{"id":9771,"date":"2020-04-01T14:49:56","date_gmt":"2020-04-01T12:49:56","guid":{"rendered":"https:\/\/kluthe.com\/magazin\/?p=9771"},"modified":"2025-07-04T10:33:05","modified_gmt":"2025-07-04T08:33:05","slug":"properties-of-solvents","status":"publish","type":"post","link":"https:\/\/kluthe.com\/magazin\/en\/properties-of-solvents\/","title":{"rendered":"Properties of Solvents"},"content":{"rendered":"

In chemistry, a solvent is a substance that enables the uniform distribution of particles from another substance within a mixture. In a homogeneous solution, the dispersing agent is the component makes up the larger amount. In surface technology, liquid solvents<\/a> are primarily used for cleaning tasks and for handling process chemicals. For effective application, the properties of the\u00a0liquid medium and the solute must be compatible\u2014meaning they need to be carefully matched.<\/strong><\/p>\n

Polar and Non-Polar Solvents<\/h2>\n

One of the most important characteristics for assessing the suitability of a solvent is polarity. Molecules, which are composed of atoms, consist of a positively charged nucleus and a surrounding shell of negatively charged electrons. Whether a molecule is polar or non-polar depends on how these electrons are distributed. If the electrons are evenly distributed, the molecule is non-polar. If the electrons are distributed asymmetrically, the molecule has a partial positive and a partial negative region\u2014making it a dipole. Substances made of such molecules are called polar.<\/p>\n

\"Water
\u00a9 Alexstar \u2013 stock.adobe.com<\/figcaption><\/figure>\n

Water is the most common example of a polar solvent. Its molecules form a triangular structure with the large oxygen atom creating a negative pole and the smaller hydrogen atoms forming a positive pole. Molecules of other polar substances\u2014such as vinegar, alcohol, salts, acids, or sugar\u2014align themselves accordingly, which leads to uniform distribution in water.<\/p>\n

\"Purging<\/a><\/p>\n

When you attempt to mix a non-polar substance with a polar liquid, the polar molecules attract each other and exclude the non-polar substance, causing it to separate into a distinct phase. On the other hand, non-polar substances mix easily with one another and form homogeneous solutions.<\/p>\n

These basic interactions form the foundation for selecting appropriate rinsing agents and paint formulations in surface technology<\/a>.<\/p>\n

Evaporation Number of Solvents<\/h2>\n

At the surface of a liquid, molecules are constantly entering the surrounding gas phase\u2014typically air. Some return to the liquid, but as long as more molecules leave than return, the liquid gradually evaporates. The volume that has left the liquid has turned into vapor.<\/p>\n

\"Solvent-Based<\/a><\/p>\n

In a sealed container, such as a paint can, an equilibrium eventually develops between the liquid and vapor phases. This equilibrium depends on temperature: the higher the temperature, the more molecules exist in the vapor phase.<\/p>\n

Evaporation Behavior<\/h2>\n

If the space above the liquid is large enough, or if vapor escapes freely, the liquid will eventually fully evaporate. The time required depends on the liquid’s physical properties, ambient temperature, humidity, and air pressure. If these last three factors are kept constant, the evaporation rates of different liquids can be compared.<\/p>\n

\n

Diethyl ether is often used as a reference substance due to its rapid evaporation.<\/p>\n<\/blockquote>\n

To evaluate another solvent’s evaporation behavior, the time it takes to evaporate a specific quantity is divided by the time it takes for the same amount of diethyl ether to evaporate under the same conditions. The result is the evaporation number. The higher the number, the slower the evaporation.<\/p>\n

Examples of Evaporation Numbers<\/h3>\n