THE PREPARATION OF CHLORITE HOLOCELLULOSE

1952 ◽  
Vol 30 (9) ◽  
pp. 668-678 ◽  
Author(s):  
J. H. E. Herbst
Keyword(s):  
Absorption Spectra ◽  
Room Temperature ◽  
Black Spruce ◽  
Insoluble Fraction ◽  
Ultraviolet Absorption ◽  
Sodium Chlorite ◽  
White Birch

Mildly acid sodium chlorite solutions were allowed to act on white birch and black spruce sawdust at room temperature for various times; the insoluble fraction and the soluble nondialyzable fraction were isolated and weighed. If chlorite acts selectively on lignin the sum of these two fractions in time approaches true holocellulose. Chlorine and methoxyl determinations and examination of the ultraviolet absorption spectra showed that this was only approximately true. A small amount of carbohydrates was probably lost, and evidence was found for the existence of a chlorite-resistant lignin fragment in the soluble nondialyzable fraction.

Ultraviolet Absorption Spectra of Selected Unsaturated Carbonyl and β-Dicarbonyl Compounds at High Temperatures

1969 ◽  
Vol 23 (5) ◽  
pp. 532-535 ◽  
Author(s):  
W. W. Haskell ◽  
I. A. Read
Keyword(s):  
Gas Phase ◽  
Absorption Spectra ◽  
High Temperatures ◽  
Total Pressure ◽  
Room Temperature ◽  
Ultraviolet Absorption ◽  
Effect Of Temperature ◽  
Dicarbonyl Compounds

The gas-phase absorption spectra of 2-methylpent-2-ene-4-one, 2-methylpent-l-en-3-one, trans-pent-3-en-2-one, pent-l-en-3-one, 2-methylpent-2-enal, 4-methylpent-2-enal, methacrolein, acrolein, acetylacetone, and 4-methylpentan-3-onal have been determined at 525°C and at a total pressure of 28.5 atm. The effect of temperature on the absorption has been investigated and, for comparison, the absorption spectra have also been determined in cyclohexane solution at room temperature.

THE ULTRAVIOLET ABSORPTION SPECTRA OF METHYL-1,2-BENZANTHRACENES

1956 ◽  
Vol 34 (7) ◽  
pp. 888-905 ◽  
Author(s):  
C. Sandorfy ◽  
R. Norman Jones
Keyword(s):  
Fine Structure ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Electronic Excitation ◽  
Energy Levels ◽  
Ultraviolet Absorption ◽  
Methyl Derivatives ◽  
Overlapping Bands

The ultraviolet absorption spectra of 1,2-benzanthracene, all twelve mono-methyl derivatives, and six dimethyl derivatives have been measured (a) at room temperature in n-heptane solution, (b) at −100 °C. in n-pentane solution. An analysis of the band envelopes indicates that most of the absorption between 33,000 and 25,000 cm.−1 arises from two series of overlapping bands. The members of each series are spaced at intervals of approximately 1400 cm.−1. The spacing between the two band series and their relative intensities are dependent on the nature and position of the alkyl substituents. Absorption between 40,000 and 33,000 cm.−1 can be treated in a similar manner. Other fine structure is also observed. It is considered most probable that each of the overlapping series of bands is associated with a separate electronic excitation. The significance of these observations is considered in relation to the theoretical treatments of the energy levels of 1,2-benzanthracene as developed by Klevens and Platt and by Moffitt.

FAR ULTRAVIOLET ABSORPTION SPECTRA OF N3AND N2+GENERATED BY ELECTRONS IMPACTING GASEOUS N2

2013 ◽  
Vol 779 (1) ◽  
pp. 40 ◽  
Author(s):  
Yu-Jong Wu ◽  
Hui-Fen Chen ◽  
Shiang-Jiun Chuang ◽  
Tzu-Ping Huang
Keyword(s):  
Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Far Ultraviolet

scholarly journals ULTRAVIOLET ABSORPTION SPECTRA AT REDUCED TEMPERATURES

1950 ◽  
Vol 187 (1) ◽  
pp. 299-312
Author(s):  
R.L. Sinsheimer ◽  
J.F. Scott ◽  
J.R. Loofbourow
Keyword(s):  
Absorption Spectra ◽  
Ultraviolet Absorption

ULTRAVIOLET ABSORPTION SPECTRA AND ACIDITIES OF ISOMERIC THIATRIAZOLE AND TETRAZOLE DERIVATIVES

1959 ◽  
Vol 37 (3) ◽  
pp. 563-574 ◽  
Author(s):  
Eugene Lieber ◽  
J. Ramachandran ◽  
C. N. R. Rao ◽  
C. N. Pillai
Keyword(s):  
Absorption Spectra ◽  
Absorption Maximum ◽  
Dipole Moments ◽  
Ring System ◽  
Ultraviolet Absorption ◽  
Characteristic Absorption ◽  
Tetrazole Derivatives

The ultraviolet absorption spectra of 5-(substituted)amino-1,2,3,4-thiatriazoles and the corresponding isomeric 1-substituted-tetrazoline-5-thiones have been studied. The spectra and the dipole moments of the 5-(substituted)amino-1,2,3,4-thiatriazoles eliminate the possibility of meso-ionic structures for these compounds. The dipole moments of 5-amino-, 5-methylamino-, and 5-dimethylamino-1,2,3,4-thiatriazole were all high but approximately of the same value (5.77 to 5.84 D). This suggests that the amino thiatriazoles are best represented by conventional covalent structures with significant ionic resonance contributions. The thiatriazole ring system exhibits a characteristic absorption maximum at 250–255 mμ and an electron-withdrawing effect approximately equal to the tetrazolyl ring system. The tetrazolinethionolyl ring system is similarly electron-withdrawing. The relative acidities of the 1-substituted-tetrazoline-5-thiones and the 5-alkylmercaptotetrazoles have also been studied and the results support the observations made on the basis of their ultraviolet absorption spectra.

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