Questions tagged [catalysis]

This tag is appropriate for reactions, their mechanisms, their kinetics, when catalysts of any kind are involved.

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48 views

ketone and amine condensation

My question is quite easy to solve. The question simply asked to find the final product of the reaction shown below, which I did. But the my question lies in the catalyst. What is the role of the ...
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0answers
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Why are transition metal so good catalysts? [duplicate]

Transition metals (TMs) are used as catalysts in a wide variety of chemical reactions, both industrially and in living organisms. What properties do transition metals have that main group elements do ...
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Effect of short lived chemicals on global warming exceeding effect of carbon dioxide

From Wikipedia: Global Warming Potential GWP values and lifetimes: Nitrous oxide lasts about 121 years in the atmosphere, causes about 280 times as much warming over 20 years, but about 300 times as ...
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22 views

Temperature at which the reaction Oxalic acid + KMnO4 becomes autocatalytic

As described many times, the reaction between oxalic acid and potassium permanganate can be autocatalytic due to the production of Manganese ions. I've read that this only occurs at higher ...
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4answers
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What is an example of chemical reaction that can be assisted by both an inorganic catalyst and an enzyme?

I have been researching chemical reactions of inorganic catalysts and enzymes and cannot find a chemical process where an inorganic compound can be replaced by an enzyme (or vice versa) and have the ...
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1answer
83 views

Mechanism of formaldehyde / phenol condensation

The production of bakelite using this method, but with an acid as the catalyst is simple enough; a protonation of the carbonyl oxygen, followed by an electrophilic substitution to the ring. The ...
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50 views

What is the product of reaction between 2‐cyclobutyl‐2‐isopropyl‐1,3‐dioxane and hydrogen with Raney nickel?

I have 2‐cyclobutyl‐2‐isopropyl‐1,3‐dioxane (alcohol protection) and I have to react it with $\ce{H2}$ and Raney nickel, but I don't know what the product would be. I have seen a similar reaction ...
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Hydrogen peroxide and potassium iodide reactions

What is the explanation for the two possible reactions of $\ce{H2O2}$ with $\ce{KI}$ in acid media (iodide-catalyzed decomposition of hydrogen peroxide or iodide oxidation by hydrogen peroxide) and ...
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47 views

A useful way to reuse non-recyclable plastics: Turn them to petrochemicals, shall we?

I read here (https://chemistry.stackexchange.com/a/34016/101483) that strongly acidic catalysts can facilitate dimerization of alkene. With catalysts on zeolite to allow only the isooctane (octane ...
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45 views

Finding rate constant from a change in pressure experiment

I measured the change in pressure for the decomposition of hydrogen peroxide in the presence of a manganese(IV) oxide catalyst at 5 different temperatures: $$\ce{2 H2O2 (l) ->[MnO2 (s)] O2 (g) + 2 ...
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Why a catalyst is not consumed in a reaction when all steps are reversible?

It is said that a catalyst speeds up the rate of a reaction but is not consumed (assuming no side reactions take place). Suppose we have the following reaction: $$\ce{A + B <=> C} $$ catalysed ...
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1answer
107 views

Succinic anhydride esterification won't go forward

I'm trying to react succinic anhydride with a decyl alcohol to produce mono-decyl succinate. Literature and Google searches suggest that the monoesterification should proceed without catalyst. However ...
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Titanium Dioxide and plastic

How would you recommend attaching a film of anatase to a flat polycarbonate surface without compromising its photocatalytic characteristics? The self cleaning paints that I have seen are generally ...
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36 views

database for catalytic reaction mechanism

I am looking for a database containing detailed reaction mechanisms for (homogenous) catalytic reactions. Regular organic textbooks or papers generally draw some broad picture of how the mechanism may ...
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catalysts in catalytic hydrogenation

I am studying the very BASIC introduction of catalysis in general chemistry and encountered an example of a heterogeneous catalyst, which is catalytic hydrogenation of alkene into alkane using Pt/C or ...
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1answer
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Frequency Factor of the Arrhenius Equation

The question came to my mind as to whether the effect of a catalyst on a reaction included the modification of the frequency factor (or pre-exponential factor) of a reaction, shown in Arrhenius' ...
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1answer
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Ascorbic acid and aldehydes: Reaction and Influencing Metals

I've researched online and I've read that ascorbic acid can both promote oxidation and reduction depending on the conditions (I've read about trace metals but I've never found which metals affect its ...
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2answers
309 views

Why doesn't fluorine harm the ozone layer the way chlorine and bromine do? [closed]

I don't understand the chemistry here: fluorine is a halogen too. I read that fluorine in the atmosphere readily forms HF, which is (somewhat) stable and doesn't catalytically break down ozone. But, ...
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What are some convenient examples of so-called dissolved organic matter (DOM) for lab work?

Background, I have come across a chemical reaction system, occurring in nature, that apparently involves the presence of dissolved organic matter (in a catalytic role). My research returns, for ...
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2answers
69 views

PLP-Dependent Cyclization and Decarboxylation

I am looking at Compound A (see below) and am trying to figure out a decarboxylation mechanism that results in Compound B (see below). I have come up with an internal mechanism that might work that I ...
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2answers
48 views

Organic-catalysis microwaves [closed]

When we perform a organic reaction without any addtional catalyst except that the reaction is carried out under microwave condition we can accelerate this reaction in comparison with one under heating ...
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0answers
28 views

trialkyl phosphine ligands in aqueous micellar Suzuki-Miyaura coupling

I have seen $\ce{P(tBu)3HBF4}$ salt used as a precursor to the phosphine ligands for aqueous Pd-catalyzed micellar Suzuki-Miyaura coupling, but why does it work - after $\ce{Et3N}$ has liberated the ...
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What is the mechanism of benzyl ether hydrogenolysis?

The mechanism for the hydrogenation of alkenes or alkynes using Pd/C is fairly well explained to involve the absorption of hydrogen onto a metal's surface followed by the addition of that hydrogen ...
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1answer
42 views

Catalyze dehydration of formic acid [closed]

I know that formic acid will dehydrate upon heating to 100°C (under normal pressure) or adding sulfuric acid. What other catalysts can be used to induce this reaction?
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What does a sigmoidal and non-sigmoidal shape of a oxygen reduction reaction (ORR) voltammogram mean?

While testing materials for their ORR performance, one can encounter linear sweep voltammograms that have a well defined diffusion plateau and a good sigmoidal shape. On the other hand, the opposite ...
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When MnO2 acts as a catalyst to speed up the decomposition of H2O2 what does it actually do? [duplicate]

Everywhere I look it just states that $\ce{MnO2}$ acts as a catalyst but I have yet to find a simple explanation for what it actually does. What is the mechanism involved in simple terms?
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32 views

Keeping a catalyst suspension suspended

I am currently working on a heterogeneous photocatalyst project. We are having significant problems with the catalyst not staying suspended in an aqueous solution. What can I do to prevent ...
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21 views

Doubt's regarding inputting surface reaction for Chemkin Pro

I want to simulate the reaction of a mixture of ethanol and Hydrogen Peroxide on $\ce{Pt}$ using Chemkin Pro. I want to create a surface input files which will include surface reaction mechanism of ...
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Why is copper(II) used a catalyst here instead of as an intermediate?

Photochromic glass, used for sunglasses darkens when exposed to bright light and becomes more transparent again when the light is less bright. The depth of color of the glass is related to the ...
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32 views

Catalysts and activation energy

Do catalysts increase rate of reaction only by decreasing activation energy? Or can they affect the Arrhenius factor or reaction orders? Like if one catalyst is more effective at increasing rate of ...
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2answers
58 views

Why am I getting higher conversion values of isopropanol dehydration over a zeolite catalyst than n-propanol dehydration?

The two process are run separetly but under the same condition, same activation of the catalyst, same reaction temperature, same flow. The initial conversion of n-propanol is ~50% and isopropanol ~70%....
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1answer
79 views

Stubborn CuAAC reaction as derivatization for ESI-MS

Problem description I have a substance that is extremely non-polar and therefore does not ionize in the ESI source, which makes it impossible to quantify small amounts. The substance contains only two ...
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1answer
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What is the opposite of a catalyst and examples? [duplicate]

I remember a while ago I heard of something that slowed reactions and was effectively the opposite of a catalyst. What is this called? Also would appreciate examples and an explanation of their uses ...
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What are the most potent hydrogen peroxide decomposition catalysts available to an amateur? [closed]

Some months ago I was playing with $60\,\%$ $\ce{H2O2}$ and unknowingly I used a silver spoon to transfer the liquid from a container, and the peroxide immediately started bubbling (it did look and ...
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1answer
83 views

The dissociation of hydrogen on UO2 and PuO2 surfaces: Homolytic or heterolytic?

I have seen that $\ce{H2}$ can dissociate on a metal-oxide surface by two methods: Heterolytically, forming a proton-$\ce{O}$ bond ($\ce{OH}$ group) and a hydride-metal bond ($\ce{M-H}$) on a metal-...
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2answers
57 views

Oxidation to allylic alcohols without stoichiometric metal reagents

Common methods of oxidation of alkenes to allylic alcohols in one step usually use stoichiometric metal oxidants, e.g., sodium dichromate. Without using this type of reagent, are the other methods ...
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0answers
56 views

Can a catalyst appear in the rate equation? [duplicate]

According to Wikipedia: Chemical reactions occur faster in the presence of a catalyst because the catalyst provides an alternative reaction pathway with a lower activation energy than the non-...
2
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1answer
39 views

Nickel salts from hypochlorites

(JUST A HEADS UP I’m 15 years old and new to chemistry) So I was recently looking around the house looking for products that I can extract chemicals from and I found a bottle of cleaning Vinegar ( 5% ...
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19 views

catalytic activity of Pd and Pt

what phenomenon takes place during catalytic activity of Pd and Pt during hydrogenation ? in some books it is given as absorption,in others adsorption .some say that it is occlusion . please help me
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1answer
176 views

Proposed mechanism for the catalyzed oxidation of CO by O3: Are NO and NO2 catalysts or intermediates?

The steps below represent a proposed mechanism for the catalyzed oxidation of $\ce{CO}$ by $\ce{O3}$: $$\begin{align} &\text{Step 1: } & \ce{NO2(g) + CO(g) &-> NO(g) + CO2(g)} \\ &...
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2answers
175 views

What is heterogeneous catalysis in gas phase?

Give examples of heterogeneous catalysis (i) in gas phase and (ii) in liquid phase. Now, I came to know that heterogeneous catalysis involves different phases between the catalyst used and the ...
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1answer
85 views

What is the rate expression for decomposition of $\ce{H2O2}$ in the presence of a catalyst?

What is the rate expression for decomposition of $\ce{H2O2}$ in the presence of a catalyst? As far as I know for catalase, it is like this: $$\ce{Rate = k[H2O2][Catalase]}$$ I don't know what it is ...
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2answers
297 views

Nitrocellulose (flash paper) synthesis without Sulfuric Acid?

According to the Wikipedia page on Nitrocellulose: The process uses nitric acid to convert cellulose into cellulose nitrate and water: $$\ce{3HNO3 + C6H10O5 ->[H2SO4] C6H7(NO2)3O5 + 3H2O}$$ ...
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1answer
90 views

what catalyst to use for the reaction between AgNO3 and NaCl? [closed]

What is the best catalyst to use for the reaction between AgNO3 and NaCl that would result in a change in activation of energy so therefore more precipitate formed. Please give me the ways I can ...
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24 views

Efficiency of H production from FeOOH catalyst?

Research has recently found that FeOOH is 25 times better at hydrogen production than titanium dioxide. Today, a new electrolysis plant delivers energy efficiency of around 80%. Is 25x the Honda-...
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1answer
154 views

Hydrogen peroxide / sodium or potassium permanganate: reaction type

I have some people on youtube stating the steam generating reaction of $$\ce{3H2O2 + 2KMnO4 → 3O2 + 2MnO2 + 2KOH + 2H2O}$$ is catalytic, from where I'm sitting it is purely stoichiometric. Can ...
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41 views

Curtin-Hammett principle to evaluate alkene insertion

Given an unsymmetrical alkene in a simple non-stereoselective catalytic hydrogenation reaction. If one would want to investigate the nuances in the catalytic cycle of a dihydride complex leading to ...
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1answer
92 views

How can subtilisin still function without its catalytic triad?

I read chapter 9 in the book Biochemistry (5th edition), by Berg, Tymoczko, and Stryer (provided in the NCBI site here). It describes the mechanism of action of the chymotrypsin enzyme. The catalysis ...
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1answer
292 views

What is the “mechanism” of the decomposition of hydrogen peroxide?

In my classwork on the decomposition reaction of hydrogen peroxide by catalase, I wrote the following equation: $$\ce{2H2O2 -> 2H2O + O2}$$ However, my teacher said that I should go further in ...
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What is it that makes this noncontact catalytic system unique in 2020?

Phys.org's Accelerating chemical reactions without direct contact with a catalyst discusses the new Science Advances paper Noncontact catalysis: Initiation of selective ethylbenzene oxidation by Au ...

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