Search results
Results From The WOW.Com Content Network
The chloroform molecule can be viewed as a methane molecule with three hydrogen atoms replaced with three chlorine atoms, leaving a single hydrogen atom. The name "chloroform" is a portmanteau of terchloride (tertiary chloride, a trichloride) and formyle, an obsolete name for the methylylidene radical (CH) derived from formic acid. [citation ...
In chemistry, the haloform reaction (also referred to as the Lieben haloform reaction) is a chemical reaction in which a haloform (CHX 3, where X is a halogen) is produced by the exhaustive halogenation of an acetyl group (R−C(=O)CH 3, where R can be either a hydrogen atom, an alkyl or an aryl group), in the presence of a base.
Sample preparation for PI includes first ensuring the sample is in the gas phase. PI ionizes molecules by exciting the sample molecules with photons of light. This method only works if the sample and other components in the gas phase are excited by different wavelengths of light. It is important when preparing the sample, or photon source, that ...
Gas properties Std enthalpy change of formation, Δ f H o gas –103.18 kJ/mol Standard molar entropy, S o gas: 295.6 J/(mol K) at 25 °C Heat capacity, c p: 65.33 J/(mol K) at 25 °C van der Waals' constants [4] a = 1537 L 2 kPa/mol 2 b = 0.1022 liter per mole
They convert polar compounds into less polar more volatile derivatives. In this way, chloroformates enable relatively simple transformation of large array of metabolites (aminoacids, amines, carboxylic acids, phenols) for analysis by gas chromatography / mass spectrometry. [1]
Preparation. Methyl chloroformate can be synthesized using anhydrous methanol and phosgene. [2] COCl 2 + CH 3 OH → ClC(O)OCH 3 + HCl. Properties.
Benzyl chloroformate is commonly used in organic synthesis for the introduction of the benzyloxycarbonyl (formerly called carboxybenzyl) protecting group for amines.The protecting group is abbreviated Cbz or Z (in honor of discoverer Zervas), hence the alternative shorthand designation for benzyl chloroformate as Cbz-Cl or Z-Cl.
For Salkowski test's procedure one needs a sample, that is to be tested for sterols, as well as chloroform and concentrated sulfuric acid that represent Salkowski's reagent. Usually the solution of chloroform and the sample is prepared first and later treated with concentrated sulfuric (VI) acid. After that the whole solution needs to be shaken ...