Millipore Sigma Vibrant Logo
 
Drying Agents
 

Laboratory Application Notes

Drying AgentBest Suited ForNot Suitable ForRegenerationApplication Notes
Aluminum Alcohols   Chemically active desiccant: regeneration not possible Must be activated with iodine or mercury (II) prior to use. Drying process involves formation of insoluble metal hydroxide and metal alcoholate. Distillation must be performed after drying.
Aluminum oxide Ethers and aliphatic, olefinic, aromatic, and halogenated hydrocarbons Compounds which contain epoxide, carbonyl ester or thio groups 170-250°C in a drying oven For dynamic drying of solvents in packed glass columns. Peroxides and traces of acid are also removed. Aluminum oxide used for removal of peroxides must not be regenerated.
Calcium Alcohols   Chemically active desiccant; regeneration not possible Drying process involves formation of insoluble metal hydroxide and metal alcoholate. Distillation must be performed after drying.
Calcium chloride Acetone, ethers, many esters, aliphatic, olefinic, aromatic and halogenated hydrocarbons, neutral gases Ammonia, amines, alcohols, aldehydes, phenols, some esters, ketones 250°C in a drying oven Appropriate for drying of liquids and filling of drying tubes. Not suitable for drying of fast-flowing gases.
Calcium hydride Gases, organic solvents including ketones and esters Compounds with active hydrogen, ammonia, alcohols Chemically active desiccant; regeneration not possible Highly active drying agent which does not decrease in activity during the drying process. Reacts vigorously with water, releasing hydrogen. Must be used in a fume hood.
Calcium oxide Neutral and basic gases, amines, alcohols, ethers Acids, acid derivatives, aldehydes, ketones, esters 1000°C Basic drying agent most suitable for dehydrating low-boiling alcohols, ammonia, and amines.
Calcium sulfate Universal applications   190-230°C in a drying oven Especially suitable for drying gases containing small quantities of organic compounds that have to be analyzed, as these will not be absorbed by calcium sulfate. Not effective at temperatures above 80°C.
Copper sulfate Alcohols, esters, low fatty acids Amines, nitriles, ammonia Above 50°C under vacuum Can be used as indicator: colorless anhydrous copper (II) sulfate will become blue as copper (II) sulfate pentahydrate.
Drierite Most gases and liquids Phosphates esters, acetone 200-225°C in a drying oven Stable drying agent with a neutral pH that is chemically inactive toward reagents other than water. Used in desiccators, Karl Fischer titrator drying tubes, packed drying towers, and in packets for storage and transport of electronics, footware, packaged foods, etc.
Magnesium Alcohols   Chemically active desiccant; regeneration not possible  
Magnesium oxide Alcohols, basic liquids, ammonia Acidic compounds 800°C Basic drying agent comparable to calcium oxide, but less effective.
Magnesium perchlorate Inert gases, air, ammonia Organic substances in which it is soluble 240°C under vacuum Explosion hazard when in contact with a reducing atmosphere, particularly in the presence of acids or compounds that can be hydrolyzed to form acids. May only be heated in vessels made on inorganic materials.
Magnesium sulfate Almost all compounds including acids, acid derivatives, aldehydes, esters and ketones.   200°C in a drying oven  
Molecular Sieves The application is dependent on the pore diameter, whide application for gases and liquids   300-350°C under vacuum or in a stream of dry inert gas, e.g., nitrogen, argon, etc. Click here to see "Molecular Sieve Applications by Type"
Potassium carbonate Ammonia, amines, acetone, nitriles, chlorinated hydrocarbons Acids, substances that react when exposed to dehydrating basic conditions 160°C in a drying oven A deliquescent drying agent for liquids.
Potassium hydroxide Basic liquids, inert and basic gases Acids, acid derivatives, phenols Chemically active desiccant; regeneration not possible Can also be usd to simultaneously absorb acid vapors. Not suitable for drying of fast-flowing gases.
Sicacide Sulfuric acid concentrate Air, inert neutral and acidic gases Unsaturated and other organic compounds, oxidizing gases (e.g., hydrogen sulfide, hydrogen iodide) Chemically active desiccant; regeneration not possible Sicacide is sulfuric acid with an indicator, immobilized on an inert solid support for easier handling than conventional concentrated sulfuric acid. Used in wash bottles for drying gases and in open dishes in desiccators.
Sicapent Phosphorus pentoxide Inert neutral and acidic gases, saturated aliphatic and aromatic hydrocarbons, nitriles, alkyl and aryl halides, carbon disulfide Alcohols, amines, acids, ketones, ethers, chlorinated and fluorinated hydrocarbons Chemically active desiccant; regeneration not possible Particularly suited for drying fast-flowing gases in drying tubes. Major advantage of Sicapent is that it remains free-flowing even after absorbing 100% of its weight in water.
Silica gel Practically all gases and liquids Alkaline liquids, hydrogen fluoride 150-250°CC in a drying oven Up to approximately 65°C performance is independent of temperature. Used frequently in desiccators, Karl Fischer titrator drying tubes, packed drying towers, and in packets for storage and transport of electronics, footware, packaged foods, etc.
Sodium Ethers, saturated aliphatic and aromatic hydrocarbons, tertiary amines Acids, acid derivatives, alcohols, aldehydes, ketones, alkyl and aryl halides Chemically active desiccant; regeneration not possible Use as sodium wire prepared directly prior to use by means of a sodium press, or as finely distributed sodium. Sodium reacts explosively with water. Sodium waste should be disposed of using a high-boiling alcohol.
Sodium hydroxide Basic liquids, inert and basic gases Acids, acid derivatives, phenols Chemically active desiccant; regeneration not possible. Can also be used to simultaneously absorb acid vapors. Not suitable for drying of fast-flowing gases. Slightly less effective than potassium hydroxide.
Sodium sulfate Alkyl and aryl halides, fatty acids, esters, aldehydes, ketones   150°C in a drying oven Used primarily for sensitive compounds. TracePur® grade suitable for removing residual water from extraction solvents used in environmental analysis without adding interfering contaminants.
t.h.e. Desiccant Practically all gases and liquids Alkaline liquids, hydrogen fluoride 120°C in a drying oven High-performance drying agent with high absorptive capacity provides drier samples faster than many other desiccant types. Maintains physical integrity even when fully hydrated.