Questions tagged [catalysis]

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

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24 views

Why is the synthesis of graphene through alkyne trimerization not viable?

I have been looking for a rationale on this as massive polycyclic aromatic hydrocarbons have been synthesized this way, and with Graphene just being an indefinite expansion of aromatic rings, this has ...
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75 views

How can a catalyst be selective if it does not change the equilibrium constants?

\begin{align} \ce{CO(g) + 3H2(g) &->[Ni] CH4(g) + H2O(g)}\\ \ce{CO(g) + 2H2(g) &->[Cu/ZnO-Cr2O3] CH3OH(g) }\\ \ce{CO(g) + H2(g) &->[Cu] HCHO(g) } \end{align} As we see here, ...
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106 views

Which amines show N−N coupling reaction?

We add 1 equivalent of $\ce{KCN}$ followed by catalytic reduction via Lindlar's reagent $(\ce{H2}/\ce{Pt})$ to 4-chlorobenzyl chloride (1). Verify whether the product (P) obtained will undergo an N−N ...
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76 views

How are Silanol groups functionalized unto mesoporous silica structures?

As described in this research paper: Immobilization of Jacobsen type catalysts on modified silica, Jairo Cubillos , Edwing Grajales, Santiago Vásquez, Consuelo Montes de Correa, Rev. Fac. Ing. Univ. ...
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28 views

Regulator oxidizing NO to NO2

I have a regulator that is somehow oxidizing NO to NO2. Using a different regulator does not cause this same issue. I was wondering what could possible be contaminating the regulator that would ...
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15 views

Recommendation for a searchable database for ligand search in homogenous catalysis?

I am currently trying to preform a database search for phosphite/phosphine ligands that have specific properties (bite-angles, electronic parameters etc.) and don't know which databases there are, ...
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29 views

Can an alloy catalyst change during a reaction?

I am studying the reaction pathway of oxygen evolution reaction (OER) on a PtNi alloy catalyst using density functional theory (DFT). What I found is that, for different intermediates, the most stable ...
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37 views

Why is the Tolman electronic parameter defined the way that it is?

I'm currently writing up a report on Hydrocyanation and I've been reading up on parameters people regularly use to justify their observations in regard to the performance of certain catalyst systems ...
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53 views

Purification of Buchwald-Hartwig amination

I am conducting a synthesis involving Buchwald-Hartwig amination. I use $\ce{Pd2(dba)3}$, $\ce{P(o-tol)3}$, and $\ce{Et3N}$ as base. In many proposed mechanisms, they often omit the precatalyst. I ...
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156 views

Decarboxylation of primary amino acids

Since primary amino acids like glycine, alanine can't be decarboxylated under oxidative conditions, what would be the best catalyst for this reaction? I was thinking about copying decarboxylases with $...
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Advantages of p-toluenesulfonic acid over sulfuric acid in the formation of acetals

I am currently working on an undergraduate experiment to form a cyclic acetal. We were asked to use p-toluenesulfonic acid as a catalyst rather than sulfuric acid. This seems to be common practice ...
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Why do poisoned catalysts (Lindlar, nickel borate) result in partial hydrogenation of alkynes?

I read that alkene is more reactive than alkyne, so in hydrogenation of alkynes, it's difficult to isolate the alkenes. But with poisoned catalysts like Lindlar's catalyst or Nickel-Boron (Ni2B), they ...
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38 views

What is the rate constant k for the reaction between potassium manganate and oxalic acid?

For my school's chemistry classes, I am investigating the kinetics of the redox reaction between $\ce{K2MnO4}$ and $\ce{C2H2O4}$. I analyzed the data using a colorimeter set to $\pu{565nm}$. ...
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1answer
66 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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45 views

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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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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390 views

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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112 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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52 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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1answer
84 views

What are the limits of size differences in a host–guest complex?

We learn in my chemistry course that there must be a snug fit for a host-guest complex to form. So, something like benzene (0.6 nm in diameter) can form a host-guest complex with a β-cyclodextrin host ...
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83 views

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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1answer
53 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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46 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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119 views

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
179 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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33 views

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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37 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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30 views

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
105 views

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
35 views

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
471 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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38 views

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
78 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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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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139 views

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
46 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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23 views

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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49 views

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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34 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
59 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
86 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
68 views

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
85 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
71 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
59 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
46 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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