scholarly journals Synthesis Of L-Menthyl Acetic by Esterification L-Menthol and Acetic Anhydride with Variation Of Time

Al-Kimia ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Novia Suryani ◽  
A Ghanaim Fasya ◽  
Rurini Retnowati ◽  
Akyunul Jannah
Keyword(s):  
Acetic Anhydride ◽  
Wave Number ◽  
Base Peak ◽  
Ester Product

l-menthyl acetic is an ester with specific aroma that synthesized by reaction of l-menthol and acetic anhydride and useful in fragrance industry. This paper reports influenced variation of time reaction toward ester product and characteristics l- menthyl acetic based on TLC, FTIR, GC and GC-MS. Reaction using l-menthol, acetic anhydride and catalyst H­2­SO­4­ 98 % in diethyl eter solvent at temperature 60 °C with variation of time reaction (45, 60, 75, 90, 105 minutes). The result of research is variation of time influence product with highest yield 88,43 % for 90 minutes. Monitoring TLC achived R­f­ = 0,82; analysis by FTIR achived specific wave number ester 1736,96 cm-1; analysis by GC achived t­r­ = 14,82 minutes and analysis by GC-MS achived t­r­ = 16,13 minutes with base peak m/z = 95.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

DETERMINATION OF ALDOSTERONE AND DEOXYCORTICOSTERONE IN PLASMA USING 3H-ACETIC ANHYDRIDE AND VAPOUR PHASE ACETYLATION

1969 ◽  
Vol 61 (1_Suppl) ◽  
pp. S12 ◽  
Author(s):  
V. H. T. James ◽  
A. E. Rippon ◽  
M. L. Arnold
Keyword(s):  
Acetic Anhydride ◽  
Vapour Phase

Flow resistivity, characteristic impedance and complex wave number assessment of coconut fiber with thin thickness samples.

2017 ◽  
Author(s):  
Key Fonseca de Lima ◽  
Nilson Barbieri ◽  
Fernando Jun Hattori Terashima ◽  
Vinicius Antonio Grossl ◽  
Nelson Legat Filho
Keyword(s):  
Characteristic Impedance ◽  
Wave Number ◽  
Coconut Fiber ◽  
Complex Wave ◽  
Flow Resistivity ◽  
Complex Wave Number

A Modified Wave-number Domain Algorithm for Missile-borne Squinted SAR Data Processing

2011 ◽  
Vol 33 (6) ◽  
pp. 1453-1458 ◽  
Author(s):  
Zhong-yuan Xiao ◽  
Hua-ping Xu ◽  
Chun-sheng Li
Keyword(s):  
Data Processing ◽  
Wave Number ◽  
Sar Data

Inversion of Wave-number Spectrum from Simulated Bistatic High-frequency Radar Data

2011 ◽  
Vol 33 (10) ◽  
pp. 2477-2482
Author(s):  
Huan He ◽  
Heng-yu Ke ◽  
Xian-rong Wan ◽  
Fang-zhi Geng
Keyword(s):  
High Frequency ◽  
Radar Data ◽  
Wave Number ◽  
High Frequency Radar

Characterization of Flood Waves by Rating Curves

1997 ◽  
Vol 28 (1) ◽  
pp. 51-64 ◽  
Author(s):  
S.K. Mishra ◽  
M.K. Jain ◽  
S.M. Seth
Keyword(s):  
Phase Difference ◽  
Central India ◽  
Wave Number ◽  
Wave Characteristics ◽  
Travel Wave ◽  
Frame Work ◽  
Rating Curves ◽  
Exact Relationship ◽  
Flood Waves

The flood waves are characterized within the frame-work of loop (or hysteresis) of rating curves. The National Weather Service's Dam Break Flood Forecasting Model is used to generate the flood waves in the downstream valley of the Bargi dam located in Central India. The quantified hystereses, η, of non-dimensional rating curves are related with the corresponding flood wave characteristics, viz., speed of travel, wave number, phase difference, and attenuation. The analysis has led to the development of an exact relationship between η and phase difference. Using the concept of wave zoning, the better performance of the hysteresis based criteria compared with the available criteria is verified using Convex and Muskingum-Cunge routing in the wave zones. η limits are specified for the applicability of these simplified routing models. Furthermore, the envisaged applications of the based analysis are introduced.

Influence of viscosity temperature dependence on the spectral characteristics of the thermoviscous liquids flow stability equation

2019 ◽  
Vol 14 (1) ◽  
pp. 52-58 ◽  
Author(s):  
A.D. Nizamova ◽  
V.N. Kireev ◽  
S.F. Urmancheev
Keyword(s):  
Reynolds Number ◽  
Spectral Characteristics ◽  
Wave Number ◽  
Critical Parameters ◽  
Fluid Viscosity ◽  
Flat Channel ◽  
Stability Equation ◽  
The Stability ◽  
Thermoviscous Fluid ◽  
Sommerfeld Equation

The flow of a viscous model fluid in a flat channel with a non-uniform temperature field is considered. The problem of the stability of a thermoviscous fluid is solved on the basis of the derived generalized Orr-Sommerfeld equation by the spectral decomposition method in Chebyshev polynomials. The effect of taking into account the linear and exponential dependences of the fluid viscosity on temperature on the spectral characteristics of the hydrodynamic stability equation for an incompressible fluid in a flat channel with given different wall temperatures is investigated. Analytically obtained profiles of the flow rate of a thermovisible fluid. The spectral pictures of the eigenvalues of the generalized Orr-Sommerfeld equation are constructed. It is shown that the structure of the spectra largely depends on the properties of the liquid, which are determined by the viscosity functional dependence index. It has been established that for small values of the thermoviscosity parameter the spectrum compares the spectrum for isothermal fluid flow, however, as it increases, the number of eigenvalues and their density increase, that is, there are more points at which the problem has a nontrivial solution. The stability of the flow of a thermoviscous fluid depends on the presence of an eigenvalue with a positive imaginary part among the entire set of eigenvalues found with fixed Reynolds number and wavenumber parameters. It is shown that with a fixed Reynolds number and a wave number with an increase in the thermoviscosity parameter, the flow becomes unstable. The spectral characteristics determine the structure of the eigenfunctions and the critical parameters of the flow of a thermally viscous fluid. The eigenfunctions constructed in the subsequent works show the behavior of transverse-velocity perturbations, their possible growth or decay over time.

Syntheses and Cytotoxicity Screening of some Novel 1,2,4-Triazine Derivatives against Liver Carcinoma Cell Lines

2020 ◽  
Vol 17 ◽  
Author(s):  
W. Abd El-Fattah
Keyword(s):  
Acetic Anhydride ◽  
Cell Lines ◽  
Carcinoma Cell ◽  
Aromatic Aldehydes ◽  
Liver Carcinoma ◽  
Anticancer Activities ◽  
Carcinoma Cell Lines ◽  
Elemental Analyses ◽  
Triazine Derivatives ◽  
C Nmr

: In this work, 1,2,4-triazine derivatives were synthesized and evaluated for anticancer activities. Series of 1,2,4-triazine derivatives (4a, b) were prepared via the reaction of N-benzoyl glycine (1) with aromatic aldehydes in presence of fused sodium acetate and acetic anhydride to give 1,3-oxazolinone derivatives (2a, b), followed by condensation with 1-(ethoxycarbonyl) hydrazine (3) in glacial acetic acid. Compounds (4a, b) then reacted with acetic anhydride, ethyl chloroacetate and 2,4-dinitrophenyl hydrazine yielded the corresponding to N-acetyl derivatives (5a, b), N-(ethoxycarbonyl) methyl derivative (6) and 1,2-disubstituted hydrazine (7), respectively. The structures of the 1,2,4-triazine derivatives were confirmed by IR, 1H, 13C NMR, MS and elemental analyses. Anticancer activity of some 1,2,4-triazine derivatives (4-7) have been investigated. The results revealed that compounds 4a (IC50= 2.7μM), 5a (IC50= 1.5μM), and 5b (IC50= 3.9μM) show promising inhibitory growth efficacy compared to a standard antitumor drug (IC50= 4.6μM). These three compounds can be considered as potential agents against human hepatocellular carcinoma cell lines (HepG-2).

Synthesis of conjugates of 1-(carboxymethyl)cytosine and 1-(5-O-carboxymethyl-β-D-arabinofuranosyl)cytosine with proteins

1979 ◽  
Vol 44 (10) ◽  
pp. 3023-3032 ◽  
Author(s):  
Helmut Pischel ◽  
Antonín Holý ◽  
Günther Wagner
Keyword(s):  
Human Serum Albumin ◽  
Acetic Anhydride ◽  
Serum Albumin ◽  
Human Serum ◽  
Activated Esters ◽  
Hydrolysis Of

1-(Carboxymethyl)cytosine (Ia), 1-(5-O-carboxymethyl-β-D-arabinofuranosyl)cytosine (IIa) and 5'-O-carboxylmethylcytidine (IIIa) were transformed by treatment with acetic anhydride and 4-dimethylaminopyridine to the peracetyl derivatives Ib-IIIb. These products reacted with p-nitrophenol in the presence of N, N'-dicyclohexylcarbodiimide to give the activated esters Ic-IIIc which on reaction with ammonia, dimethylamine or 2-aminoethanol afforded the corresponding carboxamides Id-IIId, IIe,f. Reactions of Ic and IIc with human serum albumin and bovine γ-globulin at pH 9.2, followed by hydrolysis of the N- or O-acetyl groups at pH 9.5, gave 50% up to 64% yields of the respective conjugates Ig, IIg and Ih, IIh.

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