Trimethylamine (TMA) is a compound with a strong fishy odor. It is found in fish, rotting fish products, and human sweat. It can cause bad breath and body odor.
| IUPAC Name | N,N-Dimethylmethanamine |
| Molecular Formula | C3H9N |
| CAS Number | 75-50-3 |
| Synonyms | TMA, Dimethylamine, Methyldimethylamine, N,N-Dimethylamine, Tertiary Methyamine, Tertiary Methylamine |
| InChI | InChI=1S/C3H9N/c1-4(2)3/h1-3H3 |
Trimethylamine Properties
Trimethylamine Formula
The chemical formula for Trimethylamine is C3H9N, which indicates that the molecule contains three carbon atoms, nine hydrogen atoms, and one nitrogen atom. The formula can be used to calculate the molecular weight and other properties of Trimethylamine.
Trimethylamine Molar Mass
The molar mass of TMA is 59.11 g/mol. This value is calculated by adding the atomic masses of all the atoms present in the molecule. The molar mass is an important parameter used in chemical calculations, including the determination of stoichiometry and the number of moles of a substance.
Trimethylamine Boiling Point
The boiling point of TMA is -6.9°C or 19.6°F. This is a relatively low boiling point, which means that the compound is volatile and can easily evaporate. TMA can be liquefied by applying pressure, and it is commonly used in gas form in various applications.
Trimethylamine Melting Point
The melting point of TMA is -117.3°C or -179.1°F. This is a very low melting point, which means that the compound is typically found in a liquid or gas state at room temperature. It can be solidified by cooling to temperatures below its melting point.
Trimethylamine Density g/mL
The density of TMA is 0.692 g/mL at room temperature. This value is used to determine the mass of TMA per unit volume. The density of the compound is relatively low compared to other liquids, which makes it less dense than water.
Trimethylamine Molecular Weight
The molecular weight of TMA is 59.11 g/mol. This value is the sum of the atomic weights of all the atoms in the molecule. The molecular weight is used to calculate the amount of a substance required for a specific chemical reaction or process.
Trimethylamine Structure
TMA has a pyramidal molecular geometry, with a trigonal pyramid shape around the nitrogen atom. The molecule has a central nitrogen atom, which is bonded to three methyl groups. The nitrogen atom has a lone pair of electrons, which contributes to the molecule’s characteristic odor.
Trimethylamine Solubility
TMA is soluble in water and organic solvents, including ethanol, ether, and acetone. The solubility of TMA in water is 1.8 g/100 mL at 25°C. The compound is highly soluble in polar solvents due to its polar nature, which makes it useful in various industrial applications.
| Appearance | Colorless gas with a strong, fishy odor |
| Specific Gravity | 0.692 at 25°C |
| Color | Colorless |
| Odor | Strong, fishy odor |
| Molar Mass | 59.11 g/mol |
| Density | 0.692 g/mL at 25°C |
| Melting Point | -117.3°C or -179.1°F |
| Boiling Point | -6.9°C or 19.6°F |
| Flash Point | -20°C |
| Water Solubility | Soluble |
| Solubility | Soluble in organic solvents |
| Vapour Pressure | 542 mmHg at 20°C |
| Vapour Density | 2.1 at 25°C |
| pKa | 9.79 |
| pH | Alkaline |
Trimethylamine Safety and Hazards
TMA poses several safety hazards, primarily due to its highly flammable nature and strong, fishy odor. It is classified as a hazardous substance by several regulatory bodies, including the US Environmental Protection Agency (EPA). Exposure to TMA can cause skin and eye irritation, respiratory problems, and nausea. It is also toxic when ingested or inhaled in large amounts. Proper precautions should be taken when handling TMA, including wearing appropriate protective equipment and ensuring proper ventilation. In case of exposure, immediate medical attention should be sought.
| Hazard Symbols | Flammable, Corrosive |
| Safety Description | Keep away from heat, sparks, and open flames. Avoid breathing gas. Use only with adequate ventilation. Wear appropriate protective equipment. |
| UN IDs | UN1083 |
| HS Code | 29211900 |
| Hazard Class | 2.1 – Flammable Gas |
| Packing Group | PG I |
| Toxicity | Toxic if ingested or inhaled in large amounts. Causes skin and eye irritation, respiratory problems, and nausea. |
Trimethylamine Synthesis Methods
There are several methods for synthesizing TMA, but the most common one is the reaction of formaldehyde with ammonium chloride in the presence of calcium hydroxide. We know this process as the Eschweiler-Clarke reaction.
Another method involves the reaction of dimethylamine with formaldehyde, followed by hydrogenation in the presence of a catalyst. We name this method the Leuckart-Wallach reaction.
The Frankland reaction produces TMA when sodium or potassium hydroxide is present during the reaction of ammonia with trimethyl borate.
One can produce TMA by reacting methyl iodide with ammonia and then reducing it with zinc dust. Chemists refer to this method as the Hofmann degradation.
Other less common methods for synthesizing TMA include the reaction of trimethyl phosphite with ammonia, the reaction of TMA oxide with acid, and the reaction of trimethylaluminum with ammonia.
Overall, the synthesis of TMA requires careful handling of reactive and potentially hazardous chemicals, as well as expertise in organic chemistry.
Trimethylamine Uses
TMA has several uses across a range of industries due to its unique chemical properties, including its strong and distinct odor. Here are some of the most common uses of TMA:
- Manufacturing of pesticides: Used in the production of several pesticides, including chlorpyrifos and diazinon.
- Organic synthesis: Organic chemists use TMA extensively in synthesizing quaternary ammonium salts, which find wide-ranging applications in various industries due to their exceptional properties.
- Gas treatment: Used to remove acid gases, such as carbon dioxide and hydrogen sulfide, from natural gas and petroleum products.
- Pharmaceutical industry: Used in the production of various pharmaceuticals, including the antidiabetic drug metformin and the local anesthetic procaine.
- Food industry: TMA causes the fishy odor found in certain seafood and adds flavor to some food products as a flavoring agent.
- Laboratory research: Also used in laboratory research, primarily in the study of protein structures.
Questions:
Q: What is the chemical formula for the conjugate acid of the base trimethylamine (CH3)3N?
A: The chemical formula for the conjugate acid of TMA is (CH3)3NH+.
Q: The pH of aqueous 0.050 M trimethylamine is 11.24. What is the Kb of this base?
A: The Kb of TMA can be calculated using the pH of its solution, which is 11.24. The Kb value is 1.8 x 10^-5.
Q: What is the initial concentration of trimethylamine in water?
A: The initial concentration of TMA in water depends on the specific solution being used. Without further information, it is impossible to determine the initial concentration.
Q: Is trimethylamine a strong base?
A: TMA is a weak base, as it only partially dissociates in aqueous solution.
Q: Is trimethylamine polar?
A: Yes, TMA is a polar molecule due to the presence of a nitrogen atom with a lone pair of electrons and the three methyl groups.
Q: Is trimethylamine an acid or a base?
A: TMA is a base, as it accepts a proton from an acid to form its conjugate acid.
Q: Does trimethylamine cause stress corrosion cracking in carbon steel?
A: Yes, TMA can cause stress corrosion cracking in carbon steel under certain conditions.
Q: What is trimethylamine used for in HPLC?
A: TMA is used as a mobile phase additive in HPLC to enhance peak shape and separation of basic compounds.
Q: Which is the stronger base, trimethylamine or pyridine?
A: Pyridine is a stronger base than TMA due to the nitrogen atom being part of an aromatic ring, which stabilizes the resulting conjugate acid.