Questions tagged [catalysis]

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

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1answer
25 views

how to calculate atom economy of the following reaction? [closed]

Let me know how to calculate the atom economy for the first reaction. I am attaching my attempt.
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0answers
28 views

Calculate rate constant from conversion and space velocity

For a catalytic reactor I have measured conversion rates for different temperatures and space velocities. To compare these results with other measurements I would like calculate the rate constant to ...
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1answer
75 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
33 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
48 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-...
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1answer
34 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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14 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
116 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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1answer
53 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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39 views

Reaction order of a reaction with catalyst

I am given the following $\ce{H2O2 -> H2O + 1/2 O2}$ (catalysed by $\ce{KI}$) There are two solutions. $[\ce{H2O2}]$ is the same in both solutions but $[\ce{I-}]$ is $\pu{0.01M}$ and $\pu{0.005M}$,...
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1answer
45 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
73 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
49 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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20 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
52 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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33 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
61 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
75 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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80 views

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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1answer
43 views

Is there any chemical that can catalyze “reverse combustion?” [closed]

I am trying to build a machine that converts carbon dioxide and water into gasoline (i.e. octane). Because the energy needs are so large, is there any catalyst chemical that can cause "reverse ...
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1answer
81 views

How to precipitate Chloroplatinic acid? [closed]

For the precipitation reaction, I have to react $\ce{H2PtCl6}$ with $\ce{(NH4)2CO3}$ while maintaining the $\ce{pH}$ in the range of 7-8 at 60 °C. But the problem is Chloroplatinic acid is not ...
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1answer
181 views

Specific reduction of certain functional groups

Consider the compound $\ce{Alkyl-(4 oxocyclopent-2-ene)carboxylate (A)}$. For example consider- Now consider the operations: $\ce{1. (A) + (i)BH3/THF (ii) H+}$ $\ce{2. (A) + H2/Pt}$ ...
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2answers
87 views

Determining a molecular formula of the catalyst for polymerisation of butadiene

I've got the following question in a workbook which I need to solve: A $\pu{50 g}$ sample of an experimental catalyst used in the polymerisation of butadiene is made up of $\pu{11.65 g}$ of $\ce{Co}...
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2answers
123 views

What is the rate equation of decomposition of H2O2 with catalysts?

What is the rate equation of this reaction with the presence of catalysts $\ce{MnO2}$, $\ce{PbO2}$ and $\ce{Fe2O3}$? (asking for each of them, separately, not altogether) $$\ce{2H2O2 -> 2H2O + O2}$...
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1answer
103 views

Triphenylphosphine (PPh3) vs. 1,2-bis(diphenylphosphino)ethane (dppe) ligand?

What about $\ce{NiCl2(dppe)}$ makes it a more efficient catalyst for Suzuki cross-coupling as opposed to $\ce{NiCl2(PPh3)2}$ or $\ce{NiCl2(PCy3)2}$? How does the dppe ligand increase the reactivity of ...
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0answers
37 views

Source of highly nucleophilic iodide [closed]

What is be the best commercially available source of highly nucleophilic iodide in non-polar solvent? Solvents used are cyclohexane, benzene, chlorobenzene. I can get ahold of bromide quaternary ...
3
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0answers
55 views

Why is NOₓ conversion low at fuel rich conditions in a three-way catalytic converter?

$$ \begin{align} &\text{Oxidation:} &\quad \ce{2 CO + O2 &-> 2 CO2}\\ & & \ce{``HC" + O2 &-> CO2 + H2O}\\ & & & \\ &\text{Reduction:} &\quad \ce{2 CO +...
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1answer
40 views

Why should we be interested in catalyst for electrolysis?

I've been reading papers on Phosphided metals (CoP, NiP, FeP) as a catalyst for electrolysis. They increase the current density of the cell for a voltage. If it still requires 39.4 kilowatt-hours ...
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0answers
34 views

Are there any chemical pathways or catalysts that could produce electricity from fossil fuels without combustion?

While fossil fuels are dense in energy, I have known only one way to retrieve energy from them, namely, to burn them. I wish we could have a way to get energy from them without combustion. Is there ...
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0answers
44 views

Why Does Adding Catalyst Slow Down My Reaction?

I currently did a lab where I was meant to identify factors that increase the rate of the reaction. I reacted Glucose with Potassium Permanganate and used Sulfuric Acid as a catalyst. But in my ...
3
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1answer
65 views

CuSO4 in SO2/SO3 gas sampling in Sulphuric Acid Production

What role does $\ce{CuSO4}$ has in the gas sampling of an $\ce{SO2/SO3}$ gas mix in a catalytic converter for sulphuric acid production? To give you a little context: We take gas samples from the ...
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1answer
84 views

Catalyst discovery

How are catalysts for chemical reactions found? Given a hoped for reaction, let's take the hydrogenation of carbon monoxide to methanol as an example, do chemists: Proceed directly from some ...
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1answer
217 views

Aluminium Oxide as Dehydrating agent

According to this paper on dehydration by $\ce{Al2O3}$, Dehydroxylation causes a surface defects as Lewis acidic centers (unsaturated $\ce{Al^3+}$ ions) and basic Lewis centers ($\ce{O^2-}$ ions) ...
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0answers
33 views

Difference between Ziegler–Natta method and Phillips method [closed]

I have to compare the similarities and differences between the Zieglerr–Natta method and Phillips method of producing polyethylene. However, the only difference I can find is the difference in ...
1
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1answer
58 views

Can oxygen gas in air react with Mn3O4 to form MnO2?

I think $\ce{MnO2}$ at high temperature can be used as a catalyst for $\ce{SO2 + O2 -> SO3}$: $$ \begin{align} \ce{MnO2 + SO2 &-> MnSO4}\tag{1}\\ \ce{3 MnSO4 &-> Mn3O4 + SO2 + 2 SO3}\...
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2answers
71 views

Catalyst that combines oxygen and hydrogen

Are there any known catalysts that can combine hydrogen and oxygen into water? Does this type of reaction have a name? Trying to search for information, it seems to be all about splitting hydrogen ...
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0answers
163 views

Reaction between Sodium Thiosulfate and Iron Chloride

I'm doing a paper on catalytic effectiveness in this reaction, and am trying to identify how the catalysts are speeding up the reaction. Based on what I can find, $\ce{Fe}$ starts as $\ce{Fe^3+}$, ...
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0answers
51 views

CuAAC “Click” reaction giving inconsistent results

I apologize in advance for the large amount of text and thank all those who take the time to read it. The "Click" reaction after Fokin and Sharpless is known to achieve high yields without long ...
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0answers
47 views

Is activation energy directly related to the reaction rate? (keeping the temperature, concentration, catalyst, particle size and pressure constant)

For different chemical reactions, does the activation energy of that reaction directly relate to the reaction rate? In other words, would a reaction always be slower if it had a higher activation ...
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0answers
26 views

Will a Lewis acid catalyze the reaction of HBr with primary alcohols?

It is well-established that a Lewis acid catalyst (popularly $\ce{ZnCl2})$ is necessary to form an alkyl chloride when reacting $\ce{HCl}$ with a primary alcohol. This actually changes the mechanism: ...
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1answer
68 views

How can some enzymes work faster than the diffusion rates of the reactants allow?

Quoting Wikipedia: "Some enzymes operate with kinetics which are faster than diffusion rates, which would seem to be impossible." Which are those enzymes and how can they be so fast? One example is ...
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16 views

Catalyzing the breakdown of Si-O bonds

What catalysts can catalyze the breakdown of (Si-O) bond ? Can you mention some books(ebooks or hard cover) or websites that cover a lot of information about (Si-O) bond characteristics? I have ...
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0answers
23 views

What is the equation that describes the variation in concentration of an inhibitor in an heterogeneous catalysis?

I find myself in quite a pinch: I have to sustain a Chemical Physics exam, and I know for a fact that the professor often asks this particular question: Suppose that we have both a reacting species ...
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0answers
25 views

Why isn't the base reformed in base-catalyzed hydrolysis of esters?

In acid-catalyzed hydrolysis, the hydronium ion is clearly reformed; however, in the base-catalyzed hydrolysis, an alcohol is formed as a by-product, but the strong base isn't reformed. Is it a ...
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2answers
743 views

Rate of reaction graph

An autocatalytic reaction is a reaction in which one of the products catalyses the reaction. In general what will be the shape of curve if the rate of reaction was plotted against time for an ...
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1answer
27 views

Catalysts to accelerate foamy polyurethane reaction

This is the reaction that I am referring to: https://www.youtube.com/watch?v=EoRUSo0BWC0 I am interested in finding catalysts to accelerate this fun chemistry demonstration. I have heard that some ...
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1answer
63 views

Is activation energy time-dependent?

I was thinking lately about activation energy's dependency on time. I couldn't find any information on the internet. Only answer that came up to my mind is the fact that activation energy is constant, ...
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1answer
134 views

What is the crystal structure of bismuth oxyhydroxyphosphate (BOHP)?

The recent Chemical & Engineering News article Photocatalyst shreds drinking water contaminant PFOA report the following: Cates and his colleagues made an accidental breakthrough while testing ...
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1answer
83 views

Help with finding the right catalyst and reaction conditions for hydroamination reaction

A friend of mine, final year PhD, and I, final year Bachelor, are focusing on hydroamination reactions. In particular those with secondary amines and substituted alkenes. The reaction in particular is ...
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0answers
17 views

Why do electrocatalysts based on polyoxometalates and carbon materials have a weaker activity/performance in acidic media?

I am testing now some doped N and S doped carbon nanomaterials alone and immobilized in POM for the purpose of developing a nanocomposite that can serve as an electrocatalyst for energy-related ...

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