scholarly journals Optical rotation dispersion of cholesteric-nematic mixture

2021 ◽  
Vol 2056 (1) ◽  
pp. 012030
Author(s):  
E N Vasilchikova ◽  
A D Dmitrieva ◽  
A V Kondakova ◽  
A D Kurilov ◽  
V V Usachev ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Spectroscopy ◽  
Optical Rotation ◽  
Specific Rotation ◽  
Low Concentration ◽  
Helical Pitch ◽  
Rotation Dispersion ◽  
Rotation Constant

Abstract The dispersion of the specific rotation constant of a cholesteric-nematic mixture of 5CB and Ch17 at a low concentration was studied by optical spectroscopy. The dispersion of the anisotropy of the refractive index as a function of the wavelength is studied, and the helical pitch of the cholesteric-nematic mixture is calculated.

scholarly journals Sensitivity of Aerosol Refractive Index Retrievals Using Optical Spectroscopy

2014 ◽  
Vol 48 (11) ◽  
pp. 1133-1144 ◽  
Author(s):  
Kyle J. Zarzana ◽  
Christopher D. Cappa ◽  
Margaret A. Tolbert
Keyword(s):  
Refractive Index ◽  
Optical Spectroscopy

scholarly journals NILAI TAMBAH MINYAK AKAR WANGI DENGAN PEMEKATAN KADAR VETIVEROL MENGGUNAKAN EKSTRAKSI CO2 FLUIDA SUPERKRITIK

2014 ◽  
Vol 16 (2) ◽  
pp. 76-81 ◽  
Author(s):  
Anny Sulaswatty ◽  
Egi Agustian
Keyword(s):  
Carbon Dioxide ◽  
Refractive Index ◽  
Specific Gravity ◽  
Supercritical Fluid Extraction ◽  
Supercritical Fluid ◽  
Flow Rate ◽  
Optical Rotation ◽  
Process Conditions ◽  
Fluid Extraction ◽  
Great Opportunity

Potensi Indonesia akan minyak akar wangi yang berorientasi ekspor dalam industri kosmetik, parfum, sabun, keperluan terapi, antiseptik, massage oil, farmasi dan pestisida memberikan peluang yang besar untuk memenuhi kebutuhan dunia. Guna nilai tambah minyak akar wangi dengan meningkatkan kadar vetiverol sebagai komponen utama, diaplikasikan teknologi ekstraksi fluida karbondioksida superkritik yang merupakan perpaduan ekstraksi, fraksinasi dan deodorisasi dengan didukung keunggulan karbondioksida sebagai pelarut yang inert, ramah lingkungan, mudah dipisahkan, dan berdaya larut tinggi.  Minyak akar wangi Garut (Java vetiver oil) sebagai bahan baku, mempunyai karakteristik  kadar vetiverol  39.03 %; Bobot jenis 0.9977; indeks bias 1.5247;  putaran optik +38.1; kelarutan dalam alkohol 95%  yaitu 1:1 jernih; bilangan asam 28.1; bilangan ester 24.6; bilangan ester setelah asetilasi 115.5; serta tidak mengandung minyak lemak dan  minyak keruing. Pemilihan kondisi proses guna menghasilkan kandungan vetiverol optimal dilakukan dengan memvariasikan laju alir gas CO2, tekanan dan suhu sebagai parameter penting dalam keberhasilan proses ekstraksi minyak akar wangi dengan fluida CO2 superkritik. Pemilihan laju alir konstan dan lebih stabil  diperoleh pada 5.5 liter/menit, sedangkan untuk variasi tekanan ekstraktor (1500, 1750, 2000 psi) dan suhu ekstraktor (40-50oC);  tekanan dan suhu separator  500 psi dan 25oC serta waktu proses selama lima jam dengan pengambilan ekstrak setiap jam. Tekanan dan suhu proses yang optimal diperoleh pada 1750 psi dan suhu 40oC  dengan  rafinat minyak akar wangi berkadar vetiverol  51.82 %,  bilangan ester 7.2 dan bilangan ester setelah asetilasi  172.4. Tingginya tekanan dan rendahnya suhu berpengaruh terhadap perolehan ekstrak; penurunan rafinat; peningkatan nilai  bobot jenis ekstrak dan rafinat; indeks bias ekstrak dan rafinat; putaran optik ekstrak dan rafinat; peningkatan viskositas ekstrak dan rafinat; peningkatan bilangan ester ekstrak, bilangan ester setelah asetilasi ekstrak, serta kandungan vetiverol.Kata Kunci: Minyak Akar Wangi, Vetiverol, Ekstraksi Fluida Superkritik Potential Indonesian vetiver oil export oriented industry of cosmetics, perfumes, soaps, therapeutic purposes, antiseptic, massage oil, pharmaceutical and pesticide presents a great opportunity to meet the needs of the world. In order to add value vetiver oil by increasing the levels vetiverol as the main component, was applied to carbon dioxide supercritical fluid extraction technology which is a combination of extraction, fractionation and deodorization with excellence supported carbon dioxide as an inert solvent, eco-friendly, easily separated, and the high solubility. Garut vetiver oil (Java vetiver oil) as raw material, has the characteristics vetiverol levels 39.03%, specific gravity of 0.9977; refractive index of 1.5247; optical rotation +38.1; solubility in alcohol 95% is a clear 1:1; acid number 28.1; ester number 24.6; ester number after acetylation 115.5; as well as fats and oils contain no oil keruing. The selection process conditions in order to produce optimal vetiverol content performed by varying the flow rate of CO2 gas, pressure and temperature as an important parameter in the success of vetiver oil extraction with supercritical CO2 fluid. The selection of a constant flow rate and more stable obtained at 5.5 liters / min, whereas for pressure variation extractor (1500-2000 psi) and extractor temperature (40-50oC); separator pressure and temperature of 500 psi and 25 °C as well as the processing time for five hours by taking extracts every hour. Pressure and temperature optimum process obtained at 1750 psi and a temperature of 40oC with rafinat vetiverol vetiver oil yield of 51.82%, ester number 7.2, and ester number after acetylation 172.4. The high pressure and low temperature affect the acquisition of the extract; rafinat decline; increase in the value of specific gravity and rafinat extracts; refractive index and rafinat extract; optical rotation and rafinat extract; increase in the viscosity of the extract and rafinat; increase in numbers ester extract, ester number after acetylation extracts, as well as the content vetiverol. Key word: Vetiver Oil, Vetiverol, Supercritical Fluid Extraction.

Rubescins F–H, new vilasinin-type limonoids from the leaves of Trichilia rubescens (Meliaceae)

2019 ◽  
Vol 74 (7-8) ◽  
pp. 175-182
Author(s):  
Armelle Tontsa Tsamo ◽  
Julio Issah Mawouma Pagna ◽  
Pamela Kemda Nangmo ◽  
Pierre Mkounga ◽  
Hartmut Laatsch ◽  
...  
Keyword(s):  
Ab Initio ◽  
Methylene Chloride ◽  
High Resolution Mass Spectrometry ◽  
Optical Rotation ◽  
Cyclopropane Ring ◽  
Dispersion Data ◽  
Rotation Dispersion ◽  
Oxetane Ring ◽  
Related Compounds ◽  
Potential Precursor

Abstract Three new limonoids, designated as rubescins F (1), G (2), and H (3), together with two known compounds of this type, TS1 (4) and trichirubine A (5), were isolated from methylene chloride/methanol extracts of Trichilia rubescens leaves. The structures of these compounds were elucidated based on 1D and 2D nuclear magnetic resonance (NMR) analysis and complemented by electrospray ionization high-resolution mass spectrometry results and by comparison to data of related compounds described in the literature and ab initio calculations. Rubescin F (1) is the first limonoid from Trichilia spp. with an oxetane ring between C-7 and C-14, which seems to be formed by the isomerization of TS1 (4). The γ-hydroxybutenolide rubescin G (2) is a potential precursor of trichirubine A (5), whereas rubescin H (3) is the first example of a triterpenoid with a single bond between C-7/C-14, forming a cyclopropane ring. The absolute configuration of these limonoids was derived from biosynthetic considerations and ab initio calculations of NMR and optical rotation dispersion data.

Multifunctional weak measurement system that can measure the refractive index and optical rotation of a solution

2019 ◽  
Vol 114 (18) ◽  
pp. 181901 ◽  
Author(s):  
Yang Xu ◽  
Lixuan Shi ◽  
Tian Guan ◽  
Suyi Zhong ◽  
Xuesi Zhou ◽  
...  
Keyword(s):  
Refractive Index ◽  
Measurement System ◽  
Optical Rotation ◽  
Weak Measurement

scholarly journals OPTICAL ROTATION AND HELICAL POLYPEPTIDE CHAIN CONFIGURATION IN COLLAGEN AND GELATIN

1955 ◽  
Vol 1 (3) ◽  
pp. 203-214 ◽  
Author(s):  
Carolyn Cohen
Keyword(s):  
Optical Activity ◽  
Optical Rotation ◽  
Specific Rotation ◽  
X Ray Diffraction ◽  
Citrate Buffer ◽  
Gelatin Films ◽  
Dispersion Data ◽  
Single Term ◽  
Native Collagen ◽  
Helical Configuration

The optical rotation phenomena exhibited by a citrate-extracted fraction of ichthyocol (from carp swim bladder), as well as by the parent gelatin derived therefrom, have been studied. Dispersion data for all cases follow a single-term Drude equation, but the variations with state are adequately expressed by simple reference to changes in [α]D as follows:— 1. The native collagen fraction, dispersed in 0.15 M citrate buffer at pH 3.7 in the cold (11°C.), yields a high negative specific rotation, [α]D, near –350°. 2. During equilibration at 40°C., which causes conversion to a monodisperse parent gelatin, the rotation drops to about –110°. 3. Gelation at 2°C. results in a partial regain of rotation to around –290°. This mutarotation is reversible, depending on temperature. 4. In the range 0.02 to 0.28 per cent the native ichthyocol and the warm gelatin solutions show little concentration dependence, but with the cold gelatin solutions the specific rotation increases with concentration. Gelatin films formed by cold evaporation yield high specific rotation (ca. –620°), but those formed by hot evaporation retain low optical activity. 5. Since this same collagen-gelatin system has been investigated physicochemically, it is possible to relate molecular changes to the observed variations in optical rotation. Conclusions are similar to those of Robinson (1953), who studied other gelatins: high negative rotation is believed related to a native collagen polypeptide configuration, herein specified as helical (from x-ray diffraction considerations) and destroyed by heating. The possible roles of intermolecular interactions and of prevalent pyrrolidine constituents in influencing the helical configuration and optical activity are discussed.

III.—The Optical Rotation and Cryoscopic Behaviour of Sugars dissolved in (a) Pormamide, (b) Water

1915 ◽  
Vol 35 ◽  
pp. 22-45
Author(s):  
John Edwin Mackenzie ◽  
Sudhamoy Ghosh
Keyword(s):  
Aqueous Solution ◽  
Optical Rotation ◽  
Specific Rotation ◽  
Initial Value ◽  
Other Substances

The optical rotation of a solution of sucrose in water was first measured by Biot (Mém., 1819, ii, 41) in 1819. He introduced the term “optical saccharimetry” for the method of estimation of sugar by measurement of its optical rotation.In 1846, Dubrunfaut (Ann. Chim. Phys., 1846, xviii, 99) observed that the specific rotation of a freshly prepared aqueous solution of glucose decreased from an initial value of about + 110° to a constant value of +52°. The initial value being approximately double the constant value, he called the phenomenon “bi-rotation.” This term proved unsuitable in the case of other substances where a similar change of rotation took place, the initial and final values being rarely in the proportion of 2: 1; hence the expression “multi-rotation” came into use.

Method for the accurate determination of specific rotation. Specific rotation of valine and leucine

1969 ◽  
Vol 47 (15) ◽  
pp. 2739-2746 ◽  
Author(s):  
J. C. MacDonald
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Optical Rotation ◽  
Accurate Determination ◽  
Computer Calculation ◽  
Specific Rotation ◽  
Best Fit

The optical rotation of various concentrations of L-valine and L-leucine, dissolved in glacial acetic acid, or 5 or 6 M HCl, was measured with a photoelectric polarimeter at the nominal wavelengths 589, 578, 546, 436, and 365 nm and temperatures of 20, 25, and 30 °C. The specific rotation for any one wavelength, solute, and solvent could be defined by the equation [α]λT = A(1 + D(T − 25)) + BC, where T is temperature in °C, C is concentration in grams of solute per 100 ml of solution, and A, B, and D are constants. The best fit values of the constants were determined by computer calculation and are listed. Constants are also given for calculating a specific rotation based on grams of solute per 100 g of solution.

Optical method for measuring optical rotation angle and refractive index of chiral solution

2007 ◽  
Vol 46 (33) ◽  
pp. 8134 ◽  
Author(s):  
Jiun-You Lin ◽  
Kun-Huang Chen ◽  
Jing-Heng Chen
Keyword(s):  
Refractive Index ◽  
Optical Method ◽  
Rotation Angle ◽  
Optical Rotation

PHYSICAL CONSTANTS AND ESTIMATION OF STEREOISOMERIC 2,3-BUTANEDIOLS

1951 ◽  
Vol 29 (10) ◽  
pp. 885-894 ◽  
Author(s):  
R. W. Watson ◽  
J. A. R. Coope ◽  
J. L. Barnwell
Keyword(s):  
Refractive Index ◽  
Pilot Plant ◽  
Experimental Error ◽  
Specific Rotation ◽  
Optically Active ◽  
Temperature Relation ◽  
Aerobacter Aerogenes ◽  
Physical Constants ◽  
Beet Molasses

The refractive index – temperature relation for optically active and racemic diols is linear, with [Formula: see text] from 25° to 40°C.: for the meso-isomer [Formula: see text] from 25° to 50°C. The specific rotation [Formula: see text]. Measurements of [Formula: see text] and [Formula: see text] in suitably purified mixtures of stereoisomers allow calculation of the percentage of each isomer present. Tests of the method on known mixtures of all three stereoisomers show an experimental error of ±3%. Analyses of five diol samples from pilot plant fermentations of beet molasses by Aerobacter aerogenes reveal 65–87% meso-, from 2 to 16% dextro-, and from 0 to 33% racemic 2,3-butanediol.

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