What are the methods of chemical analysis? It has something to do with aromatics

Gas chromatography and liquid chromatography are generally used.

1.How can you tell the aromatic properties of a compound?

1.Aliphatic hydrocarbons: A general term for all hydrocarbons except aromatic hydrocarbons Alicyclic hydrocarbons:

The properties are different from aromatic hydrocarbons, and the rings that are very similar to aliphatic hydrocarbons are called alicyclic hydrocarbons. Aromatic hydrocarbons: abbreviated as "aromatic hydrocarbons", refer to hydrocarbons that contain a benzene ring structure in their molecules.

Aromatic compounds: Compounds that have a fragrance. The vast majority are low-molecular-weight organic compounds.

Common aldehydes, ketones, carboxylic acids, esters, alcohols, ethers, etc., among these compounds, there are aliphatic compounds, alicyclic compounds, aromatic compounds, and heterocyclic compounds. Aliphatic ring compounds: The molecule contains a carbon ring composed of more than 3 carbon atoms connected to the ring, and the two adjacent carbon atoms in the ring can be single, double or triple bonds, and the number of rings can be one or more compounds.

Such compounds include aliphatic cyclic hydrocarbons and their derivatives. Their properties are similar to those of their respective lipid chain compounds. Aromatic compounds:

A class of compounds that contain at least one benzene ring in a molecule and have unique properties (called aromaticity) that are different from open-chain compounds or aliphatic cyclic hydrocarbons. Aromatic hydrocarbons and aliphatic hydrocarbons can be regarded as two classifications of hydrocarbons, which are two complementary collections. Alicyclic hydrocarbons are a type of aliphatic hydrocarbons, which are the same cyclic hydrocarbons as aromatic hydrocarbons, but are similar in nature to aliphatic hydrocarbons.

Among aromatic compounds, aliphatic ring compounds, and aromatic compounds, the category of aromatized hand and limb compounds is significantly larger, and the aromatic compounds must contain at least one benzene ring, and the aliphatic ring compounds must contain non-benzene carbon rings. 2.Aliphatic hydrocarbons are named because they have the same basic properties as aliphatic compounds, i.e., lipids (including phospholipids, brain phospholipids, lecithins, sterols, glycolipids, lipoproteins), neutral fats, and fatty acids.

Classification of fatty acids: saturated fatty acids, unsaturated fatty acids (monounsaturated fatty acids, polyunsaturated fatty acids). Fatty alcohol classification:

Natural fatty alcohols, the other category is generally not stated.

Polycyclic aromatic hydrocarbons are a group of chemicals that are made from coal that has not been completely burned. Formed by oil and gas, garbage, or other organic substances. PAHs can be caused by natural processes or by physical actions associated with human activities.

There are more than 100 species. 10,000 different PAH compounds. The vast majority of PAHs do not exist alone in the environment, they tend to be mixtures of two or more PAHs.

They can also be found in some substances such as **, coal, hefin oil, and tar (bitumen) etc.

The name of aromatic compounds** was found in the early days of organic chemistry, and most of these compounds were found in volatile essential oils, fragrance resins, and other substances with fragrances. For example, benzoin acid (C7H6O2) is obtained from benzoin gum, benzaldehyde is obtained from bitter almond oil, toluene is derived from Tolu (a South American tree known as Tolutere Baisamum) balsam, and so on. Of course, this kind of classification based on smell is very unscientific.

Many of the compounds discovered later would be among the aromatic compounds by their nature, but they are not scented. As a result, the term aromatic compounds are still used, but they have lost their original meaning. What we now call aromatic compounds generally refers to compounds that contain benzene rings in their molecules.

What are the common characteristics of aromatic compounds?

From the point of view of experimental facts, aromatic compounds are a class of compounds whose molecular formula seems to be extremely unsaturated and difficult to undergo the addition reaction of unsaturated hydrocarbons.

From a theoretical point of view, there is a ring-forming delocalized electron cloud in the aromatic compound molecule above and below the ring. In addition, the electron cloud has a total of (4n+2) electrons. For example, when n=1, it is benzene, and it has 6 electrons If according to the Kekuler structure, the benzene molecule contains three double bonds, then its heat of hydration should be 3 times that of cyclohexene, but in fact, the heat of hydrogenation of benzene is only kj mol, which is smaller than expected kj mol.

This shows that 1 mol of C6H6 contains less actual energy than it should have in the Kekuler type, kj, so benzene is particularly stable. The energy difference of kj is due to the delocalization of electrons in the conjugated system of benzene ring. Therefore, this part of the energy is also called the conjugation energy or delocalization energy of benzene.

This is a value that should not be overlooked, because in the most common organic reactions, the activation energy is generally only 63 kJ mol and 105 kJ mol. In addition, the measured heat of combustion of benzene is lower than the calculated value, and it is about the same value.