Name of the indicator

Norm for toluene.

Test method

top variety OKP 24 1421 0110

first grade OKP 24 1421-0130

1. Appearance and color

A transparent liquid that does not contain extraneous impurities and water, not darker than the solution to 2 SG 2 O 7. Concentrations 0.003 g / dm 3

According to GOST 2706.1-74

2. Density at 20 ° C, g / cm 3

0,865-0,867

0,864-0,867

8. Water exhaust reaction

Neutral

According to GOST 2706.7-74

9. Evaporability

Evaporates without residue

According to GOST 2706.8-74

10. Mass fraction of common sulfur,%, no more

0,00015

Point number, subparagraph, enumeration, applications

Property of the working body (alcohol) in vacuum

The nomogram of the length of determination of the boiling point of substances under reduced pressure.

boiling temperature in vacuumfind with a nomogram (Fig. 76) at the continuation of a straight line connecting the boiling point of this substance at atmospheric pressure and the value of the residual pressure.

For approximate calculations, it is also possible to use an empirical rule: with a decrease in pressure, the boiling point of substances is reduced by about 15 ° C.

Diagram Pressure - Boiling Temperature Published by Maybridge Chemical Co., Ltd.

In order for the boiling point at a certain pressure to lead to 760 mm Hg. Art., Connect the straight line the corresponding values \u200b\u200bon the boards A and C. The desired size of the boiling point is read on the scale. V. If then combined the direct found value of the boiling point with any pressure value on the C, then the point of intersection of it with a scale and give approximate Boiling point corresponding to the selected pressure.

1 mm. RT. Art. \u003d 133.32 Pa \u003d 1,3158 · 10-3 atm

Source :: Gordon A., Ford R. Satellite Chemist: Physico-chemical properties, techniques, bibliography. - M.: Mir, 1976 - 510 p.

Boiling temperature, boiling point - The temperature at which the boil of a liquid under constant pressure occurs. The boiling point corresponds to the temperature of saturated steam above the flat surface of the boiling fluid, since the fluid itself is always a few overreal relative to the boiling point.

According to the Klapairone - Clausius equation with increasing pressure, the boiling point increases, and with a decrease in pressure, the boiling point is respectively decreased:

,
where - boiling point at atmospheric pressure, k,
- Specific heat evaporation, J / kg,
- molar mass, kg / mol,
- Universal gas constant.

The limiting boiling point is the critical temperature of the substance. So the boiling point of water will vary on the ground depending on the height: from 100 ° C at sea level up to 69 ° C on the vertex east. And with an even greater increase in the height, there will be a point in which it will be impossible to obtain liquid water: ice and steam will move directly into each other bypassing the liquid phase.

The boiling point of water depending on the pressure can be quite accurately calculated by the formula:

, ,

where the pressure is taken to MPa (ranging from 0.1 MPa to 22 MPa).

Constancy of boiling point

The boiling point at atmospheric pressure is usually given as one of the main physicochemical characteristics of the chemically pure matter.

However, data on the boiling temperature of super-free substances, in particular, such organic liquids such as ether and benzene can have significant differences from ordinary tabular data. This is due to the formation of associates, which can accumulate in fluid in the absence of water, as the mediator of establishing an equilibrium state. Thus, ultra-resistant benzene can be subjected to fractional distillation in the range of 90-118 ° C.

Parameters of critical points of some substances

Heat exchange

Physical properties of alcohol

Solvent density at different temperatures

The density values \u200b\u200b(g / cm 3) are given to the most common solvents at different temperatures.

Definition

Toluene (methylbenzene) - Chemical combination of organic nature, representative of the class of aromatic hydrocarbons, the nearest homolog of benzene. Toluene is a colorless liquid insoluble in water.

Gulf, burns with a smoking flame. It has a sharp smell, as well as a low-rise drug. The main physical constants of toluene are given in Table. 1. It is used in the production of explosives, benzoic acid, sugar, varnishes, typographical paints. It is used as an additive to motor fuel as a component of high-octane gasoline.

Table 1. Physical properties and toluene density.

Toluene is two orders of magnitude less toxic than benzene, due to the fact that it is oxidized in benzoic acid and excreted from the body. In all cases, where possible, benzene should be replaced by toluene.

Chemical composition and structure of toluene molecule

The chemical composition of toluene molecule can be reflected using an empirical formula C 6 H 5 -CH 3. The methyl radical is directly associated with the benzene ring 7, the structural formula of toluene looks like this:

Fig. 1. The structure of toluene molecule.

Brief description of chemical properties and toluene density

For toluene, as well as for all aromatic hydrocarbons, the reaction of substitution in the benzene ring, which proceed along the electroplated mechanism. Due to the presence in the composition of toluene of the radical methyl, the replacement of hydrogen atoms is most often occurring in an ortho or pair position:

Halogenation (toluene interacts with chlorine and bromine in the presence of catalysts - anhydrous ALCL 3, FECL 3, ALBR 3)

C 6 H 5 -CH 3 + CL 2 \u003d C 6 H 4 CL-CH 3 + HCl;

- Nuting (toluene easily reacts with a nitrifying mixture - a mixture of concentrated nitric and sulfuric acids)

- Alkylation on Fridet-Korfest

C 6 H 5 -CH 3 + CH 3 -CH (CH 3) -Cl \u003d CH 3 -C 6 H 4 -CH (CH 3) -CH 3 + HCl.

The reaction of the attachment to the toluene leads to the destruction of the aromatic system and proceed only in harsh environments:

- hydrogenation (reaction occurs when heated, catalyst - Pt)

C 6 H 5 -CH 3 + 3H 2 \u003d C 6 H 11 -CH 3.

As a result of oxidation of toluene, benzoic acid is formed:

5C 6 H 5 -CH 3 + 6KMNO 4 + 9H 2 SO 4 \u003d 5C 6 H 5 COOH + 6MNSO 4 + 3K 2 SO 4 + 14H 2 O;

The reaction of the interaction of toluene with chlorine in the light leads to a substitution in a hydrocarbon radical:

C 6 H 5 -CH 3 + CL 2 \u003d C 6 H 5 -CH 2 CL + HCl.

Examples of solving problems

Example 1.

Example 2.

Synonym - methylbenzene.. Colorless movable bat with a sharp smell. Mixed in unlimited limits with hydrocarbons, many alcohols and ether, while mixing toluene with water is impossible. Polymers dissolves: polystyrene at room temperature, polyethylene when heated. Gulf, burns with the highlight of the soot. Toluol was first allocated from Toluansky Balzam - a yellowish-brown, pleasantly smelling resin of the South American Toluifera Balsamum tree. Hence the name - Toluene. This balm was used to prepare money from cough and in perfumery. Currently, toluene is obtained from oil fractions and coal tar or in the processes of catalytic reforming of gasoline fractions and pyrolysis. It is allocated with selective extraction and subsequent rectification.
The coal toluene, which formed during the coking process, is extracted from coke gas as a component of raw benzene, is subjected to sulfuric acid (to remove unsaturated and sulfur-containing compounds) and distinguished by rectification.
A significant amount of toluene is obtained as a by-product in the synthesis of styrene from benzene and ethylene.
Couples easily form explosive mixtures, flammable even from the spark of static electricity.

Toloole application:

Toluol is a valuable raw material for organic synthesis, for the production of components of motor fuels with a high octane number, to obtain explosives (trinitrotoluola), pharmaceutical preparations, dyes and solvents. As the main component is included in the mixture solvents (, p-4a, p-5a, p-12) used to dissolve in the manufacture and applying epoxy, vinyl, acrylic, nitrocellulose, chlorinated paints and varnish materials. Practical significance has oxidation reactions, as a result of such a reaction, benzoic acid is obtained. To obtain benzoic acid, the oxidation of toluene by air or air oxygen is used. The process is carried out or in steam, or in the liquid phase. Liquid phase processes in industry are used by the bowl.

Danger for man:

Toluene is a toxic product (a class of danger - third). Toloole pairs at high concentrations have a narcotic effect on a person, causing strong hallucinations and dissociative state. Until 1998, Toluol was part of the popular "moment" glue, which became popular with toxicomicians. Increased triggers of toluene vapor also have a harmful effect on the human nervous system, irritate effect on the skin, as well as the mucous membranes of the eyes. Being a strong toxic poison, it affects the function of the body's blood formation. The result of blood breeding is diseases such as cyanosis, hypoxia. There are toluene toxicism, simultaneously having a carcinogenic effect. The pairs penetrate through the respiratory organs or intact skin, cause damage to the nervous system (there is an injury and disorders of the vestibular apparatus. Sometimes these processes are irreversible.
In the air of the working area, the regulatory documents regulates the maximum permissible content of the vapor:
- the maximum one-time concentration - 150 mg / m3;
- Medium-average concentration - 50 mg / m3.
Working with toluene and solvents based on it is necessary in resistant to their effects of rubber gloves, be sure to be used in a well-ventilated room.

Fire Danger:

Highly flammable. Toluene belongs to a class of 3.1 LVZ with a flash point of less than +23 degrees. Do not allow open fire, sparks and smoking. A mixture of toluene vapor with air is explosive.
With drain-liquid operations, it is necessary to strictly follow the rules for protection against static electricity in the industries of the chemical, petrochemical and oil refineries. Production premises in which work is underway with toluene must be provided with air-exhaust ventilation, and local suction equipment. In the premises for storage and use of toluene, open fire is prohibited, as well as the use of tools that give a spark. Electrical equipment and artificial lighting should be performed in explosion-proof performance. To extinguish toluene, it is necessary to use fine water, chemical and air-mechanical foam. To extinguish small foci of burning, manual foam or carbon dioxide fire extinguishers are used. When breaking toluene, the neutralization of snowing sand with a removal of it in a specially designated place.