Questions tagged [reaction-control]

Questions related to the chemical and physical influences that influence the rate and probability of chemical reactions. Not to be confused with [catalysis] or [reaction-mechanism].

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2 votes
0 answers
21 views

Electrophilic fluorination power: selectfluor vs NFSI

I want to fluorinate the methylene hydrogens between an aryl group and a phosponate ester. The reaction is similar (not identical) to this one: For some reason on the literature people are using very ...
13 votes
1 answer
450 views

Aza-enolates: why no reaction at N

My understanding is that aza-enolates have an advantage over enamines in enolate-type alkylations because the reaction at N is less likely. As a result, unactivated electrophiles can be used (i.e. ...
0 votes
1 answer
50 views

Questions on protonation / substituent effects on the energies of HOMO and LUMO

I am trying to understand mechanisms through HOMO/LUMO and am struggling to understand 3 points from a lecture slide I found on the internet: Focusing on sigma*(C-F), sigma*(C-O) and sigma*(C-C), I ...
-1 votes
0 answers
33 views

Is the Trans Influence Truly Thermodynamic or part kinetic? If the starting complex is raised by a strong σ donor, won't the products be raised too?

I am a little confused about the trans influence and trans effect, but mainly the trans influence. I think I understand the trans effect as certain ligands being able to better stabilise the ...
10 votes
4 answers
3k views

Why do we use Δ to mean heating?

To express heating, we usually use $\Delta$ over reaction arrows like \begin{align} \ce{CaCO3 ->[\Delta] CaO +CO2}. \end{align} Why do we use $\Delta$ to mean heating during chemical reactions? I ...
-1 votes
1 answer
151 views

Does the equilibrium constant of an ideal liquid mixture reaction depend on pressure?

I want to calculate the equilibrium constant K[T] for a the following reaction: $$\ce{CH3OH(l) + C4H8(l) -> C5H12O(l)}$$ It is assumed that the mixture is ideal and the reaction takes place at 14 ...
15 votes
3 answers
3k views

Does gravity affect the rate of a chemical reaction?

For example, on planets with lower gravity, would the rate of reactions be lower because the reactants are slower to mix with one another?
11 votes
0 answers
1k views

Role of pH in azo C-coupling reaction, continued

In the question, "What is the role of pH in azo coupling reaction of diazonium with phenol and aniline?" asked by @DhrubaBanerjee and answered by @Klaus-DieterWarzecha, I find several ends ...
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0 answers
50 views

Oxidize Zinc or Nickel in black nickel plating to get browns?

I have a black nickel plating solution that is comprised of the following: Nickel (II) Sulfate (45-50% by weight) Zinc Sulfate Heptahydrate (20-24%) Ammonium Thiocyanate (20-23%) Zinc Chloride (1-3%) ...
-1 votes
1 answer
124 views

Why is there difference in reactions in alcoholic and aqueous medium while both are polar protic solvents?

We use an alcoholic medium for reactions in which we want to prevent the characteristics of the anionic species and an aqueous medium for the reactions in which we want to control the activity of the ...
0 votes
0 answers
43 views

Pure MEA vs Aqueous MEA Solution for CO2 Scrubbing

I was wondering if using pure MEA (Monoethanolamine) or a MEA solution using water would be a better solution for scrubbing $\ce{CO_2}$. Based on this image, I would think the key reaction would be ...
1 vote
0 answers
44 views

Efficiency of Gas Liquid Reactions Using Different Methods

I am looking to react MEA (monoethanolamine) with $\ce{CO_2}$. I was planning on doing this reaction by bubbling atmospheric air through water by using an air pump. I have researched that a smaller ...
-2 votes
2 answers
373 views

How much can we extend the Finkelstein reaction?

Finkelstein reaction explicitly entails the conversion of an alkyl chloride or alkyl bromide to alkyl iodide by treatment with sodium iodide in acetone. $$\ce{R−X + NaI→[acetone] R−I + NaX↓ }\\ \ce{(X$...
-1 votes
1 answer
192 views

Rates of a chemical reaction

Consider the reaction between Calcium Carbonate and Hydrochloric Acid. I understand the reaction rate can be increased by increasing the concentration of reactants. However I can't seem to understand ...
2 votes
3 answers
195 views

Approximate calculations of the product distribution under kinetic control

What is the product distribution when the energy difference between the transition states (∆TS = TS1 – TS2), is at 2 kcal/mol and when it is at 5 kcal/mol (assuming room temperature)? I know that 1.4 ...
0 votes
0 answers
83 views

What are the products of 1 mol of vitamin C (C6H8O6) and 1 mol of hydrogen peroxide (H2O2)?

Basic stoichiometry suggests that $\pu{1 mol}$ of vitamin C($\ce{C6H8O6}$) react with $\ce{1 mol}$ hydrogen peroxide ($\ce{H2O2}$) to produce one $\ce{1 mol}$ dehydroascorbic acid DHA($\ce{C6H6O6}$)? ...
2 votes
1 answer
664 views

What is the difference between differential yield and selectivity?

I have a hard time understanding the difference between the differential yield and overall selectivity of a reaction. Levenspiel, Chemical Reaction Engineering writes: For convenience in evaluating ...
8 votes
3 answers
9k views

Why do we need sulfuric acid in creating alkyl bromide and not in creating alkyl iodide from alcohol and hydrogen halide?

i) $\ce{R-CH_2-OH + HBr ->[H_2SO_4] R-CH_2-Br + H_2O}$ ii) $\ce{R-CH_2-OH + HI -> R-CH_2-I + H_2O}$ What role does sulfuric acid play in the first reaction? Why are we not using it in the ...
7 votes
2 answers
897 views

Does high pressure reverse reaction between zinc and sulfuric acid?

When zinc is added to sulfuric acid, it undergoes a chemical reaction that generates hydrogen gas and zinc sulfate. Can this reaction be reversed by applying pressure to the products converting them ...
-1 votes
1 answer
3k views

Drano and Bleach reaction? [closed]

I’m not sure if anyone can answer this but I might’ve messed up, or I’m just overreacting. My bathtub has been clogged for about a month now and I used a splash of Drano to see if it would do anything,...
1 vote
0 answers
109 views

Activation Energy in silicon etching

I'm trying to understand what does activation energy means when we're talking about etching. Here's what I understand so far: activation energy is the energy required by the system to undergo a ...
2 votes
1 answer
286 views

How strong (molarity) does NaOH solution need to be to saponify fats?

I have some large cast iron hob grilles of an awkward shape, and want to clean the burnt-on fat from them using NaOH solution. I have two options Use a small amount of a strong solution, with a brush ...
0 votes
1 answer
121 views

How does Hess' Law work exactly? [closed]

So I am talking about complicated compounds and not simple reactions where you subtract heats of formation. I was trying to find the heat of reaction for an aryl substituted methyl aryl sulfide being ...
3 votes
0 answers
79 views

Why does Bachmann reaction differ in batch characteristics as opposed to flow characteristics

I have studied this reaction for over a year and it makes zero sense. When synthesizing HMX from Bachmann reaction, an important intermediate is DPT. DPT is formed by reaction of nitric and hexamine ...
3 votes
1 answer
2k views

Arrhenius equation in exothermic reactions

According to the Arrhenius equation, the rate of reaction increases when the temperature increases. But according to Le Chatelier's principle, the reaction rate decreases when the temperature ...
3 votes
3 answers
625 views

Can we make chemical bonds using light, instead of breaking them?

I am trying to bridge a conceptual understanding of how light affects both breaking and forming bonds. When bonds are broken, energy is absorbed (endothermic process). Conversely, when bonds are made, ...
1 vote
1 answer
360 views

Oxidation Reactions/Reactivity of Manganese Metal in Air and Water

I am planning on doing some reactions that lead to Manganese metal and a neutral solution containing $\ce{Mn^{2+}}$ as by-products, and I wanted to try some things out with the Manganese as well. ...
1 vote
1 answer
213 views

How do you rewrite molarity to weight percentage or volume percentage?

Suppose I have a molar concentration $[C]$ in $mol/m^3$ in a continuous reactor, from which the differential equation is as follows: $ \frac{\partial [C]}{\partial t} = k[A][B] + \phi C_{,in} - \phi ...
0 votes
0 answers
43 views

What are the reaction rate constants, or coefficients, of coal combustion at high temperature?

Say I have coal that I will combust with $\ce{O2}$ at a high temperature of $\pu{1600-1800 K}$, what are the reaction rate constants, or coefficients, of the main reactions? I have searched around ...
1 vote
0 answers
475 views

How does the temperature of HCl affect the reaction rate of HCl & Mg reaction?

I'm Olivia. I'm experimenting with HCl and Mg. My purpose is to find the change of the reaction rate while I increase the temperature of HCi. According to the study, when I increase the temperature of ...
2 votes
1 answer
481 views

Titanium reaction with Sodium Percarbonate solution

I've been reading about a process for darkening Titanium using Sodium Percarbonate that consists of the following steps: Prepare Sodium Percarbonate solution 1:5 with boiling water Soak titanium ...
0 votes
0 answers
56 views

Reaction between iron oxides to form magnetite

In the notes of a course it is indicated that the reaction of formation of magnetite from iron oxides can only take place if the partial pressure of oxygen is higher than 1 nanobar. $\ce{FeO}$ + $\ce{...
1 vote
1 answer
246 views

Reaction of Grignard reagents with phosphoric acid derivatives

The use of Grignard reagents that people are most familiar with is the production of tertiary alcohols by reaction with a suitable carbonyl compound, whether it be an ester, ketone, or aldehyde. As I ...
2 votes
0 answers
60 views

Is this a valid interpretation of the Mean relative speed between two (Maxwell-Boltzmann) species?

In textbooks, the collision frequency $Z_{ab}$ is always given as something like: $$Z_{ab} = n_an_b\sigma_{ab} \Bigg(\frac{8 k T}{\pi \mu}\Bigg)^{1/2}= n_an_b\sigma_{ab} \bar{C}_{rel}$$ where the ...
1 vote
0 answers
40 views

Are there any pathways that can change a solution to all colors of the rainbow?

The challenge's like this. Suppose you have a beaker containing a liquid of transparent or any color. You add some drops of another liquid and the beaker turns into, say, red after some swishing. You ...
3 votes
0 answers
111 views

What is meant by "analogous reactions" in the Bell-Evans Polanyi Principle?

The BEP principle says that for analogous reactions, enthalpy change and activation energy are linearly related. What is meant by analogous reactions? Eg. For electrophilic addition of HBr to pent-1-...
6 votes
1 answer
2k views

Formation of Aniline from Chlorobenzene

My textbook says: When chlorobenzene is treated with aqueous ammonia at 473K under a pressure of 60 atmospheres in presence of cuprous oxide or cuprous chloride, aniline is formed. Notice the ...
0 votes
0 answers
266 views

Parameters of NaHCO3 + citric acid + H2O + NaCl mixture potentially impacting functional efficacy in pest control application?

I have been searching for infomation on this application, but have some specific questions that I have not seen directly addressed in the Google/Stack Exchange posts I've come across thus far; below ...
6 votes
0 answers
267 views

Temperature control and side reactions in PPAA (T3P) couplings

In a lot of procedures for amide couplings (acid + amine) using PPAA, the coupling agent is added to a cooled solution of the acid, amine, and a non-nucleophilic base such as DIPEA. This is done even ...
2 votes
1 answer
1k views

Free rotation of sigma bonds; diastereomer formation; thermodynamic and kinetic products

For the reaction of 1,3-butadiene with DBr (D = heavy hydrogen), I found that several possible products could be formed. Kinetic products A pair of enantiomers is formed. One of the pi bonds ...
6 votes
1 answer
272 views

Decarboxylation of THCA during CO2 Extraction of Cannabis

We have a strange problem. We are performing CO2 extraction on cannabis and we are seeing considerable decarboxylation of THCA to THC. We have high quality temperature sensors at the heat exchangers, ...
0 votes
1 answer
813 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 ...
2 votes
0 answers
593 views

CSTR reaction cooling jacket - Transfer Functions

I have a CSTR where an irreversible exothermic liquid reaction takes place. Coolant is flowing in the jacket of the tank to regulate the temperature of the fluid in the reactor and control in this way ...
0 votes
0 answers
59 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 ...
0 votes
0 answers
122 views

Why use Stork enamine alkylation?

I recently learned about the Stork enamine alkylation method of adding electrophiles to the beta carboxyl position on a molecule. But I can't seem to find out why a direct synthesis is not possible (...
-1 votes
1 answer
130 views

Good Hess's Law experiment [closed]

I am doing an Internal Assessment for my IB chemistry class, and I want to do something on Hess's Law, and I'll be doing it simulation based, using this website. With the solutions and equipment on ...
-1 votes
2 answers
2k views

Real life examples of chemical reactions [closed]

For my upcoming lab report, I want to look at exactly how a simple variable, such as heat or surface area, affects a reaction. But I'm having trouble finding a reaction to test this on, as my results ...
1 vote
1 answer
112 views

Chemical reaction of radicals with different multiplicity

I am studying the chemical reaction of radicals by computational chemistry software. I just want to know what is the rules for multiplicity. I have two radicals for which, the ground state of one is a ...
-3 votes
1 answer
274 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 ...
0 votes
0 answers
387 views

What does spontaneous mean in term of forward and reverse reactions?

I just learnt about Gibb's Free Energy and was thinking about an exothermic reaction with a negative change in entropy. This means that the reaction would occur at low temperatures. But that means ...