Lab Solvents is an app that provides a reference list of solvents, with structures, names, physical properties, and auxiliary information about their health, safety and environmental impact. The app is inspired by the earlier Green Solvents app, and provides more information, and more functionality for browsing, filtering and sorting content. Health, safety and environmental ("greenness") information has been collected from two sources: the American Chemical Society Green Chemical Institute pharmaceutical roundtable report on green solvents, and the GlaxoSmithKline Solvent Selection Guide. The app runs on Android-based devices, and is available for free on Google Play.
Most interaction with the app takes place on the main screen:
The main screen is divided up into two main parts: the control block and the solvent list. The control block provides actions buttons and methods for altering the display of solvents, while the solvent list displays the structures of solvents, and can be browsed by swiping up and down.
Tapping on any of the solvent icons brings up the corresponding detail view, for example benzene.
The first block shows the chemical structure of the solvent, followed by other information as available. Benzene is categorised as an aromatic solvent, which is indicated. This classification corresponds to the filter icons, which are explained later.
Melting point, boiling point and density are displayed, when available. The molecular formula and weight are shown, as is a chemical abstracts registration number (CASRN), when available. Many of the compounds have a corresponding ChemSpider identification number, which can be clicked on to visit the corresponding ChemSpider page using the mobile browser.
For most solvents, there is data for either ACS Green Chemical Institute or GSK Solvent Selection Guide properties, or both. Both of these classification schemes use selected metrics for the degree to which a solvent is problematic from the perspective of lab safety, human health due to exposure, or environmental malignancy. Each of these properties has been rated on a scale from 1 to 10. The Lab Solvents app represents these properties as colour-coded histograms, which make it easy to spot the properties at a glance, and also convey the impression that these numbers are estimates, rather than absolute properties. Ratings in the green region (to the left) suggest that the solvent is relatively innocuous, while ratings in the red region (to the right) suggest that it is particularly problematic, i.e. dangerous, toxic, or harmful to the environment.
The control block at the top of the screen presents a number of widgets which can be used to control the solvents that are displayed in the list underneath.
Selecting the text box and entering a search term will cause the solvent list to be restricted to showing only those solvents whose names contain the indicated text (e.g. searching for "zene" will match Benzene, Benzyl alcohol, etc.). The text can also be used to find solvents by CAS number or ChemSpider ID.
Pressing the button on the top right that is initially labelled similar structure will bring up the structure editor, and allow a chemical structure to be sketched (or pasted from the clipboard). Applying the structure will cause the list to be sorted by structural similarity.
For example, providing the structure of benzofuran as a reference causes the display to be updated as:
Note that the first three structures consist of a benzene ring and an ether or alcohol substituent, which have the highest structural similarity to the query, followed by a series of less similar benzene-derived structures.
The control block contains a row of filter icons, each with an indicator symbol. Pressing any of these buttons will allow the list of filters to be filtered to include or exclude solvents with this property. Most of the filters refer to the category of the solvent, and the rest refer to safety, health and environment characteristics.
These icons are also represented on the solvent display buttons. Benzene, for example:
The three icons on the right indicate that the solvent is in the aromatic class, is dangerous, and presents a health hazard.
The Lab Solvents app provides a very convenient and useful reference source for common lab solvents. The app can be consulted for reference information such as physical properties, health, safety and environmental effects, and links to external sources. Solvents can be browsed by categories or properties, and searched by text or ranked by structural similarity.