Scope | User Contributions | Rate Constant Definitions | Knows Issues and Tips | Disclaimer | Credits
This database of second-order rate constants (all given in units of M-1
) for oxidants used for in situ chemical oxidation (ISCO) is a by-product of research in this area by the group of Paul Tratnyek
. An overview of our work on ISCO is here
. For general background on ISCO, try this
While there are other on-line databases containing rate constants, none of them are focused on environmentally relevent reactants. The IscoKin database is intended to include second-order rate constants for environmental contaminants reacting with environmentally-relevant oxidants (see below). It also includes data for some compounds that are not "environmentally-relevant" per se, but that represent structural analogs to environmental contaminants and therefore might be useful, for example, in developing quantitative structure activity relationships.
At this time, the oxidants included in IscoKin are hydroxyl radical (OH), permanganate (MnO4), sulfate radical anion (SO4), carbonate radical anion (CO3), ozone (O3), chlorine dioxide (ClO2), and singlet oxygen (1O2). Data on the first four of these oxidants are much more complete than the others, but we hope this will even out as new data are added.
The IscoKin database contains mainly second-order rate constants taken from the peer-reviewed scientific literature. However, rate data from the "gray" literature or even "personal communications" (i.e., as yet unpublished results) are welcome as long as they are of high quality and come from a traceable source.
Pseudo-first-order rate constants are not in the scope of IscoKin.
Most other on-line databases of rate constants (or chemical property data, in general) are not actively maintained and do not provide a direct way for users to submit new information. The IscoKin database allows users to submit data directly to the database with minimal oversight by the site admistrators. In that sense, it reflects some of the philosophy and functionality of a "wiki
Submitting new data involves four steps: (i) register
as a user, if you haven't already; (ii) login
, (iii) go to the add
page and determine if your compound is already in the database, (iv) add your data. Your individual data will be available immediately, but will be highlighted in red to indicate that they are newly submitted. The administrators will review it and if they find no obvious errors they will approve the new entry. At that point the red highlight will go away and the database will begin using the new value in its calculation of representative values (see below).
You can not edit previously submitted data. If you would like to submit corrections to existing data please e-mail the IscoKin administrators
Representative and Average Rate Constants:
IscoKin includes three types of second-order rate constants: (i) individual measured values, (ii) recommended values, and (iii) ad hov averages of the individual measured values.
Individual measured values
are values taken directly from a single source. They may have been modified from the original source if a second-order rate constant was calculated from a first-order rate constant, or if the original source published the rate constant in units other than M-1
are typically are the average of the rate constants obtained between a temperature range of 20-30 ºC and a pH range of 4-10. When a temperature or pH value was not available, the associated rate constants usually were included in the average. Rate constants that were obvious outliers were not included. For iogenic compounds, we averaged the rate constants within the pH range where the compounds are at least 90% protonated or deprotonated. Not all representative values were determined according to this formula, but for consistency, we are working on rectifying this as time permits.
Ad hoc average values
are values you can calculate by selecting the individual measured values that meet your own particular needs. For example, this tool allows you to average values within a smaller temperature or pH range than those used for the recommended values. In addition, it allows you to incorporate newly added data that has not yet been approved by the administrators.
Known issues and tips:
- Some browsers (mainly older versions of Explorer) do not initiate a search when you type "return" or "enter"; instead you will have to click on the "Search" button provided on the screen. With these browsers, "return" clears the search field.
- The database is currently case-sensitive; so if searching with a lowercase name did not yield results, try capitalizing the first letter (or vise versa).
- When you select "view all" for a particular compound, you will see all entries for that compound. If you only chose one oxidant (such as OH) and the entry is for a different oxidant, the field for OH will be blank, but you will see the other pertinent information (reference, pH, etc) for that entry.
The information IscoKin contains is not perfectly accurate or complete, so beware! We do not recommend that you use numbers directly from this database for critical applications: you should track down the primary sources and use them as the ultimate source of the data, conditions, and other caveats. Obviously, we do not accept any responsibility for what anyone does with information obtained from this database.
This database was developed with funding by the Strategic Environmental Research and Development Program (SERDP
) under Project CU-1289. This database has not been subject to review by SERDP and therefore does not necessarily reflect their views and no official endorsement should be inferred.
Kahlie Langley wrote the the code that runs the database while she was was a participant in the Saturday Acadmey's Apprenticeships in Science and Engineering Program (ASE