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# Reaction Kinetics - Science topic

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Questions related to Reaction Kinetics

For the elementary reaction:

**HO2 + O <=> OH + O2**, If G (which can be regarded as an oxygen isotope) is used to replace one of the O in HO2, make it become HOG, which of the following reaction formula is correct? Or both exist, but at different rates?**a: HOG + O <=> GH + O2; b: HOG + O <=> OH + OG;**

I know some common sense (for example, the law of dehydrogenation of hydrocarbon fuel), but I am not clear about such elementary reactions.

I wish you a wonderful day.

I appreciate it if anyone can offer any help.

Method for calculating reaction kinetics

These types of figures are required in reaction kinetics modeling work.

#figure

#plot

#Histogram

#reaction_kinetics

#chemical_kinetics

#combustion

#combustion_kinetics

Hello,

This might be a very ridiculous general question but here we go:

I am trying to find kinetic parameters for the metabolism of a drug by the enzyme CYP3A4. The problem is, all literature Vmax values are specific activities either in pmol/min/mg or pmol/min/pmol CYP3A4, but I need Vmax values to be in the form: mol/h or mol/(h*L) ( for a systems biology application that uses these units in rate laws)

I am not an expert on enzyme kinetics, so I am not sure how one makes the conversion to fit the Vmax data into a this format. Do we need the enzyme concentration (in g/L or in M), as well as the incubation volume?

Some insight would be highly appreciated.

The rate of a chemical reaction is typically given by r = k[A][B] where [-] indicates concentration. However, it seems to make sense to use r = k{A}{B}, where {-} indicates activities, since the activity represents the effective concentration. I've found two papers that use this method for the hydration kinetics of carbon dioxide, with good results:

However, in the classic work on "Gas-liquid reactions", Danckwerts says the following:

"It is a mistake to suppose that, when the reactants are non-ideal solutes, thermodynamic activities should be substituted for concentrations in the rate-equation, and that the corresponding rate-constant will then be independent of composition. This formulation is misconceived in principle, and in practice the use of concentrations usually leads to somewhat better results that the use of activities"

I know the Danckwerts book is from 1970 and the papers above are from 2007 and 2010, but they knew their stuff back in the day! What has changed? Why is this formulation misconceived? And who is right?

Lastly, I know the rate equation is itself a simplification of the actual process, but if I want to get an accurate estimate, should I use concentrations or activities?

Reaction kinetics for 1-Butene Epoxidation is very limited and difficult to find. However, the propene epoxidation reaction kinetics is available. Will the difference in constants and other parameters will be huge? Can I use this for education purpose? Is there any way we can get the kinetics of Butene Epoxidation from Propene Epoxidation kinetic parameters ?

we need the reaction kinetics for light naphtha isomerization when catalyst pt base on chlorinated gamma alumina is used.please guide us, in which book or article we can find it.

Could TOF be affected by any catalyst properties or reactor conditions? Please share more light on the choice of your answer (other than Yes/No) and if possible provide supporting materials. Thank you all.

I have obtained zpe corrected energies for reactant, TS and product states. I can plot a general scattered plot using MS Excel (but not that great). I would like to know how to plot a reaction profile as one would find in publications.

I have also attached my suggested excel worksheet below.

Thank you

D L S Dinuka

P.S. I need to compare several candidate profiles overlapped so using IRC method wasn't successful.

Maybe increasing or decreasing it. Please do support your comments with relevant literature, if possible. Thanks

I have to calculate the order of reaction and reaction kinetics for a reaction which needs to be run in semi batch mode due to high exothermicity. How can I possible run an experiment and when the samples should be collected in order to plot C vs.t graph. The conversion is very fast so how do I know the concentration of unreacted is from the initial time t=0 or from the addition due to semibatch mode?

CFD modelling is a useful tool to examine the performance of electrochemical cells for specific reactions over suitable catalysts. Currently, I am working on using CFD modelling framework to describe coupled mass transport, hydrodynamics of flow, chemical (homogeneous) and electrochemical (heterogeneous) reaction kinetics in an electrochemical flow cell for a specific oxidation reaction on an electrode.

As I plan to use Ansys Fluent, could anyone share very useful training resources (books, videos etc.) that can assist me to smoothly kick-start this project?

I would like to know which of these reactors is expected to record the highest conversion for CSTR and batch reactor when both reactors are assumed to have a similar volume, geometry, operating condition, and stirring rate (if possible do provide supporting resource/reference).

Thank you as you share your experience.

I would like to get the concept of what it is all about and relevant supporting materials would be appreciated. Thanks to you all.

Hello researchers,

I'm doing a gasification simulation, the problem I'm having is finding an equation that describes the pyrolysis reaction kinetics of the biomass I'm working on. Please give me your opinion on this matter.

Thanks

I want to model biomass pyrolysis by the following reaction set:

Biomass = CO

Biomass = CO2

Biomass = H2

Biomass = H2O

Biomass = CH4

where Biomass is a non-conventional solid, in a RCSTR reactor. Can I do it and if I can how?

I need to mention that Biomass contains C,H,O according to its ultimate analysis.

I also attach the model that I've tried to setup to solve this problem. If anyone can help me, I would appreciate it.

Thank you in advance for your help.

I am considering methods to analyze the reaction kinetics of conversion reactions in aqueous medium. I know pH-stat titration can monitor it. Can IES be used the same way?

A solution having 2 compounds in it whose degradation is measured by checking absorbance. How can we measure absorbance of such a solution when lambda max is different for these 2 compounds?

For example, let's say if I design a

**conversion reactor**and give**inlet temperature,pressure,composition and reaction kinetics**then**Hysys**will show me the**outlet conditions**. It doesn't,however,show**the process**or how it got the results i.e**calculations**.It will be very helpful if you can answer this.

Thanks in advance.

When there is the Thiele modulus and the effectiveness factor to determine the pore resistance in catalysts, why do we need the Wagner modulus?

I search for a long time, only the reaction mechanism of RDX is listed on articles, however, is there a archived chemkin format file for the RDX reaction mechanism? as well as the thermo and transport data?

Any help or information will be appreciated.

I added the equation about it here.

I'm stopped since I failed to calculate wave impedence.

Especially, relative permittivity and relative permeability are big obstacles for me to solve.

What I'd like you to do for me is not let me know how to calculate easily(of course, I'd thank you for it),

it would be even very thankful to you if you share me with books addressing this, with book names together.

Thank you for reading my question. I hope you help me.

Hello All,

In order to make some calcium test devices, we will be needing to expose calcium pads (100 nm of thickness) to nitrogen atmosphere. We do not expect the exposure time to be more than a few minutes. Twenty minutes could be considered a safe upper limit.

I am wondering if anyone who has had a similar experience can tell me if this would lead to severe degradation of the calcium pads.

The oxygen content inside the glovebox is assumed to be less than 1000 ppm. I have reaction rate data for oxygen, and I can take care of that. I'm mostly concerned with reaction with nitrogen itself, for which I have not been able to find any reaction rate data.

Thanks,

Pouyan

Hi every one,

I'm working on developing a reaction kinetics for a set of 100 sub reactions. most of the elementary reactions has a clear k value but some of the acidic reactions have just the PKa value. How can I involve these reactions in my overall kinetic equations?

should I find k+ and k- (forward and reverse reaction k values) for these reactions?

Thanks

Hi every one,

I'm working on developing a reaction kinetics for a set of 100 sub reactions. most of the elementary reactions has a clear k value but some of the acidic reactions have just the PKa value. How can I involve these reactions in my overall kinetic equations?

should I find k+ and k- (forward and reverse reaction k values) for these reactions?

Thanks

I just want to perform the kinetic study of pollutant degradation by H2O2. But how can we stop the H2O2 reaction after the sample collection at different time Intervals before the test of the collected samples. Please suggest me any possible way to stop the H2O2 reaction after the samples collection.

I am trying to calculate the reaction rate constants (k) of chemicals and this is usually given in units of cm^3/mol*s or a variation thereof. However I came across a few papers that gives it in 1/Torr*s and I am not sure how to convert it to cm^3/mol*s for comparison with other reaction rates.

What are the kinetics of the reaction between aqueous solution of ferrous chloride and chlorine gas, can it be considered as a diffusion process with chemical reaction?

Hi,

I'm doing a group research project at university and we are struggling to find reaction/kinetic data for very-long-chain fatty acids (C-18 to C-24), and was wondering if anyone would be able to point me in the right direction?

Trawling through online articles is currently leading me round in circles and so far no book I have access to has been of use.

I am unable to carry out an experiment to obtain the data myself, hence why I have been looking elsewhere.

Thank you in advance for any help!

I just need the k-constants or values that will help me model the reaction

For my adsorption system I need to calculate thermodynamic parameters. For the study I used 3 equations

1. ∆G = −RT lnb (b is the Langmuir isotherm constant)

2. ∆G = ∆H −T∆S

3. ln b=- (∆H/RT)+(∆S/R)

When I plot the graph of ln b Vs 1/T. I got a positive gradient and a negative intercept. Giving a negative ∆H, ∆G, and negative ∆S.

Is it possible to have such values and a graph and is the graph acceptable with a positive gradient?.

Hey chemistry community :)

I want to measure how fast radicals are produced by the reaction APS and TEMED. Does anyone know how one could do this? Is UV/Vis possible?

Thank you

How can I calculate the activation energy and frequency factor of a reaction where the reaction rate increases with temperature until a specific temperature and after that the reaction rate reduces with rise in temperature?

I believe in a normal reaction case (i.e., reaction rate is proportional to temperature), the activation energy and frequency factor can be calculated from the slope and intercept value of a line plotted with time vs ln (slope of fitting equation), using Arrhenius law.

I am looking forward to your suggestions.

Is there any chance for a metal hydride reaction to slow down over a specific temperature?

Hello,

Happy new year. I'm working on the synthesis of polymers using ultrasound assisted approach.

My question is how is possible to study the reaction kinetics and thermodynamics ?

Many thanks for your suggestions

This question is a bit complicated, but I will try to summarize succintly:

I have reaction kinetics data (order of reaction, reaction rate constant, and activation energy) for the degradation reaction of single CdSe/CdS core/shell quantum dots in air. I would like to use this information to determine (a) specific chemical reaction(s) associated with the degradation process. The system is a CdS surface with oleic acid passivating ligands. The surface is (presumably) reacting with either oxygen or water in the air. Is there a software package that will allow me to model such a reaction? Do I need to find a theorist who can help?

Thanks for any suggestions!

I would like to know if anyone knows how to plot the surface ([B] vs t vs k1/k2 ) as a numerical solution of the kinetic model of the mechanism A -> B -> C, specifically for the concentration profile of the intermediate specie [B], using any MATLAB ODE solver.

I wanted to do a pH-stat experiment for lipase reaction kinetics, but I am finding the auto-titrators with pH-stat capabilities exceedingly expensive (~ 10000$? , I also take suggestions on more affordable models) .

I have been thinking of building my own using an Arduino (or similar) together with kits from Atlas scientific, but I am afraid that the flow rates for their pump kit might be to high for the pH-stat type experiments. Anyone on RG that has successfully built such a device?

recently, I was trying to get a kinetic view of the reaction rate within the biofilm and on electrode surface.

Based on Nicholson's equation, k0 of a redox reaction on electrode surface could be calculated based on CV method, and the k0 will be in a unit of

*.***cm/s**But for the biofilm, I read some papers using Raman spectroscopy to determine the rate constant and they get an apparent rate constant in the unit of

*. see the attached paper.***s-1**My question is is there any equation to convert the unit from

**to***s-1***? or another way to compare the flux (mmol/cm2/s) across the biofilm and electrode surface?***cm/s*In order to calculate the equilibrium pressure in the reaction kinetics for hydrogen storage in hydrides. I've found in letterature a polynomial expression of it in terms of (H/M) or (X). Please who can help me in this issue? So, I'm looking for the expression of (H/M).

I am designing a CSTR reactor for the cativa process using methanol carbonylation reaction to methyl formate/acetic acid but unable to find the rate determining step for the methanol carbonylation and reaction kinetic data. so, i m unable to design reactor. If anyone has kinetic data so kindly share with me.

I am designing a CSTR reactor for the cativa process using methanol carbonylation reaction to methyl formate/acetic acid but unable to find the rate determining step for the methanol carbonylation and reaction kinetic data. so, i m unable to design reactor. If anyone has kinetic data so kindly share with me.

I want to get the Km and Kcat of enzyme E3.

However its substrate C is very unstable for its R-S conformation exchange.

I have found the following rate kinetics for the following reaction. As you see, the reaction is reversible one in which Xylene disproportionates and toluene and trimethylbenzene form ( r is reaction rate for xylene ).

If in the reactor, the reaction occurs in reverse direction such as toluene and TMB react and form Xylene, is it possible to use the same rate kinetics? Should I change some parameters? or this rate is OK for both reaction's direction?

( work done by André Luís Alberton )

Thanks in advance.

Hello everyone,

I aim to insert reaction kinetics in a stripping column (RadFrac) I'm currently working at. My problem is the kinetic model I would like to implement uses rate constants which are not fitted with the temperature, as usual, but instead they use pH. For instance, an expression of this kind:

k = a + b*pH + c*pH^2

How could I overcome this difficulty?

Thank you very much.

I need the dimensions of tatoray reactor such as diameter, height and so on. Could you please provide me with related information. Thank you in advance.

We are doing polymerization reactions with Salen Mn and Zn diketiminate complexes, working on reaction kinetics.

Hi,

I have a question regarding modified Arrhenius equation:

k=AT

^{b}exp−^{E/RT}Does anyone knows how to choose the term temperature exponent 'b' for a specific reaction. The only thing I can find in literature is that it is often taken zero. But I can see it has effect on reaction results but could not find any literature to see how to choose it.

Many thanks in advance!

I want to reduce NaBO2 to NaBH4 on a catalyst (electrode). Kindly provide me suggestions of how can I confirm that the reduction of NaBO2 to NaBH4 is taking place or not?

I have worked on Kinetic parameters of rechargeable Nickel Metal-hydride batteries and i have had a question about Avrami kinetic models,

In constant voltage discharge of a cell, if the shape of the curve looks like diffusion control models and the value of "n" in Avarami model is equal to 1, how can we analyze the results? does it mean diffusion of the reaction species control the reaction kinetic?
Best Regards

I would like to find a conclusive research paper(s) which details all the reaction rate constants for the Cativa process / methanol carbonylation in a table.

I have looked through this paper:

Promotion of Iridium-Catalyzed Methanol Carbonylation: Mechanistic Studies of the Cativa Process

However it does not seem to provide all the rate constants.

Any help much appreciated!

While studying the effect of residence time on reactants conversion to product, it was noticed that after some time the conversion is no longer increasing, but remain almost stable. Generally, it is known that reaction rate decrease with time, but this may not be a sufficient reason for the observed trend. Kinetically/mass transfer limited phenomenon may not also apply here considering that the reaction is kinetically limited in the initial stage, so in theory it can not change to mass transfer later on. A possible reason but not sure about is that the reaction order or mechanism could change after sometime.

Why the first order kinetics used in polyphenol degradation, despite the fact that in some cases the decrease of concentration is linear?

I had measured the CV of

**0.1 M aniline in 1 M perchloric acid**and I have got CV which I am going to attach from this file but the whole scenario is not clear to me about this CV what information from the peaks we are getting please elaborate if any body is familiar with this...1. I want to know about every peaks.

2. reaction kinetics.

Hi

if anyone has worked on modeling of Thermochemical heat storage by metallic oxides, please contact. i need help for modeling reaction kinetics of a reversible redox reaction. Its urgent. Thanks alot..!

usually in calculating first and second order kinetics, we use the value of concentration. but if i want to calculate the reaction kinetics by using using flourescence intensity, what will be the equation?

A solution of A is mixed with an equal volume of solution B containing the same number of moles and the reaction A + B ↔ C occurs. At the end of 1 hour A is 75% reacted. How much of A will be left un-reacted at the end of 2 hours if the reaction is first-order in A and zero order in B?

We have been supplied the standard first order rate equation.

I am moderately familiar with enzyme kinetics. I understand this is a simple matter of using the formula, however I cannot for the life of me figure it out. Step by step details of how each part of the question is worked out, and why it is done that way, would be absolutely amazing!

Thank you,

Jack

I am having trouble working out the basics of enzymes kinetics. I understand the formulas, and what they mean, however applying data to the equations and returning a meaningful answer is something I'm struggling with. Here's an example of a question I can't figure out:

A solution of A is mixed with an equal volume of solution B containing the same number of moles and the reaction A + B ↔ C occurs. At the end of 1 hour A is 75% reacted. How much of A will be left un-reacted at the end of 2 hours if the reaction is:

A) First order in Both A and B

B) Zero order in both A and B

For instance, I know the answer to B) should be zero are changing, as it is relative on the concentration of the enzyme. I have figured this out from notes, however I don't quite

*understand it*.If someone could explain how to apply the basic rate equation formulas to this question, and why you do what etc, i'd greatly appreciate it.

Thank you all for you your time :)

Probable major and minor product and suitable reagent and catalyst for chlorination of the 2,5 dimethoxy amphetamine .

In estimation of total phenol and flavnoids per eg.

If Conc . 1000 (mg/l) Abs 1.2

Then If conc. 500(mg/l) Abs. 0.6? Is that compulsory?

If the concentration is half then Absorbance should be half?

In many research articles it does not follow this trend.. There is decrements in absorbance ,but it is not directly proportional.

So how should be the actual curve for total phenols and flavnoids

Greetings,

I have questions about the units for DR and Temkin Isotherms. I read a couple articles and I don't find a consensus about the units, especially for qt and Ce. I believe that the unit for Ce on Temkin Isotherms need to be L g-1 because of "k" (I found many authors saying that unit for "k" for Temkin is g L-1), but the units for qt it's a little bit vague for me (Needs to be mg L-1 because all my isotherm and kinetic studies use mg L-1, or they are models with different qt units?).

Thank you so much

I have a reaction(bi-molecular) for which I have formed reaction complex, transition state and product. Now I want to calculate the rate constant for the reaction as well as the quantity of the product forms (I know the Initial amount of the reactants). I have performed all the calculations using Gaussian 09 program.

Working on designing the Cativa process but can not figure out the kinetics, really would appreciate the help.

Actually trying to model reaction kinetics of polyethylene in RCSTR, but have been having mass balance error. Really do not know what to do.

We are analyzing an exothermic reaction that deals with the addition of mCPBA. But during addition, it yields an endothermic curve, followed by exothermic curve.

However when we take the conversion values with respect to addition, we obtain negative conversion values for the addition of mCPBA. We obtain positive conversion values After the addition of mCPBA.

As per the normal scenario we used to obtain positive conversion values for an exothermic reaction when the heat generates, thermal conversion happens.

I need some suggestions on how to incorporate that negative conversion values in my calculations. Please refer to attachments.

I obtained the heat generation data (Qrx) from RC1e Mettler Toledo with the integration with respect to baseline and reaction limits.

I extracted the individual thermo-kinetics data with time variation of two seconds, but we used an approach (refer attachment) to match the Qrx value of all the time intervals to the RC1e given Qrx and, we tried to plot the Qrx value of Excel, with respect to time but we are not obtaining the exact curve given by Mettler Toledo RC1e.

Can anyone suggest to me how to find the calculation (Qrx) of integration and how to obtain the Qrx curve as similar to RC1e Qr curve?

I have extracted some kinetics data Reaction calorimeter RC1e, and as I know the reaction rate,order,rate constant I can evaluate the total energy generation, corresponding to that I can estimate cooling capacity required?

But I was in a confusion, which reactor I should recommend to plant scale up.

As per my knowledge, I always recommend semi-Batch reactor because we can control the heat generation with the dosing, so we can escape thermal runaway scenario.A rational choice between a variety of requires knowledge of reaction kinetics,thermodynamics and property of the reaction mixture through out the system.

Thus anyone please give me a proper clarification regarding aforementioned aspects.

Dear sir,

We are performing a reaction which involves nitration of 4-Hydroxy-2-trifluoromethyl pyridine in the Conc.sulfuric acid medium& fuming nitric acid added successively at 0°C and heated to 80°C to form compound 2-nitro-4-trifluoromethyl-phenol.

For the scheme please refer to attachment "kinetics.png".

I have completed with finding the rate constant and reaction order,However I am not able to estimate Enthalpy of the reaction(-ΔHr) to find the total heat production or heat generation as mentioned in the equations below.

I have extracted the data from Mettler toledo RC1e, and I would like to mention that I had summed up the individual Qr,so i got the heat generation in the Watts(W), and I multiplied that total watts with the corresponding time to convert into Kilo-joules.

The total heat generated Qrx (kilo-joules) is not matching with the Corresponding RC1e Heat generation value.

And I want to plot those individual qr values w.r.t time to generate Qrx vs time Curve.

Hence I would request your advice on how to go forward.

Further I would like to request from you any other similar case study which you can share.

Please refer to the excel sheet and final report attached for further clarification.

Kind Regards,

Raghu Perumalla,

Process Safety Engineer,

Scale Up Facility,

TCG Lifesciences Pvt Ltd,

Kolkata,India.

Arjun Chaudhuri,

M.Sc ( Bio Chemical Engineering )

Technical University of Delft,

The Netherlands.

The kinetics of reduction can be expressed by Arrhenius equation:

r=kexp(-E/RT) [CH4] , mol/m3.s

I am interested to know the kinetics parameters of K and E for the reduction of iron oxides with methane for mathematical simulations.

Dear all.

I have some confusion, I read an article talk about the effects of nostoichimetric on catalytic activity of La

_{0.9}MnO_{3}the auther explan the increase of catalytic activity of LaMnO

_{3}with increasing of Mn content (La_{0.9}MnO_{3}) (for NO oxidation) is due to increase of Mn4+/Mn3+ ratiowhile another investigation deduced that the catalytic activity of LaMnO

_{3}( LaMn_{0.9}O_{3}) (for methane combustion) is increase with increasing of La contentmy question is how to explan the increase of catalytic activity with increasing of La content ?

VO+ 1/2 O

_{2}gives VO_{2}. I need to find out the log K of this reaction?. Can someone help?Hello how best would I electro-deposit ZnTe onto a metal Oxide with good adherence. Also the sulfuric acid used in dissolving the ZnTe seems to etch of the ITO glass substrate during deposition. How best can I do this deposition without etching the substrate as well

I'm constructing process flow of methane nonoxidative aromatization following the paper which describes kinetics. "Kinetics of Methane Nonoxidative Aromatization over Ru−Mo/HZSM-5 Catalyst" "http://pubs.acs.org/doi/abs/10.1021/ie030044r"

I instlalled kinetic of reaction (9) which is described by equation (15) and it worked successfully, but adding equilibrium condition, reaction (11) and equation (17), it failed with message "The Aspen Plus calculation engine has unexpectedly shut down." I'm not sure and I could not find remedy to fix it.

I would really appreciate any information related.