Dehydrating

Dehydrating is the process of removing water from a substance. In chemistry, dehydration refers to reactions that eliminate water from reactants, forming new bonds. In everyday contexts, dehydration commonly describes the drying or desiccation of materials, or the loss of body water in living organisms.

In chemistry, dehydration reactions remove H2O and are used to form alkenes from alcohols (for example, ethanol to ethene with acid catalysis) or to join carboxylic acids to form anhydrides. Dehydration can also describe drying of compounds to drive off water, enabling solid-state synthesis and improved stability.

Dehydrating foods and other materials is used to preserve perishables and reduce weight. Common methods include sun drying, hot air or vacuum drying, oven drying, and freeze-drying (lyophilization). Desiccants such as silica gel also remove moisture. Industrial dehydration includes drying of chemicals, grains, and pharmaceutical products.

Biological dehydration occurs when an organism loses more water than it takes in, leading to reduced tissue fluid, impaired function, and potentially life-threatening shock. In humans, causes include insufficient fluid intake, sweating, diarrhea, or vomiting. Symptoms range from thirst and dry skin to dizziness and confusion; severe dehydration requires medical care and rehydration with electrolytes.