Knowledge of physical properties is essential for the design of innovative chemical products and processes. Very often, in the early stages of a product or process design, we do not know the physical properties of the chemicals we are tasked to work with. Often, the only information we have is the chemicals' molecular structures. Physical property estimation techniques are thus often used to provide these needed values.
Group-contribution and equation-based estimation techniques are currently two of the commonly used methods for generating physical property estimates. Group-contribution based techniques take a chemical's molecular structure, dissects it into a set of groups, retrieves a numerical contribution for each group, and finally combines these contributions into a property estimate. Equation-based techniques typically take properties estimated by group-contribution techcniques and combine them in equations to predict other physical properties.
View the instructional video: Video Link
To estimate the physical properties of chemical, begin by drawing the chemical's molecular structure in the editor to the right. (Press the editor's demo button to view a short video explaining the editor's operation.) Once you have drawn the molecular structure, press the 'Get Estimates' button in the sections below. The entered structure will be sent to a WebServer Edition of Cranium running on the internet. Cranium will use group-contribution and equation-based techniques to generate physical properties estimates that will be returned to this webpage and shown below. (Note that the estimation process may take several seconds to complete depending upon the complexity of your molecular structure.)
Press the 'Get Estimates' button below to instruct the Web Server Edition of Cranium to estimate a set of constant-valued physical properties. This webpage will retrieve the molecular structure from the editor above, generate a molfile from the structure, and send the file to Cranium. Cranium's group-contribution techniques will use the mol file to dissect the structure into groups and estimate the set of physical properties shown to the right.
| Physical property | Estimate | Technique | Units |
|---|
Select a temperature-dependent physical property, enter a range of temperature values, and press the 'Get Estimates' button below to instruct Cranium to generate estimates for the selected physical property. Estimates are shown in the table to the right and the graph below. Estimated values are shown as diamonds. The different colors denote different estimation techniques.
| Estimated Values (diamonds) | ||
|---|---|---|
| Temperature | Estimate | Technique |
Select a temperature-and-pressure-dependent physical property, select a fixed state variable, either temperature or pressure, enter a range of temperature or pressure values, and press the 'Get Estimates' button to instruct Cranium to generate estimates for the selected physical property. Estimates are shown in the table to the right and the graph below. In the graph, estimated values are shown as diamonds. The different colors denote different techniques.
| Estimated Values (diamonds) | |||
|---|---|---|---|
| Temp | Pres | Estimate | Technique |
The Get Estimates buttons above retrieve your input molecular structure, temperatures, and pressures, package these into a request string and then send it to an instance of our Cranium, Web Server Edition software product running on a Microsoft Azure virtual machine. Cranium processes the request - dissecting molecular structure and estimating physical properties. The resulting estimates are then sent back to this webpage for display.
Click here to learn more about how you can use our Cranium Web Server to distribute your company's physical property data, estimates, and knowledge throughout your organization or contact us for further details.