Azo pigments and their intermediates. A reinvestigation of the tetrazotization of 1,4-diaminoanthraquinone

1991 ◽  
Vol 69 (8) ◽  
pp. 1183-1188 ◽  
Author(s):  
Kock-Yee Law ◽  
Ihor W. Tarnawskyj ◽  
Samuel Kaplan
Keyword(s):  
Acetic Acid ◽  
Acetic Acid Solution ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Fluoboric Acid ◽  
Angle Spinning ◽  
C Nmr ◽  
Nitrosylsulfuric Acid ◽  
Brown Precipitate

The azotization of 1,4-diaminoanthraquinone (1) by n-amyl nitrite in glacial acetic was reinvestigated. The structure of a red-brown precipitate, which was previously identified as anthraquinone-1,4-tetrazonium dichloride (3) by Schaarschmidt, was found to be incorrect. In this work, we have identified the red-brown solid as 4-aminoanthraquinone-1-diazonium chloride (2), a diazotized product of 1. The yield of 2 was 80%. The tetrazonium dichloride 3 was actually formed in minute quantity and is soluble in acetic acid. The tetrazonium product of 1 can be isolated as tetrafluoroborate salt 4 in 3.4% yield by adding fluoboric acid into the acetic acid solution. The structure 4 was confirmed by IR and cross-polarization magic angle spinning13C NMR spectroscopy. Further investigations showed that 1 can be quantitatively tetrazotized by nitrosylsulfuric acid in 78% sulfuric acid. The tetrazonium product was isolated as 4 in 74% yield. Key words: 1,4-diaminoanthraquinone, diazotization, tetrazotization, azo pigments.

Carbon-13 CP/MAS NMR and DR-FTIR spectroscopic studies of sugarcane distillery waste

1998 ◽  
Vol 78 (1) ◽  
pp. 227-236 ◽  
Author(s):  
M. B. Benke ◽  
A. R. Mermut ◽  
B. Chatson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Organic Carbon ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Distillery Waste ◽  
Angle Spinning ◽  
Cp Mas Nmr ◽  
C Nmr

The application of a sugarcane distillery waste known as vinasse to agricultural land has become a common practice in Brazil. The vinasse samples used in this study were collected from several sugarcane distilleries in Northeastern Brazil. These samples were fractionated into dissolved organic carbon (DOC) and particulate organic carbon (POC) fractions. Unfractionated and fractionated vinasse were studied using 13C cross-polarization and magic-angle spinning nuclear magnetic resonance (CP/MAS NMR) spectroscopy as well as diffuse reflectance Fourier-transform infrared (DR-FTIR) spectroscopy. Approximately 79 to 92% of the total unfractionated vinasse dry matter was in the form of DOC fraction. O-alkyl C (42–53% of the total C) and carboxyl C (12–25% of the total C) comprised a significant portion of the 13C NMR spectra of the DOC fraction. The presence of carbohydrates and COOH/COO− was suggested by the DR-FTIR as well. Both 13C NMR and DR-FTIR spectra of this fraction were generally similar to the spectra of the fulvic acid (FA) fraction of soil and sewage sludge. The spectra of DOC differed from the FA fraction in that they showed smaller amounts of aromatic C and had an absence of amide group (bands at 1650 cm−1 and 1540 cm−1). In the POC fraction, O-alkyl (17–52% of the total C) and alkyl C (15–41% of the total C) were the major contributors. The peaks at 62 ppm, 72 ppm, 84 ppm and 105 ppm in the O-alkyl region indicate the presence of cellulose and/or hemicellulose. The alkyl group was comprised mainly of long-chain structures. The total N content in this fraction is ~3–7 times as much as in the DOC fraction. The presence of amino acids in the POC fraction was suggested by both 13C NMR and DR-FTIR spectra. Key words:13C cross-polarization and magic-angle spinning nuclear magnetic resonance, dissolved organic carbon, Fourier-transform infrared, particulate organic carbon, vinasse

13C CP/MAS nuclear magnetic resonance of crystalline methylxylopyranosides

1985 ◽  
Vol 63 (1) ◽  
pp. 270-273 ◽  
Author(s):  
Michael G. Taylor ◽  
Robert H. Marchessault ◽  
Serge Perez ◽  
Peter J. Stephenson ◽  
Colin A. Fyfe
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Asymmetric Unit ◽  
Angle Spinning ◽  
Detailed Nature ◽  
C Nmr

The 13C nmr spectra of solids, acquired using the Cross Polarization/Magic Angle Spinning (CP/MAS) technique, are very sensitive to the detailed nature of crystalline packing. These effects are illustrated in the CP/MAS spectra of the α and β anomers of methyl-D-xylopyranoside. In the spectrum of the α anomer, which crystallizes with two molecules per unit cell, individual spectra can be resolved for the two molecules in the asymmetric unit of this crystal.

A 13C and 15N nuclear magnetic resonance study of solid ammonium thiocyanate

1987 ◽  
Vol 65 (5) ◽  
pp. 941-946 ◽  
Author(s):  
Ross M. Dickson ◽  
Michael S. McKinnon ◽  
James F. Britten ◽  
Roderick E. Wasylishen
Keyword(s):  
Ammonium Thiocyanate ◽  
Nuclear Magnetic Resonance Study ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Chemical Shielding ◽  
X Ray ◽  
Shielding Constants ◽  
Angle Spinning ◽  
Good Agreement ◽  
C Nmr

The static 13C nmr powder pattern for solid ammonium thiocyanate is analyzed to obtain the 13C chemical shielding anisotropy, 321 ± 7 ppm, and the 13C–14N dipolar splitting, 1295 ± 25 Hz. Slow magic angle spinning 15N nmr experiments are analyzed to obtain a nitrogen chemical shielding anisotropy of 415 ± 15 ppm. The 13C–14N dipolar splitting leads to an effective C—N bond length of 1.19 ± 0.01 Å, in good agreement with the value of 1.176 Å reported from accurate X-ray and neutron crystallographic studies. In solid NH4NCS absolute values of the average shielding constants [Formula: see text] and ct[Formula: see text] are 52 and 34 ppm, respectively. Comparison of calculated and observed [Formula: see text] values indicates that intermolecular interactions decrease the 13C and 15N shielding constants by approximately 10 and 30 ppm, respectively.

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