My textbook only mentions “acid catalyst” when talking about reactions of 1° alcohols with hydrogen halides. It says that it requires a mixture of concentrated hydrochloric acid and a Lewis acid as a catalyst like zinc chloride to form an alkyl chloride. Any help is greatly appreciated!
Does any know for certain if PECO technology used in Molekules, specifically the “Air Pro”, release Hydroxyls into the air? I’d imagine there should probably be a post-filter right before processed air exits into the ambient air to capture any excess unreacted OH molecules.
Also, does anyone know if Hydroxyls are harmful to humans??
Secondly, how likely is it to have certain partially oxidized VOCs turn into more harmful VOCs like limonene partially oxidize to form formaldehyde
Journal of the American Chemical SocietyDOI: 10.1021/jacs.1c10612
Bo Song, Dan Lu, Anjun Qin, and Ben Zhong Tang
https://ift.tt/3zig46E
Hello,
I'm having an indoor air quality issue and I was hoping people more knowledgeable then me could give me a hand. I had an accidental spill of pyrethrin pesticide in my carpeted bedroom. I was advised to use ozone to treat the room to react with the pesticide and remove it entirely. I think it worked however I am now having serious problems breathing in the bedroom. From my understanding ozone has reacted with the carpet and carpet padding and other materials in the room to create aldehydes and acids, such as formaldehyde and formic acid. The bedroom does have a slightly sour smell to it now and it is very irritating to the eyes, nose and throat. I have purchased a hydroxyl radical generator in hopes of reacting with these gases and acids without further oxidizing the carpet. If I do in fact have an abundance of formic acid and formaldehyde buildup, can anyone confirm that hydroxyl radicals will react with them to form something safer? If not does anyone have any suggestions as to how I could react with or remove them? Are my assumptions about the chemistry that has so far occurred even correct? Any input is greatly appreciated, thank you!
I have been looking for a way to disinfect and remove odors from buildings and vehicles. I know the “industry standard” has always been ozone generator machines. I have done a fair amount of research about ozone and have learned about its limitations and dangers. They claim that ozone should be able to neutralize any organic smell and kill unwanted living organisms – whether it’s a virus, bacteria, fungi etc. However, I have seen writings that strongly discourage the use of ozone for various reasons. In my research I came across a few websites advocating the use of hydroxyl generators for the same purpose. They claim hydroxyls are more reactive with organic agents thus can do everything ozone is supposed to but much better, but the technology is just relatively new which is why it hasn’t been more widely adopted. Most of these sites are selling a hydroxyl generating product so their claims seem to be almost too good to be true. They essentially state that hydroxyl can get rid of (almost) any odor, and can kill mold, bacteria, and viruses while being safe to use around people. I am wondering if someone can corroborate these claims, or explain some of the limitations and actualities of hydroxyls as a disinfectant and sanitizer. Most of these machines cost $1k or more so I want to make sure they are really worth the money and actually work.
Synthesis of Nicocodeine (and other nicotinic esters of hydroxyl phenanthrenes) without Nicotinic Anhydride. Very promising yields reported, and quite obtainable starting materials, and a seemingly easy process. Let there be buzzing! https://patents.google.com/patent/US3131185A/en
A practice problem asks what functional group an amino group reacts with when forming a peptide bond. It says that carboxyl group is correct, and hydroxyl group is incorrect. But hydroxyl is part of carboxyl, and the hydroxyl is the part of the carboxyl that the amino group reacts with when forming a peptide bond. What am I missing here?
I drew out both structures and I can't see how 3-hydroxyl-3-methylcycloheptanone (bottom) could be neither the thermodynamic or kinetic product when only 2 possible products are formed. If there was a third possible product, then I suppose it could be both less stable than the thermodynamic and slower to form than the kinetic (i.e. then it would be neither), but in this context, I don't see how this could be true?
https://preview.redd.it/hwpkxgd2txg71.jpg?width=611&format=pjpg&auto=webp&s=1584270056f1a0d5ce344fa6f742163cfbc8880d
An international collaboration of astronomers led by a researcher from the Astrobiology Center and Queen’s University Belfast, and including researchers from Trinity College Dublin, has detected a new chemical signature in the atmosphere of an extrasolar planet (a planet that orbits a star other than our Sun).
The hydroxyl radical (OH) was found on the dayside of the exoplanet WASP-33b. This planet is a so-called ‘ultra-hot Jupiter’, a gas-giant planet orbiting its host star much closer than Mercury orbits the Sun and therefore reaching atmospheric temperatures of more than 2,500° C (hot enough to melt most metals).
The lead researcher based at the Astrobiology Center and Queen’s University Belfast, Dr Stevanus Nugroho, said: “This is the first direct evidence of OH in the atmosphere of a planet beyond the Solar System. It shows not only that astronomers can detect this molecule in exoplanet atmospheres, but also that they can begin to understand the detailed chemistry of this planetary population.”
In the Earth’s atmosphere, OH is mainly produced by the reaction of water vapour with atomic oxygen. It is a so-called ‘atmospheric detergent’ and plays a crucial role in the Earth’s atmosphere to purge pollutant gasses that can be dangerous to life (e.g., methane, carbon monoxide).
In a much hotter and bigger planet like WASP-33b, where astronomers have previously detected signs of iron and titanium oxide gas) OH plays a key role in determining the chemistry of the atmosphere through interactions with water vapour and carbon monoxide. Most of the OH in the atmosphere of WASP-33b is thought to have been produced by the destruction of water vapour due to the extremely high temperature.
“We see only a tentative and weak signal from water vapour in our data, which would support the idea that water is being destroyed to form hydroxyl in this extreme environment,” explained Dr Ernst de Mooij from Queen’s University Belfast, a co-author on this study.
To make this discovery, the team used the InfraRed Doppler (IRD) instrument at the 8.2-meter diameter Subaru Telescope located in the summit area of Maunakea in Hawai`i (about 4,200 m above sea level). This new instrument can detect atoms and molecules through their ‘spectral fingerprints,’ unique sets of dark absorption features superimposed on the rainbow of colours (or spectrum) that are emitted by stars and planets.
As the planet orbits its host star, its velocity relative to t
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Hydroxyl radicals are efficiently and continuously generated from selective electrochemical O2 reduction via 3‐electron pathway with FeCoC electrode, overcoming the rate‐limiting step of electron transfer initiated by reduction‐/oxidation‐state cycle. Fast and complete removal of organics with the apparent rate constant of 1.44±0.04 min−1 represents high potential for practical water purification.
Abstract
We reported the selective electrochemical reduction of oxygen (O2) to hydroxyl radicals (.OH) via 3‐electron pathway with FeCo alloy encapsulated by carbon aerogel (FeCoC). The graphite shell with exposed ‐COOH is conducive to the 2‐electron reduction pathway for H2O2 generation stepped by 1‐electron reduction towards to .OH. The electrocatalytic activity can be regulated by tuning the local electronic environment of carbon shell with the electrons coming from the inner FeCo alloy. The new strategy of .OH generation from electrocatalytic reduction O2 overcomes the rate‐limiting step over electron transfer initiated by reduction‐/oxidation‐state cycle in Fenton process. Fast and complete removal of ciprofloxacin was achieved within 5 min in this proposed system, the apparent rate constant (kobs) was up to 1.44±0.04 min−1, which is comparable with the state‐of‐the‐art advanced oxidation processes. The degradation rate almost remains the same after 50 successive runs, suggesting the satisfactory stability for practical applications.
https://ift.tt/316h11v
Hydrogen binding of molecules on specific solid surface is an attractive interaction that can be employed as driving force for chemical bond activation, material directed assembly, protein protection, etc. However, the lack of quantitative characterization method for hydrogen bonds (HBs) on surface seriously limits its application. Herein, we measured the standard Gibbs free energy change (ΔG 0 ) of surface HBs using NMR technique. HBs accepting ability of surface was investigated in term of comparing ΔG 0 values by employing model biomass platform 5-hydroxymethylfurfural on a series of Co-N-C-n catalysts with electron-rich doped-nitrogen contents adjusted. Reducing the ΔG 0 effectively improves HBs accepting ability of the nitrogen-doped surface, and promotes the O−H bonds selectively initiated activation in the oxidation of 5-hydroxymethylfurfural. As a result, the reaction kinetics is accelerated and the rate constant is significantly increased. In addition to excellent catalytic performance, the turnover frequency (TOF) value for this oxidation is extremely higher than the reported non-noble metal catalysts.
https://ift.tt/3iGx3cq
A so‐called “GlycoComputer” program has been developed to foresee and predict the yield and stereoselectivity of glycosylation reactions based on the properties of various donors, acceptors, activation systems and solvents. The program statistically analyzes and compares the relative reactivity value (RRV) of donors and the acceptor nucleophilic constant (Aka) of acceptors.
Abstract
The stereoselectivity and yield in glycosylation reactions are paramount but unpredictable. We have developed a database of acceptor nucleophilic constants (Aka) to quantify the nucleophilicity of hydroxyl groups in glycosylation influenced by the steric, electronic and structural effects, providing a connection between experiments and computer algorithms. The subtle reactivity differences among the hydroxyl groups on various carbohydrate molecules can be defined by Aka, which is easily accessible by a simple and convenient automation system to assure high reproducibility and accuracy. A diverse range of glycosylation donors and acceptors with well‐defined reactivity and promoters were organized and processed by the designed software program “GlycoComputer” for prediction of glycosylation reactions without involving sophisticated computational processing. The importance of Aka was further verified by random forest algorithm, and the applicability was tested by the synthesis of a Lewis A skeleton to show that the stereoselectivity and yield can be accurately estimated.
https://ift.tt/32BzYd2
Hydroxyl radicals are efficiently and continuously generated from selective electrochemical reduction O2 via 3‐electron pathway with FeCoC electrode, overcoming the rate‐limiting step of electron transfer initiated by reduction‐/oxidation‐state cycle. Fast and complete removal of organics with the apparent rate constant of 1.44±0.04 min−1 represents high potential for practical water purification.
Abstract
We reported the selective electrochemical reduction of oxygen (O2) to hydroxyl radicals (.OH) via 3‐electron pathway with FeCo alloy encapsulated by carbon aerogel (FeCoC). The graphite shell with exposed ‐COOH is conducive to the 2‐electron reduction pathway for H2O2 generation stepped by 1‐electron reduction towards to .OH. The electrocatalytic activity can be regulated by tuning the local electronic environment of carbon shell with the electrons coming from the inner FeCo alloy. The new strategy of .OH generation from electrocatalytic reduction O2 overcomes the rate‐limiting step over electron transfer initiated by reduction‐/oxidation‐state cycle in Fenton process. Fast and complete removal of ciprofloxacin was achieved within 5 min in this proposed system, the apparent rate constant (kobs) was up to 1.44±0.04 min−1, which is comparable with the state‐of‐the‐art advanced oxidation processes. The degradation rate almost remains the same after 50 successive runs, suggesting the satisfactory stability for practical applications.
https://ift.tt/316h11v
A so‐called “GlycoComputer” program has been developed to foresee and predict the yield and stereoselectivity of glycosylation reactions based on the properties of various donors, acceptors, activation systems and solvents. The program statistically analyzes and compares the relative reactivity value (RRV) of donors and the acceptor nucleophilic constant (Aka) of acceptors.
Abstract
The stereoselectivity and yield in glycosylation reactions are paramount but unpredictable. We have developed a database of acceptor nucleophilic constants (Aka) to quantify the nucleophilicity of hydroxyl groups in glycosylation influenced by the steric, electronic and structural effects, providing a connection between experiments and computer algorithms. The subtle reactivity differences among the hydroxyl groups on various carbohydrate molecules can be defined by Aka, which is easily accessible by a simple and convenient automation system to assure high reproducibility and accuracy. A diverse range of glycosylation donors and acceptors with well‐defined reactivity and promoters were organized and processed by the designed software program “GlycoComputer” for prediction of glycosylation reactions without involving sophisticated computational processing. The importance of Aka was further verified by random forest algorithm, and the applicability was tested by the synthesis of a Lewis A skeleton to show that the stereoselectivity and yield can be accurately estimated.
https://ift.tt/32BzYd2
