray ◽  
Boron Minerals ◽  
Ft Ir ◽  
Borate Minerals

Magnesium borates are one of the major groups of boron minerals that have important properties such as high heat and corrosion resistances and high coefficients of elasticity. In this study, magnesium borate minerals are synthesized using boric acid and magnesium oxide with a new method of microwave, and the synthesized minerals are characterized by various analysis techniques. The results show that pure, “magnesium borate hydrate” minerals are obtained at the end of various steps. The characterization of the products is determined with the techniques of X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, and Scanning Electron Microscopy (SEM). Additionally, overall “magnesium borate hydrate” yields are calculated and found about 67% at 270 W, 8 minutes and 360 W, 3 minutes of reaction times, respectively.

A new method for determining nuclear reaction times

1983 ◽  
Vol 126 (1-2) ◽  
pp. 16-19 ◽  
Author(s):  
V.Ya. Chumanov ◽  
O.V. Chumanova ◽  
T.V. Grankina ◽  
G.P. Pokhil ◽  
A.F. Tulinov
Keyword(s):  
Nuclear Reaction ◽  
Reaction Times ◽  
New Method

scholarly journals Tandem reaction for the synthesis of bicyclic ortho-aminocarbonitrile derivatives using DMAPA as a cheap and efficient catalyst

2020 ◽  
Vol 2 (2) ◽  
pp. 145-151
Author(s):  
Lisha Wu ◽  
◽  
Shiqiang Yan ◽  
Yinta Li ◽  
◽  
...  
Keyword(s):  
Aromatic Aldehyde ◽  
Multicomponent Reaction ◽  
Reaction Times ◽  
Aromatic Aldehydes ◽  
Catalytic Amount ◽  
New Method ◽  
Tandem Reaction ◽  
One Pot ◽  
Efficient Catalyst ◽  
Simple Filtration

To develop a new method for the synthesis of bicyclic ortho-aminocarbonitrile derivatives. Reaction of aromatic aldehydes, cycloketones and malononitrile with catalytic amount of 3-(dimethylamino)- 1-propylamine (DMAPA) in ethanol via Knoevenagel-Michael cascades. The bicyclic ortho-aminocarbonitrile derivatives were obtained with good to excellent yields along with short reaction times. The universality, excellent yields, mild reaction and easy collection through simple filtration indicate the preparation of orthoaminocarbonitriles derivatives is an efficient and suitable protocol, which use one-pot multicomponent reaction of aromatic aldehyde, cycloketone, and 2 equiv. of malononitrile under the catalytic amount of DMAPA in ethanol.

scholarly journals H2SO4-Silica Catalyzed One-Pot and Efficient Synthesis of Dihydropyrimidinones Under Solvent-Free Conditions

2011 ◽  
Vol 8 (s1) ◽  
pp. S462-S466 ◽  
Author(s):  
Seied Ali Pourmousavi ◽  
Maryam Hasani
Keyword(s):  
Condensation Reaction ◽  
Biginelli Reaction ◽  
Reaction Times ◽  
Solvent Free ◽  
New Method ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Solvent Free Conditions ◽  
High Yields

H2SO4-Silica efficiently catalyzes the three-component condensation reaction of aldehydes, 1,3-dicarbonyl compounds and urea/thiourea under solvent free conditions to afford the corresponding dihydropyrimidinones and thio-derivatives in high yields. Compared to the classical Biginelli reaction conditions, this new method consistently has the advantage of giving good yields and requiring short reaction times.

scholarly journals Tetramethylguanidine-functionalized melamine as a multifunctional organocatalyst for the expeditious synthesis of 1,2,4-triazoloquinazolinones

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mahnoush Keshavarz ◽  
Mohammad G. Dekamin ◽  
Manouchehr Mamaghani ◽  
Mohammad Nikpassand
Keyword(s):  
Analytical Methods ◽  
Reaction Times ◽  
Practical Method ◽  
New Method ◽  
Small Decrease ◽  
Chromatographic Purification ◽  
Selective Conversion ◽  
Work Up ◽  
Benzaldehyde Derivatives

AbstractNovel nano-ordered 1,1,3,3-tetramethylguanidine-functionalized melamine (Melamine@TMG) organocatalyst was prepared and adequately identified by various techniques including FTIR, EDX, XRD and SEM spectroscopic or microscopic methods as well as TGA and DTG analytical methods. The Melamine@TMG, as an effective multifunctional organocatalyst, was found to promote smoothly the three-component synthesis of 1,2,4-triazoloquinazolinone derivatives using cyclic dimedone, 3-amino-1,2,4-triazole and different benzaldehyde derivatives in EtOH at 40 °C. This practical method afforded the desired products in high to excellent yields (86–99%) and short reaction times (10–25 min). The main advantages of this new method are the use of heterogeneous multifunctional nanocatalyst, simple work-up procedure with no need for chromatographic purification, highly selective conversion of substrates and recyclability of the catalyst, which could be used in five consecutive runs with only a small decrease in its activity.

A new detector for fully automatic peptide synthesis

1990 ◽  
Vol 18 (6) ◽  
pp. 1308-1310 ◽  
Author(s):  
JOHN E. FOX
Keyword(s):  
Peptide Synthesis ◽  
Reaction Times ◽  
New Method ◽  
Reaction Cell ◽  
Optimum Reaction ◽  
Fully Automatic ◽  
Difficult Sequences ◽  
Solidphase Peptide Synthesis

Summary A new method of monitoring the rate of reactions in solidphase peptide synthesis is described. A conductivity detector in the reaction cell (patent applied for) enables the deprotection, washing and subsequent coupling stages to be examined in detail. The half-lives of the reactions can be calculated and hence the optimum reaction times can be predicted. Difficult sequences are sensed and appropriate action taken completely automatically.

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