Reactions of Alkyl Halides in Fused Salt Media

1971 ◽  
Vol 49 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. A. Bailey ◽  
S. F. Prest
Keyword(s):  
Organic Molecules ◽  
Product Distribution ◽  
Exchange Reactions ◽  
Cyclization Reactions ◽  
Composition Effects ◽  
Carbonium Ion ◽  
Product Distributions ◽  
Halide Exchange ◽  
Melt Composition ◽  
Acid Character

Passage of C1 to C5 haloalkanes through SnCl2–KCl melts results in halide exchange reactions, alkene formation, and rearrangement (including cyclization) reactions of the organic molecules. Relative reactivities, product distributions and melt composition effects are consistent with a carbonium ion mechanism in which the melt functions as a halide ion acceptor. Some control of product distribution by choice of Lewis acid character of the melt seems possible.

scholarly journals Effect of NO<sub><i>x</i></sub> on 1,3,5-trimethylbenzene (TMB) oxidation product distribution and particle formation

2019 ◽  
Vol 19 (23) ◽  
pp. 15073-15086 ◽  
Author(s):  
Epameinondas Tsiligiannis ◽  
Julia Hammes ◽  
Christian Mark Salvador ◽  
Thomas F. Mentel ◽  
Mattias Hallquist
Keyword(s):  
Urban Areas ◽  
Organic Molecules ◽  
Flow Reactor ◽  
Organic Aerosol ◽  
Product Distribution ◽  
Particle Formation ◽  
Product Distributions ◽  
Tropospheric Aerosol ◽  
Volatile Organic ◽  
Free Environment

Abstract. Secondary organic aerosol (SOA) represents a significant fraction of the tropospheric aerosol and its precursors are volatile organic compounds (VOCs). Anthropogenic VOCs (AVOC) dominate the VOC budget in many urban areas with 1,3,5-trimethylbenzene (TMB) being among the most reactive aromatic AVOCs. TMB formed highly oxygenated organic molecules (HOMs) in an NOx-free environment, which could contribute to new particle formation (NPF) depending on oxidation conditions where elevated OH oxidation enhanced particle formation. The experiments were performed in an oxidation flow reactor, the Go:PAM unit, under controlled OH oxidation conditions. By addition of NOx to the system we investigated the effect of NOx on particle formation and on the product distribution. We show that the formation of HOMs, and especially HOM accretion products, strongly varies with NOx conditions. We observe a suppression of HOM and particle formation with increasing NOx/ΔTMB ratio and an increase in the formation of organonitrates (ONs) mostly at the expense of HOM accretion products. We propose reaction mechanisms and pathways that explain the formation and observed product distributions with respect to oxidation conditions. We hypothesise that, based on our findings from TMB oxidation studies, aromatic AVOCs may not contribute significantly to NPF under typical NOx/AVOC conditions found in urban atmospheres.

scholarly journals Effect of NO<sub>x</sub> on 1,3,5-trimethylbenzene (TMB) oxidation product distribution and particle formation

2019 ◽  
Author(s):  
Julia Hammes ◽  
Epameinondas Tsiligiannis ◽  
Thomas F. Mentel ◽  
Mattias Hallquist
Keyword(s):  
Urban Areas ◽  
Organic Molecules ◽  
Flow Reactor ◽  
Organic Aerosol ◽  
Product Distribution ◽  
Particle Formation ◽  
Product Distributions ◽  
Tropospheric Aerosol ◽  
Volatile Organic ◽  
Free Environment

Abstract. Secondary organic aerosol (SOA) represents a significant fraction of the tropospheric aerosol and its precursors are volatile organic compounds (VOC). Anthropogenic VOCs (AVOC) dominate the VOC budget in many urban areas with 1,3,5-trimethylbenzene (TMB) being among the most reactive aromatic AVOCs. TMB formed highly oxygenated organic molecules (HOM) in NOx free environment, which could contribute to new particle formation (NPF) depending on oxidation conditions were elevated OH oxidation enhanced particle formation. The experiments were performed in an oxidation flow reactor, the Go : PAM unit, under controlled OH oxidation conditions. By addition of NOx to the system we investigated the effect of NOx on particle formation and on the product distribution. We show that the formation of HOM and especially HOM accretion products, strongly varies with NOx conditions. We observe a suppression of HOM and particle formation with increasing NOx / ΔTMB and an increase in the formation of organonitrates (ON) mostly at the expense of HOM accretion products. We propose reaction mechanisms/pathways that explain the formation and observed product distributions with respect to oxidation conditions. We hypothesize that, based on our findings from TMB oxidation studies, aromatic AVOCs may not contribute significantly to NPF under typical NOx / AVOC conditions found in urban atmospheres.

scholarly journals Highly oxygenated organic molecules produced by the oxidation of benzene and toluene in a wide range of OH exposure and NO<sub><i>x</i></sub> conditions

2021 ◽  
Vol 21 (15) ◽  
pp. 12005-12019
Author(s):  
Xi Cheng ◽  
Qi Chen ◽  
Yong Jie Li ◽  
Yan Zheng ◽  
Keren Liao ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Product Distribution ◽  
Experimental Conditions ◽  
Effective Lifetime ◽  
Product Distributions ◽  
Wide Range ◽  
Multifunctional Products ◽  
The Impact ◽  
Oxidation Of Benzene ◽  
Oxygenated Products

Abstract. Oxidation of aromatic volatile organic compounds (VOCs) leads to the formation of tropospheric ozone and secondary organic aerosol, for which gaseous oxygenated products are important intermediates. We show, herein, the experimental results of highly oxygenated organic molecules (HOMs) produced by the oxidation of benzene and toluene in a wide range of OH exposure and NOx conditions. The results suggest that multigeneration OH oxidation plays an important role in the product distribution, which likely proceeds more preferably via H subtraction than OH addition for early generation products from light aromatics. More oxygenated products present in our study than in previous flow tube studies, highlighting the impact of experimental conditions on product distributions. The formation of dimeric products, however, was suppressed and might be unfavorable under conditions of high OH exposure and low NOx in toluene oxidation. Under high-NOx conditions, nitrogen-containing multifunctional products are formed, while the formation of other HOMs is suppressed. Products containing two nitrogen atoms become more important as the NOx level increases, and the concentrations of these compounds depend significantly on NO2. The highly oxygenated nitrogen-containing products might be peroxyacyl nitrates, implying a prolonged effective lifetime of RO2 that facilitates regional pollution. Our results call for further investigation on the roles of high-NO2 conditions in the oxidation of aromatic VOCs.

scholarly journals Relative Rates of Bond Rotation and Ring Closure in the Photocycloaddition Intermediates from Fullerene-C60 and the Isomeric 2,4-Hexadienes

2019 ◽  
Author(s):  
Wendell Dilling
Keyword(s):  
Relative Rate ◽  
Product Distribution ◽  
Fullerene C60 ◽  
Ring Closure ◽  
Trans Conformation ◽  
Bond Rotation ◽  
Product Distributions

<p>Photocycloaddition of fullerene-C<sub>60 </sub>to the isomeric 2,4-hexadienesreported by Orfanopoulos and co-workers gave a series of 2 + 2 cycloadducts in which bond rotation had occurred in some products. Relative rates of bond rotation and ring closure in the biradical intermediates were calculated from the product distributions using equations developed by Bartlett and co-workers. These data are reinterpreted to show that the ratio of the rate of bond rotation in the intermediate to the rate of ring closure to the cyclobutane product is ~70 for the <i>trans</i>-1-propenyl intermediate formed in the initial cis conformation. Data are inconsistent for the analogous <i>cis</i>-1-propenyl intermediate. The relative rate for the <i>trans</i>-1-propenyl intermediate formed in the initial trans conformation is ~9. Accurate relative rate determinations are highly dependent on very accurate product distribution determinations.</p>

The mechanism of the pinacol-pinacone rearrangement. V. Carbon isotope effects

1957 ◽  
Vol 10 (1) ◽  
pp. 7 ◽  
Author(s):  
JF Duncan ◽  
KR Lynn
Keyword(s):  
High Temperature ◽  
Transition State ◽  
Carbon Isotope ◽  
Isotope Effects ◽  
Alternative Mechanism ◽  
Alternative Route ◽  
Temperature Reaction ◽  
Exchange Reactions ◽  
Carbonium Ion ◽  
High Temperature Reaction

The intermolecular isotope effects of methyl-labelled and alcoholic carbon-labelled pinacol converted to pinacone have been studied over a temperature range of 60-113.5 �C. Tests were made to establish the validity of the results by using two starting materials for synthesizing methyl-labelled pinacol, and several different methods of analysing the products. The isotope effects were determined by measurements made both on (i) pinacol and (ii) pinacone. The results above 80 �C can be interpreted in terms of the synartetic ion mechanism provided both the carbonium ion and the transition state are largely unhydrated, and both the formation of the carbonium ion and the methyl migration are slow steps. Below 60 �C an alternative mechanism is operative. Unless unsuspected exchange reactions are present, the results suggest that the transition state is not so greatly distorted from a simple ethane-type configuration as in the high temperature reaction. Results at intermediate temperatures indicate that the alternative route proceeds via a stable intermediate.

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