The energetics and kinetics of the CH3CHO + (CH3)2NH/CH3NH2 reactions catalyzed by a single water molecule in the atmosphere

2018 ◽  
Vol 1140 ◽  
pp. 7-13 ◽  
Author(s):  
Ze-Gang Dong ◽  
Fang Xu ◽  
Bo Long
2020 ◽  
Vol 22 (18) ◽  
pp. 10027-10042 ◽  
Author(s):  
Parandaman Arathala ◽  
Mark Katz ◽  
Rabi A. Musah

The reaction of thioformaldehyde with OH radical assisted by a single water molecule in the atmosphere is negligible.


2017 ◽  
Vol 121 (44) ◽  
pp. 8465-8473 ◽  
Author(s):  
Arathala Parandaman ◽  
Chanin B. Tangtartharakul ◽  
Manoj Kumar ◽  
Joseph S. Francisco ◽  
Amitabha Sinha

2019 ◽  
Vol 471 ◽  
pp. 658-663 ◽  
Author(s):  
Yue Zhang ◽  
Xinying Lu ◽  
Dongsheng Song ◽  
Songbai Liu

2015 ◽  
Vol 26 (2) ◽  
pp. 541-550
Author(s):  
Li Wang ◽  
Rui-Xia Song ◽  
Min-Si Xin ◽  
Yan Meng ◽  
Wei Feng ◽  
...  

Author(s):  
Bruce C. Bunker ◽  
William H. Casey

Water is one of the most complex fluids on Earth. Even after intense study, there are many aspects regarding the structure, properties, and chemistry of water that are not well understood. In this chapter, we highlight the attributes of water that dictate many of the reactions that take place between water and oxides. We start with a single water molecule and progress to water clusters, then finally to extended liquid and solid phases. This chapter provides a baseline for evaluating what happens when water encounters simple ions, soluble oxide complexes called hydrolysis products, and extended oxide phases. The primary phenomenon highlighted in this chapter is hydrogen bonding. Hydrogen bonding dominates the structure and properties of water and influences many water–oxide interactions. A single water molecule has eight valence electrons around a central oxygen anion. These electrons are contained in four sp3-hybridized molecular orbitals arranged as lobes that extend from the oxygen in a tetrahedral geometry. Each orbital is occupied by two electrons. Two of the lobes are bonded to protons; the other two lobes are referred to as lone pairs of electrons. The H–O–H bond angle of 104.5° is close to the tetrahedral angle of 109.5°. The O–H bond length in a single water molecule is 0.96 Ǻ. It is important to recognize that this bond length is really a measure of the electron density associated with the oxygen lone pair bonded to the proton. This is because a proton is so incredibly small (with an ionic radius of only 1.3·10−5 Ǻ) that it makes no contribution to the net bond length. The entire water molecule has a hard sphere diameter of 2.9 Ǻ, which is fairly typical for an oxygen anion. This means the unoccupied lone pairs are distended relative to the protonated lone pairs, extending out to roughly 1.9 Ǻ. The unequal distribution of charges introduces a dipole within the water molecule that facilitates electrostatic interactions with other molecules.


2010 ◽  
Vol 122 (29) ◽  
pp. 5018-5021 ◽  
Author(s):  
Yoshiyuki Matsuda ◽  
Ayako Yamada ◽  
Ken-ichi Hanaue ◽  
Naohiko Mikami ◽  
Asuka Fujii

2019 ◽  
Vol 16 (7) ◽  
pp. 541 ◽  
Author(s):  
Pavel Ondruch ◽  
Jiri Kucerik ◽  
Daniel Tunega ◽  
Nadeesha J. Silva ◽  
Adelia J. A. Aquino ◽  
...  

Environmental contextImmobilisation of organic chemicals in soil organic matter can strongly influence their availability in the environment. We show that the presence of water clusters, called water molecule bridges, hampers the release of organic molecules from soil organic matter. Moreover, water molecule bridges are sensitive to changes in environmental conditions (e.g., temperature or moisture) which affect the release of organic molecules into the environment. AbstractWater molecule bridges (WaMB) can stabilise the supramolecular structure of soil organic matter (SOM) by connecting individual SOM molecular units. WaMB are hypothesised to act as a desorption barrier and thus to physically immobilise molecules in SOM. To test this hypothesis, we prepared two sets of soil samples – aged samples with WaMB developed, and vacuumed samples, in which WaMB were disrupted. The samples were spiked with phenol and then stored under controlled humidity. The degree of phenol immobilisation in SOM was assessed by desorption kinetics of phenol into a gas phase. This was compared with the thermal stability (T*) of WaMB obtained by modulated differential scanning calorimetry (MDSC) and the results were related to computer modelling, which provided the stability and solvation energies of phenol-WaMB-SOM models. The desorption kinetics of phenol was best described by a first-order model with two time constants ranging between 1 and 10h. In aged samples, the time constants correlated with T*, which showed that the desorption time increased with increasing WaMB stability. Molecular modelling proposed that phenol molecules are preferentially locked in nanovoids with polar OH groups pointed to WaMB in the most stable configurations. Both findings support the hypothesis that WaMB can act as a desorption barrier for phenol.


Sign in / Sign up

Export Citation Format

Share Document