What are Organic Compounds?

Organic compounds in the narrow sense are mainly composed of carbon and hydrogen. They must be carbon-containing compounds, but do not include carbon oxides and sulfides, carbonic acid, carbonates, cyanides, thiocyanates, and cyanates. , Carbides, carboranes, metal carbonyls, metal-organic ligand complexes without MC bonds, some metal-organic compounds (substances containing MC bonds), and other carbon-containing substances that have been mainly studied in inorganic chemistry . ^[1-3]

"Organic matter" was originally intended to be a substance derived from living organisms, as organic matter discovered earlier were separated from the body. With the development of organic synthesis, many organic substances can be synthesized from inorganic substances in the laboratory. The word "organic matter" has lost its original meaning. ^[4]

Except for carbon, most organic compounds contain

Earlier, it was known

There are many types of organic matter, which can be divided into hydrocarbons and hydrocarbons.

Organic compounds: a great variety and number (more than 30 million are known and growing at a rate of millions each year). But there are few constituent elements, such as C, H, O, N, P, S, X (halogen: F, Cl, Br, I) and so on.

1. Bonding characteristics of carbon atoms in organic compounds

The outermost layer of the carbon atom has 4 electrons, and it is not easy to lose or gain electrons to form cations or anions. Carbon atoms form covalent compounds with various non-metals such as hydrogen, oxygen, nitrogen, sulfur, and phosphorus through covalent bonds.

Due to the characteristics of carbon atom bonding, each carbon atom can not only form 4 covalent bonds with hydrogen atoms or other atoms, but also the carbon atoms can be combined by covalent bonds. Carbon atoms can form not only stable single bonds, but also stable double or triple bonds. Multiple carbon atoms can be combined with each other to grow different short carbon chains. The carbon chains can also have branched chains and can also be combined into carbon rings. The carbon chain and the carbon ring can also be combined with each other. Therefore, for molecules with the same type of atoms and the same number of each type of atoms, there may be multiple different ways of combining the atoms to form molecules with different structures.

2. Isomerism of organic compounds

Compounds have the same molecular formula, but different structures, so there are differences in properties. This phenomenon is called isomerism. Compounds with isomerism are isomers of each other. In organic compounds, as the number of carbon atoms increases, the number of isomers increases. The isomer phenomenon is very common in organic materials, which is one of the reasons why the number of organic compounds in nature is very large.

(1) Most of them are flammable

(2) Most of the stability is poor (organic compounds often decompose due to the influence of temperature, bacteria, air or light)

In organic chemistry, in order to have a reasonable and convenient way to express the stereochemical relationship of asymmetric compounds, RS Ingod, RC Kane, and V. Prelug et al. Proposed to arrange the substituent groups by atomic number. The highest atomic number is placed first, and the lowest is placed last. Its method is called the priority rule of the atom or atomic group, or the order rule or order rule. When deciding on the priority of an atom or a group, certain rules are formulated, and the main contents are as follows:

The various substituent atoms are arranged according to their atomic number. The larger one is the "better" group. If it is an isotope, the higher quality is the "better" group. For example Cl> O> C> H; D> H, ">" means better.

If the first element of two groups is the same (such as C), then compare several atoms directly connected to it. The comparison is arranged according to the atomic number. First, the largest one in each group is compared. If it is still the same, then the second and third are compared. For example, Cl, H, H> O, O, C; Cl, O, H> Cl, C, C. If they are still the same, they are compared successively along the substitution chain.

Groups containing double and triple bonds are treated as two or three single bonds, and it can be considered that two or three identical atoms are connected.

Having mastered the order of substituents, not only can the Z. E designation in geometric isomerization be correctly represented, but also the configuration RS of optical isomers can be correctly judged. When naming a compound, the atoms or groups of substituents in the same compound should be arranged in a regular order, with the preferred group being the last. ^[8]

In the process of pharmaceutical production, research, and inspection, problems such as separation, purification, and identification of organic compounds are often encountered. The identification, separation and purification of organic compounds are three related but different concepts.

The purpose of separation and purification is to obtain pure materials from the mixture, but the requirements are different and the processing methods are different. Separation is the separation of each component of the mixture. In the separation process, a certain component in the mixture is often converted into a new compound through a chemical reaction, and after separation, it is reduced to the original compound. There are three cases of purification. One is to convert the impurities into the desired compound. The second is to convert the impurity into another compound through an appropriate chemical reaction to separate it (the separated compound does not need to be reduced again). It is separated by physical methods (liquid separation, chromatography, etc.).

Identification is based on the different properties of a compound to determine what functional group it contains and which compound it is. If identifying a group of compounds, it is sufficient to determine which one is each.

Organic compounds are qualified

When doing identification questions, please note that not all chemical properties of compounds can be used for identification. Certain conditions must be met:

(1) there is a color change in the chemical reaction;

(2) accompanied by obvious temperature changes (exothermic or endothermic) during the chemical reaction;

(3) Gas is generated from reaction products;

(4) The reaction products include the formation of precipitates or the dissolution of the precipitates during the reaction, and the product layering.

Specific methods for organic compounds

1, unsaturated bonds:

(1) Carbon tetrachloride solution of bromine, red color faded. False positive: Bromine is extracted.

(2) The solution of potassium permanganate fades purple.

2. Alkyne containing alkyne:

(1) Silver nitrate to form silver acetylide white precipitate.

(2) Ammonia solution of cuprous chloride to produce a red precipitate of cuprous alkyne.

3. Small cyclic hydrocarbons: Four-membered alicyclic hydrocarbons can make bromine carbon tetrachloride solution leg color.

4. Halogenated hydrocarbons: Alcoholic solution of silver nitrate generates silver halide precipitation; different structures of halogenated hydrocarbons generate different precipitation speeds, tertiary halogenated hydrocarbons and allylic halogenated hydrocarbons are fastest, secondary halogenated hydrocarbons are next, Primary halogenated hydrocarbons need to be heated before precipitation occurs. You can determine which halogen is based on the color of the precipitate.

5. Alcohol:

(1) Reacts with metallic sodium to emit hydrogen (identify alcohols with less than 6 carbon atoms).

(2) The primary, secondary, and tertiary alcohols were identified using Lucas reagent. The tertiary alcohol immediately became turbid. The secondary alcohol became turbid after being placed, and the primary alcohol remained unchanged after being placed.

(3) O-diol reacts with copper ions to produce osmium blue precipitate.

6. Phenol or enol compounds:

(1) Use ferric chloride solution to produce color (phenol produces blue-violet).

(2) Phenol and bromine water produce tribromophenol as a white precipitate.

7. Carbonyl compounds:

(1) Identification of all aldehydes and ketones: 2,4-dinitrophenylhydrazine, resulting in yellow or orange-red precipitation. Grignard reagents can also be used.

(2) To distinguish aldehydes from ketones, dolen reagents can form silver mirrors, while ketones cannot.

(3) Distinguish aromatic aldehydes from fatty aldehydes or ketones from fatty aldehydes. With Fehling's reagent, fatty aldehydes produce brick red precipitates, while ketones and aromatic aldehydes cannot.

(4) Identify methyl ketones and alcohols with a structure, and use sodium hydroxide solution of iodine to form a yellow iodoform precipitate.

8. Formic acid:

With silver ammonia solution, formic acid can form silver mirror, while other acids cannot.

9. Amine : There are two ways to distinguish primary, secondary and tertiary amines:

(1) Use benzenesulfonyl chloride or p-toluenesulfonyl chloride to react in NaOH solution. The product produced by the primary amine is soluble in NaOH; the product produced by the secondary amine is not soluble in the NaOH solution; the tertiary amine does not react.

(2) With NaNO ₂ + HCl:

Fatty amines: Primary amines emit nitrogen, secondary amines form a yellow oil, and tertiary amines do not react.

Aromatic amines: primary amines form diazonium salts, secondary amines form yellow oils, and tertiary amines form orange (acidic conditions) or green solids (basic conditions).

10 sugar:

(1) Monosaccharides can interact with Torun reagent and Fehling reagent to produce silver mirror or brick red precipitate.

(2) Glucose and fructose: Bromine water can be used to distinguish glucose from fructose. Glucose can discolor bromine water, but fructose cannot.

(3) Maltose and sucrose: With Torun reagent or Fehling reagent, maltose can produce silver mirror or brick red precipitate, while sucrose cannot. ^[9]