CATALYZED NITRATION OF AMINES: V. THE NITRATION OF ALIPHATIC DIALKYLGHLORAMINES

1948 ◽  
Vol 26b (3) ◽  
pp. 257-270 ◽  
Author(s):  
George F Wright ◽  
G. S. Myers
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Secondary Amines ◽  
Chain Reaction ◽  
Rate Controlling Step ◽  
By Products

It has been found that dialkylchloramines can be nitrated to dialkylnitramines either in nitric acid or, better, in a mixture of nitric acid and acetic anhydride. Electropositive chlorine also is formed during this nitration. This formation supports a postulate that chloride-catalyzed nitration of secondary amines proceeds via the chloramine as an intermediate. Since electropositive chlorine is regenerated, the catalyzed nitration can be considered as a self-sustaining chain reaction. Examination of the by-products resulting from nitration of chloramines indicates that chloramine nitration, and not chloramine formation, is the rate-controlling step in the catalyzed nitration.

NITROLYSIS OF HEXAMETHYLENETETRAMINE: VI. RECOMBINATION OF FRAGMENTS DURING HEXAMETHYLENETETRAMINE NITROLYSIS IN ACETIC ANHYDRIDE

1949 ◽  
Vol 27b (6) ◽  
pp. 520-544 ◽  
Author(s):  
E. Aristoff ◽  
J. A. Graham ◽  
R. H. Meen ◽  
G. S. Myers ◽  
G. F Wright
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Ammonium Nitrate ◽  
Degradation Products ◽  
Stepwise Synthesis ◽  
Alternative Hypotheses ◽  
Enhanced Yield ◽  
By Products

Alternative hypotheses can account for the yield of more than one equivalent of Cyclonite from hexamine when the Bachmann reagents, ammonium nitrate, nitric acid, and acetic anhydride are used. In the nitrolysis, evidence for a stepwise synthesis from unit fragments is presented as the enhanced yield when methylenedinitramine is added with paraform to ammonium nitrate and acetic anhydride according to the Schiessler–Ross method for Cyclonite synthesis. However, this evidence is discounted because the expected by-product, 1,5-diacetoxy-2,4-dinitro-2,4-diazapentane is not found. Alternatively it is believed that the Bachmann reaction is actually a combination of the direct nitrolysis of hexamine with nitric acid, concurrent with a resynthesis of hexamine from the fragments produced by the nitrolysis. On this basis all by-products from the hexamethylenetetramine nitrolysis must be accounted as degradation products of hexamethylenetetramine and not capable of synthesis from unit fragments like formaldehyde, ammonia, and acetic acid. No exception has been found; the addition of acylamides to the Bachmann reaction mixture increases the yield of two by-products, 1-acyl-3,5-dinitro-1,3,5-triazacyclohexane and 1-acyl-3,5,7-trinitro-1,3,5,7-tetrazacycloöctane. It has been shown that these can be formed only from degradation products of hexamethylenetetramine such as 1,5-diaceto-3,7-endomethylene-1,3,5,7-tetrazacycloöctane and acetaminomethylhexamethylenetetramine nitrate.

CATALYZED NITRATION OF AMINES: VIII. THE MEDIUM USED IN NITRATION OF SECONDARY ALIPHATIC AMINES

1948 ◽  
Vol 26b (3) ◽  
pp. 294-308 ◽  
Author(s):  
Thelma Connor ◽  
George F Wright ◽  
G. N. R. Smart
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Hydrogen Chloride ◽  
Zinc Chloride ◽  
Acetyl Chloride ◽  
Maximum Amount ◽  
Initial Formation ◽  
Reaction Systems ◽  
Elemental Chlorine ◽  
Rate Controlling Step

The reaction [Formula: see text] has been found to be reversible in acetic anhydride. Analysis for electropositive chlorine and for nitric acid in this reacting system indicates that consumption of NO3− and production of Cl+ passes through a maximum after which nitric acid is regenerated and electropositive chlorine disappears. This phenomenon has been interpreted as an initial formation of chlorine acetate (or other chlorine ester) which then decomposes to give elemental chlorine. The increased demand for hydrogen chloride then shifts the equilibrium toward regeneration of nitric acid. The reaction has been found to be second order in its kinetics, with an activation energy of about 8000 cal. It is probably not the rate-controlling step in the catalyzed nitration, except perhaps where such nitration is easy and efficient. When nitration is difficult the electropositive chlorine tends to accumulate. When it becomes elemental chlorine, it is ineffective for nitration catalysis and is destructive to the amine. The catalysts acetyl chloride and zinc chloride have been studied. Electropositive chlorine formation occurs at the same rate with acetyl chloride as with hydrogen chloride. Zinc chloride, on the other hand, has been found to generate the maximum amount of electropositive chlorine immediately. This indicates that zinc chloride would be a good catalyst for easily nitrated amines but less efficient for amines which react more slowly, since the chlorine acetate not consumed by chloramination would decompose to give the destructive elemental chlorine. No mono-, di-, or trichloroacetic acids, nor perchloric acid, could be detected in aged reaction systems initially hydrogen chloride – nitric acid – acetic anhydride.

CATALYZED NITRATION OF AMINES: III. THE EASE OF NITRATION AMONG ALIPHATIC SECONDARY AMINES

1948 ◽  
Vol 26b (1) ◽  
pp. 114-137 ◽  
Author(s):  
G. E. Dunn ◽  
J. C. MacKenzie ◽  
J. W. Suggitt ◽  
George F Wright ◽  
W. J. Chute ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Nitrous Acid ◽  
Active Form ◽  
Secondary Amines ◽  
Side Reactions ◽  
Aqua Regia ◽  
Nitryl Chloride ◽  
Alkyl Groups ◽  
Chloride Catalyst

A series of secondary amines, the proton-attracting ability of which had previously been determined, have been converted to their nitramines with nitric acid and acetic anhydride. The gradation in ease of nitration has been found to vary inversely with the proton-attracting ability of the amine. Nitration becomes so difficult at an amine strength corresponding to that of diethanolamine that nitric acid and acetic anhydride alone are ineffective; a chloride catalyst must be used. The amount of this catalyst must be increased as the proton-attracting ability of the amine becomes greater until a full equivalent is required for adequate yield from the strongest amine in the series, diisopropylamine. As the nitration in the series becomes more difficult, side reactions become apparent such as nitrosation, acetylation, and fission of the secondary amine to primary amine and aldehyde. The extent of nitrosation is dependent on the concentration of catalyst, although nitrosation is not catalyzed by presence of chloride. This implies that hydrogen chloride generates nitrous acid in the reaction mixture. Acetylation is independent of presence or concentration of catalyst, but it does not occur during the formation of dicyclohexylnitramine or diisopropylnitramine. This is thought to be owing to steric hindrance from the secondary alkyl groups in these amines. Since nitracidium perchlorate has been found to be ineffective as a catalyst for this nitration, it is doubtful that nitryl chloride is the active form of the catalyst except in so far as it exists in the form of chlorine nitrite. Evidence has accumulated to show that electropositive chlorine is the effective catalyst, and that it is formed by a modification of the aqua regia reaction.

scholarly journals PRIMEval: Optimization and screening of multiplex oligonucleotide assays

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Rick Conzemius ◽  
Michaela Hendling ◽  
Stephan Pabinger ◽  
Ivan Barišić
Keyword(s):  
In Silico ◽  
Multiplex Polymerase Chain Reaction ◽  
Data Sets ◽  
Use Case ◽  
Chain Reaction ◽  
Experimental Conditions ◽  
Oligonucleotide Hybridization ◽  
Polymerase Chain ◽  
Derived Data ◽  
By Products

AbstractThe development of multiplex polymerase chain reaction and microarray assays is challenging due to primer dimer formation, unspecific hybridization events, the generation of unspecific by-products, primer depletion, and thus lower amplification efficiencies. We have developed a software workflow with three underlying algorithms that differ in their use case and specificity, allowing the complete in silico evaluation of such assays on user-derived data sets. We experimentally evaluated the method for the prediction of oligonucleotide hybridization events including resulting products and probes, self-dimers, cross-dimers and hairpins at different experimental conditions. The developed method allows explaining the observed artefacts through in silico WGS data and thermodynamic predictions. PRIMEval is available publicly at https://primeval.ait.ac.at.

Selective Nitroxylation of Adamantane Derivatives in the System Nitric Acid–Acetic Anhydride

2020 ◽  
Vol 56 (9) ◽  
pp. 1532-1539
Author(s):  
Yu. N. Klimochkin ◽  
E. A. Ivleva ◽  
I. K. Moiseev
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Adamantane Derivatives

Addition Reactions in the Nitration of Some Polycyclic Aromatic Compounds

1972 ◽  
Vol 50 (20) ◽  
pp. 3367-3372 ◽  
Author(s):  
A. Fischer ◽  
D. R. A. Leonard
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Nitro Group ◽  
Aromatic Compounds ◽  
Addition Reaction ◽  
Polycyclic Aromatic Compounds ◽  
Addition Reactions ◽  
Polycyclic Aromatic ◽  
Acetyl Nitrate

Reaction of 3-oxo-1,2,3,7,8,9,10,10a-octahydrocyclohepta[de]naphthalene with nitric acid in acetic anhydride gives two stereoisomeric 4-acetoxy-6a-nitro-3-oxo-1,2,3,4,6a,7,8,9,10,10a-decahydrocyclohepta[de]-naphthalenes as well as the expected nitro substitution products. Formation of these adducts from a substrate containing a meta-directing deactivating substituent shows that the 1,4-addition reaction of acetyl nitrate is more general than previously suspected. 1,4-Acetyl nitrate adducts are also formed from tetralin, benzsuberane, 5,6,7,8-tetrahydrocyclohepta[fg]acenaphthene, and 1,2,3,4,7,8,9,10-octahydrodicyclohepta[de,ij]naphthalene. Decomposition of the last two adducts gives in each case a product with the nitro group substituted into the alicyclic ring.

scholarly journals Nitrosamine formation from the oxidation of secondary amines

2011 ◽  
Vol 11 (3) ◽  
pp. 259-265 ◽  
Author(s):  
Tom Bond ◽  
Michael R. Templeton
Keyword(s):  
Water Treatment ◽  
Uv Irradiation ◽  
Secondary Amines ◽  
Research Activity ◽  
And Control ◽  
By Products

The nitrosamines are potent carcinogens which can be formed as by-products during water treatment. Much recent research activity has been focussed upon the formation, occurrence and control of N-nitrosodimethylamine (NDMA) in particular. In this study, seven secondary amines were oxidised by chlorine, ozone, and UV-irradiation, with and without post-chloramination, to quantify the effect on the formation of seven nitrosamines, including NDMA. While the yields of nitrosamines ranged from 0.01% for N-nitroso-di-n-butylamine (NDBA) to 2.01% for N-nitrosopyrrolidine (NPYR) under conditions of excess monochloramine at pH 7, yields from other oxidants were zero. Pre-oxidation with chlorine reduced nitrosamine formation by up to 83% compared with chloramination alone. This illustrates that in situations where secondary amines are key precursors, chlorine addition before ammonia during chloramination can be expected to limit nitrosamine formation. UV irradiation at 40 mJ cm−2 had little observed impact. Ozonation enhanced NDMA and N-nitrosomethylethylamine (NMEA) formation by subsequent chloramination to 7.48% and 10.15%, respectively.

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