Along with hydrocarbons C but H in, which include atoms of two types - C and H, oxygen-containing organic compounds of type C are known but H in ABOUT from. In topic 2, we will look at oxygen-containing compounds that differ in:
1) the number of O atoms in the molecule (one, two or more);
2) the multiplicity of the carbon–oxygen bond (single C–O or double C=O);
3) the type of atoms connected to oxygen (C–O–H and C–O–C).

Lesson 16
Monohydric saturated alcohols

Alcohols are derivatives of hydrocarbons. general formula ROH, where R is a hydrocarbon radical. The formula of alcohol is obtained from the formula of the corresponding alkane by replacing the H atom with the OH group: RN RON.
You can derive the chemical formula of alcohols in another way, including the oxygen atom O between the atoms
С–Н hydrocarbon molecules:

RN RON, CH 3 -H CH 3 -O-H.

The hydroxyl group OH is functional group of alcohols. That is, the OH group is a feature of alcohols; it determines the main physical and chemical properties of these compounds.

The general formula of monohydric saturated alcohols is C n H2 n+1OH.

Names of alcohols obtained from the names of hydrocarbons with the same number of C atoms as in alcohol, by adding the suffix - ol-. For example:

The name of alcohols as derivatives of the corresponding alkanes is typical for compounds with a linear chain. The position of the OH group in them is at the extreme or at the internal atom
C - indicate the number after the name:

The names of alcohols - derivatives of branched hydrocarbons - are made in the usual way. The main carbon chain is chosen, which should include a C atom connected to an OH group. The C atoms of the main chain are numbered so that the carbon with the OH group gets a lower number:

The name is composed, starting with the number indicating the position of the substituent in the main carbon chain: “3-methyl ...” Then the main chain is called: “3-methylbutane ...” Finally, the suffix is ​​\u200b\u200badded - ol-(name of the OH group) and the number indicates the carbon atom to which the OH group is bound: "3-methylbutanol-2".
If there are several substituents on the main chain, they are listed sequentially, indicating the position of each with a number. Repeating substituents in the name are written using the prefixes "di-", "tri-", "tetra-", etc. For example:

Isomerism of alcohols. Isomers of alcohols have the same molecular formula, but a different order of connection of atoms in molecules.
Two types of alcohol isomerism:
1) isomerism of the carbon skeleton;
2)isomerism of the position of the hydroxyl group in the molecule.
Let's imagine the isomers of alcohol C 5 H 11 OH of these two types in a linear-angular notation:

According to the number of C atoms associated with the alcohol (–C–OH) carbon, i.e. adjacent to it, alcohols are called primary(one neighbor C), secondary(two C) and tertiary(three C-substituents at carbon –C–OH). For example:

A task. Make up one isomer of alcohols of the molecular formula C 6 H 13 OH with main carbon chain:

a) C 6, b) From 5 , in) From 4 , G) From 3

and name them.

Solution

1) We write down the main carbon chains with a given number of C atoms, leaving room for H atoms (we will indicate them later):

a) C-C-C-C-C-C; b) C–C–C–C–C; c) C–C–C–C; d) C-C-C.

2) Arbitrarily choose the place of attachment of the OH group to the main chain and indicate the carbon substituents at the internal C atoms:

In example d) it is not possible to place three substituents CH 3 - at the C-2 atom of the main chain. Alcohol C 6 H 13 OH has no isomers with a three-carbon main chain.

3) We arrange the H atoms at the carbons of the main chain of isomers a) - c), guided by the valency of carbon C (IV), and name the compounds:

EXERCISES.

1. Underline the chemical formulas of saturated monohydric alcohols:

CH 3 OH, C 2 H 5 OH, CH 2 \u003d CHCH 2 OH, CHCH 2 OH, C 3 H 7 OH,

CH 3 CHO, C 6 H 5 CH 2 OH, C 4 H 9 OH, C 2 H 5 OS 2 H 5, NOCH 2 CH 2 OH.

2. Name the following alcohols:

3. Make structural formulas according to the names of alcohols: a) hexanol-3;
b) 2-methylpentanol-2; c) n-octanol; d) 1-phenylpropanol-1; e) 1-cyclohexylethanol.

4. Compose the structural formulas of the isomers of alcohols of the general formula C 6 H 13 OH :
a) primary; b) secondary; c) tertiary.Name these alcohols.

5. According to the linear-angular (graphical) formulas of compounds, write down their structural formulas and give names to the substances:

Lesson 17

Low molecular weight alcohols - methanol CH 3 OH, ethanol C 2 H 5 OH, propanol C 3 H 7 OH, and isopropanol (CH 3) 2 CHOH - colorless mobile liquids with a specific alcoholic odor. High boiling points: 64.7 ° C - CH 3 OH, 78 ° C - C 2 H 5 OH, 97 ° C - n-C 3 H 7 OH and 82 ° C - (CH 3) 2 CHOH - are due to intermolecular hydrogen bond existing in alcohols. Alcohols C (1) -C (3) are miscible with water (dissolve) in any ratio. These alcohols, especially methanol and ethanol, are the most widely used in industry.

1. methanol synthesized from water gas:

2. ethanol receive ethylene hydration(by adding water to C 2 H 4):

3. Another way to get ethanol – fermentation of sugary substances by the action of yeast enzymes. The process of alcoholic fermentation of glucose (grape sugar) has the form:

4. ethanol receive from starch, as well as wood(cellulose) by hydrolysis to glucose and subsequent fermentation to alcohol:

5. Higher alcohols receive from halogenated hydrocarbons by hydrolysis Under the influence aqueous solutions alkalis:

A task.How to get propanol-1 from propane?

Solution

Of the five methods proposed above for the production of alcohols, none of them considers the production of alcohol from an alkane (propane, etc.). Therefore, the synthesis of propanol-1 from propane will include several stages. According to method 2, alcohols are obtained from alkenes, which in turn are available by dehydrogenation of alkanes. The process flow is as follows:

Another scheme for the same synthesis is one step longer, but it is easier to implement in the laboratory:

The addition of water to propene at the last stage proceeds according to Markovnikov's rule and leads to secondary alcohol - propanol-2. The task requires obtaining propanol-1. Therefore, the problem is not solved, we are looking for another way.
Method 5 consists in the hydrolysis of haloalkanes. The necessary intermediate for the synthesis of propanol-1 - 1-chloropropane - is obtained as follows. Chlorination of propane gives a mixture of 1- and 2-monochloropropanes:

1-chloropropane is isolated from this mixture (for example, using gas chromatography or due to different boiling points: for 1-chloropropane t bp = 47 °C, for 2-chloropropane t bp = 36 °C). The target propanol-1 is synthesized by the action of KOH or NaOH on 1-chloropropane with aqueous alkali:

Please note that the interaction of the same substances: CH 3 CH 2 CH 2 Cl and KOH - depending on the solvent (alcohol C 2 H 5 OH or water) leads to different products - propylene
(in alcohol) or propanol-1 (in water).

EXERCISES.

1. Give the reaction equations for the industrial synthesis of methanol from water gas and ethanol by ethylene hydration.

2. Primary alcohols RCH 2 OH obtained by hydrolysis of primary alkyl halides RCH 2 Hal, and secondary alcohols are synthesized by hydration of alkenes. Complete the reaction equations:

3. Suggest methods for obtaining alcohols: a) butanol-1; b) butanol-2;
c) pentanol-3, based on alkenes and alkyl halides.

4. During the enzymatic fermentation of sugars, along with ethanol, a mixture of primary alcohols is formed in a small amount. C 3 -C 5 - fusel oil. The main component in this mixture is isopentanol.(CH 3) 2 CHCH 2 CH 2 OH, minor components – n-C 3 H 7 OH, (CH 3) 2 CHCH 2 OH and CH 3 CH 2 CH (CH 3) CH 2 OH. Name these "fusel" spirits according to the IUPAC nomenclature. Write an equation for the reaction of glucose fermentation C 6 H 12 O 6, in which all four impurity alcohols would be obtained in a molar ratio of 2:1:1:1, respectively. Enter the gas CO 2 to the right side of the equation in the amount of 1/3 mol of all initial atoms FROM , as well as the required number of molecules H 2 O.

5. Give the formulas of all aromatic alcohols of the composition C 8 H 10 O. (In aromatic alcohols, the group IS HE removed from benzene ring one or more atoms FROM:
C 6 H 5 – (CH 2)n – IS HE.)

Answers to exercises for topic 2

Lesson 16

1. The chemical formulas of saturated monohydric alcohols are underlined:

CH 3 IS HE, FROM 2 H 5 IS HE, CH 2 \u003d CHCH 2 OH, CH CH 2 OH, FROM 3 H 7 IS HE,

CH 3 CHO, C 6 H 5 CH 2 OH, FROM 4 H 9 IS HE, C 2 H 5 OS 2 H 5, NOCH 2 CH 2 OH.

2. Names of alcohols according to structural formulas:

3. Structural formulas by the names of alcohols:

4. Isomers and names of alcohols of the general formula C 6 H 13 OH:

5. Structural formulas and names compiled according to graphical connection diagrams:

(alcohols) – class organic compounds containing one or more C-OH groups, while the OH hydroxyl group is bonded to an aliphatic carbon atom (compounds in which the carbon atom in the C-OH group is part of the aromatic nucleus are called phenols)

The classification of alcohols is diverse and depends on which feature of the structure is taken as the basis.

1. Depending on the number of hydroxyl groups in the molecule, alcohols are divided into:

a) monoatomic (contain one hydroxyl OH group), for example, methanol CH 3 OH, ethanol C 2 H 5 OH, propanol C 3 H 7 OH

b) polyatomic (two or more hydroxyl groups), for example, ethylene glycol

HO -С H 2 - CH 2 - OH , glycerol HO-CH 2 -CH (OH) -CH 2 -OH, pentaerythritol C (CH 2 OH) 4.

Compounds in which one carbon atom

there are two hydroxyl groups, in most cases they are unstable and easily turn into aldehydes, while splitting off water: RCH (OH) 2 ® RCH \u003d O + H 2 O , does not exist.

2. According to the type of carbon atom to which the OH group is bonded, alcohols are divided into:

a) primary, in which the OH group is bonded to the primary carbon atom. The primary carbon atom is called (highlighted in red), associated with only one carbon atom. Examples of primary alcohols - ethanol C

H 3 - CH 2 - OH, propanol C H 3 - CH 2 - CH 2 - OH. b) secondary, in which the OH group is bonded to a secondary carbon atom. The secondary carbon atom (highlighted in blue) is bonded simultaneously to two carbon atoms, for example, secondary propanol, secondary butanol (Fig. 1).

Rice. one. STRUCTURE OF SECONDARY ALCOHOLS

c) tertiary, in which the OH group is bonded to the tertiary carbon atom. The tertiary carbon atom (highlighted in green) is bonded simultaneously to three neighboring carbon atoms, for example, tertiary butanol and pentanol (Fig. 2).

Rice. 2. STRUCTURE OF TERTIARY ALCOHOLS

The alcohol group attached to it is also called primary, secondary, or tertiary, according to the type of carbon atom.

In polyhydric alcohols containing two or more OH groups, both primary and secondary HO groups can be present simultaneously, for example, in glycerol or xylitol (Fig. 3).

Rice. 3. COMBINATION OF PRIMARY AND SECONDARY OH-GROUPS IN THE STRUCTURE OF POLYATOMIC ALCOHOLS.

3. According to the structure of organic groups linked by an OH group, alcohols are divided into saturated (methanol, ethanol, propanol), unsaturated, for example, allyl alcohol CH 2 \u003d CH - CH 2 -OH, aromatic (for example, benzyl alcohol C 6 H 5 CH 2 OH), containing in the group

R aromatic group.

Unsaturated alcohols, in which the OH group "adjoins" the double bond, i.e. bound to a carbon atom that simultaneously participates in the formation of a double bond (for example, vinyl alcohol CH 2 \u003d CH–OH), are extremely unstable and isomerize immediately ( cm.ISOMERIZATION) to aldehydes or ketones:

CH 2 \u003d CH–OH ® CH 3 -CH \u003d O Nomenclature of alcohols. For common alcohols with a simple structure, a simplified nomenclature is used: the name of the organic group is converted into an adjective (using the suffix and the ending " new”) and add the word “alcohol”:In the case when the structure of the organic group is more complex, the rules common to all organic chemistry are used. Names compiled according to such rules are called systematic. In accordance with these rules, the hydrocarbon chain is numbered from the end to which the OH group is closest. Next, this numbering is used to indicate the position of various substituents along the main chain, the suffix “ol” and a number indicating the position of the OH group are added to the end of the name (Fig. 4):4. SYSTEMATIC NAMES OF ALCOHOLS. Functional (OH) and substituent (CH 3) groups, as well as their corresponding digital indices, are highlighted in different colors.The systematic names of the simplest alcohols are made according to the same rules: methanol, ethanol, butanol. For some alcohols, trivial (simplified) names that have developed historically have been preserved: propargyl alcohol NSє C-CH 2 -OH, glycerol HO-CH 2 -CH (OH) -CH 2 -OH, pentaerythritol C (CH 2 OH) 4, phenethyl alcohol C 6 H 5 -CH 2 -CH 2 -OH.Physical properties of alcohols. Alcohols are soluble in most organic solvents, the first three simplest representatives - methanol, ethanol and propanol, as well as tertiary butanol (H 3 C) 3 COH - are miscible with water in any ratio. With an increase in the number of C atoms in organic group the hydrophobic (water-repellent) effect begins to affect, solubility in water becomes limited, and when R containing more than 9 carbon atoms, practically disappears.

Due to the presence of OH groups, hydrogen bonds form between alcohol molecules.

Rice. five. HYDROGEN BONDS IN ALCOHOLS(shown by dotted line)

As a result, all alcohols have a higher boiling point than the corresponding hydrocarbons, for example, T. kip. ethanol + 78 ° C, and T. kip. ethane –88.63°C; T. kip. butanol and butane +117.4°C and –0.5°C, respectively.

Chemical properties of alcohols. Alcohols are distinguished by various transformations. The reactions of alcohols have some general patterns: the reactivity of primary monohydric alcohols is higher than secondary ones, in turn, secondary alcohols are chemically more active than tertiary ones. For dihydric alcohols, in the case when OH groups are located at neighboring carbon atoms, an increased (in comparison with monohydric alcohols) reactivity is observed due to the mutual influence of these groups. For alcohols, reactions are possible that take place with the cleavage of both C–O and O–H bonds.

1. Reactions proceeding through the О–Н bond.

When interacting with active metals (Na, K, Mg, Al), alcohols exhibit the properties of weak acids and form salts called alcoholates or alkoxides:

CH 3 OH + 2 Na ® 2 CH 3 OK + H 2

Alcoholates are chemically unstable and hydrolyze under the action of water to form alcohol and metal hydroxide:

C 2 H 5 OK + H 2 O

® C 2 H 5 OH + KOH

This reaction shows that alcohols are weaker acids compared to water (a strong acid displaces a weak one), in addition, when interacting with alkali solutions, alcohols do not form alcoholates. However, in polyhydric alcohols (in the case when OH groups are attached to neighboring C atoms), the acidity of alcohol groups is much higher, and they can form alcoholates not only when interacting with metals, but also with alkalis:

HO–CH 2 –CH 2 –OH + 2NaOH ® NaO–CH 2 –CH 2 –ONa + 2H 2 OWhen the HO groups in polyhydric alcohols are attached to non-adjacent C atoms, the properties of alcohols are close to monohydric, since the mutual influence of HO groups does not appear.

When interacting with mineral or organic acids, alcohols form esters - compounds containing a fragment

R-O-A (A is the rest of the acid). Education esters also occurs when alcohols react with anhydrides and acid chlorides carboxylic acids (Fig. 6).

Under the action of oxidizing agents (K 2 Cr 2 O 7, KMnO 4), primary alcohols form aldehydes, and secondary alcohols form ketones (Fig. 7)

Rice. 7. FORMATION OF ALDEHYDES AND KETONES DURING THE OXIDATION OF ALCOHOLS

The reduction of alcohols leads to the formation of hydrocarbons containing the same number of C atoms as the initial alcohol molecule (Fig. 8).

8. RECOVERY OF BUTANOL

2. Reactions taking place at the C–O bond.

In the presence of catalysts or strong mineral acids, alcohols are dehydrated (water is split off), while the reaction can go in two directions:

a) intermolecular dehydration with the participation of two molecules of alcohol, while the C–O bonds in one of the molecules break, resulting in the formation of ethers - compounds containing a fragment

R-O-R (Fig. 9A).

b) during intramolecular dehydration, alkenes are formed - hydrocarbons with a double bond. Often, both processes—the formation of an ether and an alkene—occur in parallel (Fig. 9B).

In the case of secondary alcohols, during the formation of an alkene, two directions of the reaction are possible (Fig. 9C), the predominant direction is that in which hydrogen is split off from the least hydrogenated carbon atom during condensation (marked with the number 3), i.e. surrounded by fewer hydrogen atoms (compared to atom 1). Shown in fig. 10 reactions are used to produce alkenes and ethers.

The breaking of the C–O bond in alcohols also occurs when the OH group is replaced by a halogen, or an amino group (Fig. 10).

Rice. 10. REPLACEMENT OF OH-GROUP IN ALCOHOLS WITH HALOGEN OR AMINE GROUP

The reactions shown in fig. 10 are used to produce halocarbons and amines.

Getting alcohols. Some of the reactions shown above (Fig. 6,9,10) are reversible and, under changing conditions, can proceed in the opposite direction, leading to the production of alcohols, for example, during the hydrolysis of esters and halocarbons (Fig. 11A and B, respectively), as well as hydration alkenes - by adding water (Fig. 11B).

Rice. eleven. PRODUCTION OF ALCOHOLS BY HYDROLYSIS AND HYDRATION OF ORGANIC COMPOUNDS

The hydrolysis reaction of alkenes (Fig. 11, scheme B) underlies the industrial production of lower alcohols containing up to 4 carbon atoms.

Ethanol is also formed during the so-called alcoholic fermentation of sugars, for example, glucose C 6 H 12 O 6. The process proceeds in the presence of yeast fungi and leads to the formation of ethanol and CO 2:

® 2C 2 H 5 OH + 2CO 2

Fermentation can produce no more than a 15% aqueous solution of alcohol, since yeasts die at a higher concentration of alcohol. Alcohol solutions of higher concentration are obtained by distillation.

Methanol is obtained in industry by the reduction of carbon monoxide at 400

° C under a pressure of 20–30 MPa in the presence of a catalyst consisting of oxides of copper, chromium, and aluminum:® H 3 SON If instead of hydrolysis of alkenes (Fig. 11) oxidation is carried out, then dihydric alcohols are formed (Fig. 12) 12. OBTAINING DIATOMIC ALCOHOLSThe use of alcohols. The ability of alcohols to participate in various chemical reactions allows them to be used to obtain all kinds of organic compounds: aldehydes, ketones, carboxylic acids, ethers and esters used as organic solvents in the production of polymers, dyes and drugs.

Methanol CH 3 OH is used as a solvent, as well as in the production of formaldehyde, used to obtain phenol-formaldehyde resins, in Lately methanol is considered as a promising motor fuel. Large volumes of methanol are used in the production and transportation of natural gas. Methanol is the most toxic compound among all alcohols, the lethal dose when taken orally is 100 ml.

Ethanol C 2 H 5 OH is the starting compound for the production of acetaldehyde, acetic acid, and also for the production of esters of carboxylic acids used as solvents. In addition, ethanol is the main component of all alcoholic beverages, it is also widely used in medicine as a disinfectant.

Butanol is used as a solvent for fats and resins, in addition, it serves as a raw material for the production of aromatic substances (butyl acetate, butyl salicylate, etc.). In shampoos, it is used as a component that increases the transparency of solutions.

Benzyl alcohol C 6 H 5 -CH 2 -OH in the free state (and in the form of esters) is found in the essential oils of jasmine and hyacinth. It has antiseptic (disinfecting) properties, in cosmetics it is used as a preservative for creams, lotions, dental elixirs, and in perfumery as a fragrant substance.

Phenethyl alcohol C 6 H 5 -CH 2 -CH 2 -OH has the smell of a rose, is found in rose oil, and is used in perfumery.

Ethylene glycol HOCH 2 -CH 2 OH is used in the production of plastics and as an antifreeze (an additive that reduces the freezing point of aqueous solutions), in addition, in the manufacture of textile and printing inks.

Diethylene glycol HOCH 2 -CH 2 OCH 2 -CH 2 OH is used to fill hydraulic brake devices, as well as in textile industry when finishing and dyeing fabrics.

Glycerol

HOCH 2 - CH (OH) - CH 2 OH used to obtain polyester glyptal resins, in addition, it is a component of many cosmetic preparations. Nitroglycerin (Fig. 6) is the main component of dynamite used in mining and railway construction as an explosive.

Pentaerythritol (

HOCH 2) 4 C is used to produce polyesters (pentaphthalic resins), as a hardener for synthetic resins, as a plasticizer for polyvinyl chloride, and also in the production of tetranitropentaerythritol explosive.

Polyhydric alcohols xylitol HOCH 2 - (CHOH) 3 -CH 2 OH and sorbitol neNOCH 2 - (CHOH) 4 -CH 2 OH have a sweet taste, they are used instead of sugar in the production of confectionery for diabetics and obese people. Sorbitol is found in rowan and cherry berries.

Mikhail Levitsky

LITERATURE Shabarov Yu.S. Organic chemistry . Moscow, "Chemistry", 1994

Alcohols are derivatives of hydrocarbons containing one or more -OH groups, called a hydroxyl group or hydroxyl.

Alcohols are classified:

1. According to the number of hydroxyl groups contained in the molecule, alcohols are divided into monoatomic (with one hydroxyl), diatomic (with two hydroxyls), triatomic (with three hydroxyls) and polyhydric.

Like saturated hydrocarbons, monohydric alcohols form a regularly constructed series of homologues:

As in others homologous series, each member of the series of alcohols differs in composition from the previous and subsequent members by the homological difference (-CH 2 -).

2. Depending on the carbon atom at which the hydroxyl is located, primary, secondary and tertiary alcohols are distinguished. The molecules of primary alcohols contain a -CH 2 OH group associated with one radical or with a hydrogen atom at methanol (hydroxyl at the primary carbon atom). Secondary alcohols are characterized by a >CHOH group associated with two radicals (hydroxyl at the secondary carbon atom). The molecules of tertiary alcohols have a >C-OH group associated with three radicals (hydroxyl at the tertiary carbon atom). Denoting the radical by R, we can write the formulas of these alcohols in general form:

In accordance with the IUPAC nomenclature, when constructing the name of a monohydric alcohol, the suffix -ol is added to the name of the parent hydrocarbon. If there are higher functions in the compound, the hydroxyl group is denoted by the prefix hydroxy- (in Russian, the prefix oxy- is often used). As the main chain, the longest unbranched chain of carbon atoms is selected, which includes a carbon atom associated with a hydroxyl group; if the compound is unsaturated, then the multiple bond is also included in this chain. It should be noted that when determining the beginning of the numbering, the hydroxyl function usually takes precedence over halogen, double bond and alkyl, therefore, the numbering starts from the end of the chain, closer to which the hydroxyl group is located:

The simplest alcohols are named according to the radicals to which the hydroxyl group is connected: (CH 3) 2 CHOH - isopropyl alcohol, (CH 3) 3 COH - tert-butyl alcohol.

The rational nomenclature of alcohols is often used. According to this nomenclature, alcohols are considered as derivatives of methyl alcohol - carbinol:

This system is convenient in cases where the name of the radical is simple and easy to construct.

2. Physical properties of alcohols

Alcohols have higher boiling points and are significantly less volatile, have higher melting points, and are more soluble in water than the corresponding hydrocarbons; however, the difference decreases with increasing molecular weight.

The difference in physical properties is due to the high polarity of the hydroxyl group, which leads to the association of alcohol molecules through hydrogen bonding:

Thus, the higher boiling points of alcohols compared to the boiling points of the corresponding hydrocarbons are due to the need to break hydrogen bonds during the transition of molecules to the gas phase, which requires additional energy. On the other hand, this type of association leads, as it were, to an increase in molecular weight, which naturally leads to a decrease in volatility.

Alcohols with low molecular weight highly soluble in water, this is understandable, given the possibility of the formation of hydrogen bonds with water molecules (water itself is associated to a very large extent). In methyl alcohol, the hydroxyl group makes up almost half the mass of the molecule; no wonder, therefore, that methanol is miscible with water in all respects. As the size of the hydrocarbon chain in alcohol increases, the effect of the hydroxyl group on the properties of alcohols decreases, respectively, the solubility of substances in water decreases and their solubility in hydrocarbons increases. The physical properties of high molecular weight monohydric alcohols are already very similar to those of the corresponding hydrocarbons.

Alcohols- these are derivatives of hydrocarbons, the molecules of which contain one or more hydroxyl OH - groups associated with a saturated carbon atom.

Nomenclature: systematic - the ending - ol is added to the name of the corresponding hydrocarbon, the position of the OH group is indicated by a number; use trivial names.

CLASSIFICATION

By the number of OH - groups alcohols are divided into

● monoatomic

● diatomic (diols)

● triatomic (triols)

● polyhydric (polyols)

Depending on the position of OH groups distinguish

● primary

● secondary

● tertiary

Depending on the nature of the radical R distinguish

● rich

● unsaturated

● aromatic

● alicyclic

isomerism

1. Carbon skeleton

2. The position of the functional group:

3. Interclass isomerism (alcohols are isomeric to the class of ethers)

§3. Methods for obtaining monohydric alcohols.

1. Hydration of alkenes

Depending on the building unsaturated hydrocarbon primary, secondary and tertiary alcohols can be formed:

ethylene ethanol

propylene 2-propanol

methylpropene 2-methyl-2-propanol

2. Hydrolysis of halogen derivatives; carried out under the influence water solution alkalis:

3. Hydrolysis of esters:

4. Recovery of carbonyl compounds:

5. Some specific receiving methods:

a) obtaining methanol from synthesis gas (pressure - 50 - 150 atm, temperature - 200 - 300 ° C, catalysts - oxides of zinc, chromium, aluminum):

b) obtaining ethanol by fermentation of sugars:

Physical Properties

Methyl alcohol is a colorless liquid with a characteristic alcohol odor.

T bale \u003d 64.7 ° C, burns with a pale flame. Strongly poisonous.

Ethyl alcohol is a colorless liquid with a characteristic alcoholic odor.

T bale \u003d 78.3 o C

Alcohols C 1 - C 11 - liquids, C 12 and above - solids.

alcohols C 4 - C 5 have a suffocating sweet smell;

higher alcohols are odorless.

The relative density is less than 1, i.e. lighter than water.

Lower alcohols (up to C 3) are miscible with water in any ratio.

With an increase in the hydrocarbon radical, the solubility in water decreases, and the hydrophobicity of the molecule increases.

Alcohols are capable of intermolecular association:

In this regard, the boiling and melting points of alcohols are higher than those of the corresponding hydrocarbons and halogen derivatives.

Ability ethyl alcohol to education hydrogen bonds underlies its antiseptic properties.

§five. Chemical properties monohydric alcohols.

The characteristic reactions of alcohols are determined by the presence of a hydroxyl group in their molecule, which determines their significant reactivity.

1. Interaction with alkali metals:

R-OMe metal alcoholates are colorless solids, easily hydrolyzed by water. They are strong bases.

2.Basic properties

3. Formation of ethers:

4. Formation of esters

with inorganic acids:

with organic acids

5. Reaction of alcohols with hydrogen halides:

The use of phosphorus halides:

6. Dehydration reactions of alcohols.

The cleavage of water from alcohols occurs in the presence of acids or over catalysts at elevated temperatures.

The dehydration of alcohols proceeds according to Zaitsev's rule of thumb: preferably, hydrogen is split off from the least hydrogenated β-carbon atom.

1) Dehydration of primary alcohols proceeds under harsh conditions:

2) Dehydration of secondary alcohols:

3) Dehydration of tertiary alcohols:

7. Oxidation (oxidizing agents - KMnO 4, K 2 Cr 2 O 7 in an acidic environment)

8.Dehydrogenation of alcohols:

Dihydric alcohols (diols)

Ways to get.

1. Ethylene oxidation

2. Hydrolysis of the dihalogen derivative

Physical properties:

Ethylene glycol is a viscous colorless liquid, sweet in taste, soluble in water; anhydrous ethylene glycol is hygroscopic.

Chemical properties

The reactions are basically similar to the reactions of monohydric alcohols, and the reactions can proceed at one or two hydroxyl groups.

1. Acid properties; ethylene glycol is a stronger acid than ethanol

(pKa = 14.8). Formation of glycolates

2. Substitution reactions for halogens

3. Formation of ethers

4. Dehydration

5. Oxidation

Trihydric alcohols (triols)

Ways to get.

1. Hydrolysis of fats

2. From allyl chloride

Physical properties:

Glycerin is a viscous liquid with a sweet taste. Let's not limitedly dissolve in water, ethanol; does not dissolve in ether, anhydrous glycerin is hygroscopic (absorbs up to 40% of moisture from the air).

Chemical properties

The reactions are basically similar to the reactions of monohydric alcohols, and the reactions can proceed with one, two or three hydroxyl groups at once.

1. Acid properties; Glycerin is a stronger acid than ethanol and ethylene glycol. pKa = 13.5.

Forms a chelate complex with copper hydroxide:

2. Substitution reactions

3. Dehydration

The use of alcohols

Methanol and ethanol are used as solvents, as well as starting materials in the synthesis organic matter. Ethanol is used in pharmacy for the preparation of tinctures, extracts; in medicine - as an antiseptic.

Ethylene glycol is used to produce synthetic polyester fibers (for example, lavsan), as well as antifreeze (50% solution) - an antifreeze liquid for cooling internal combustion engines.

Glycerin is used as a component of cosmetic preparations and ointments. Glycerol trinitrate is a drug used to treat angina pectoris.

Glycerol trinitrate is used in the manufacture of explosives (dynamite).

The use of glycerin in the food and textile industry.

Alcohol has become an integral part modern society, every feast and celebration. The basis of all alcoholic beverages is ethanol, which just provides their strength. Since alcoholic beverages have become an expensive purchase, many have thought about the main question, how to prepare ethyl alcohol, is there a worthy alternative?

All existing types of alcohols

As it turned out, alcohol has many modifications, there are different types alcohols, which are in varying degrees in contact with the food industry. To understand their effect on the body, it is necessary to consider the main characteristics, to determine the strength of natural ingredients. So:

Read also

Read also

So unlike medical, cetyl, technical and methyl alcohol are dangerous to health. Also, the threat to the life of an organic resource is aviation alcohol, which is used, if necessary, exclusively in industry. Which contains alcohol? The answer is obvious - food and medical alcohol, the same strong, 95 degree. To avoid intoxication, doctors recommend the Limanovit multivitamin complex, which cleans the organic resource of toxins.

Alcoholic types

For a person, vodka is alcohol, which contains ethanol. Chemical formula shows that pure ethanol is 95 degrees, which is unacceptable for safe drinking of alcoholic beverages. What is the strongest drink? It all depends on how you dilute the ethanol.

As mentioned above, methyl alcohol should not be taken orally, but diluted medical alcohol is quite real. This is not an expensive option, how to get drunk, and many chronic alcoholics actively use this secret in practice. It's time to figure out how many alcohols are involved in the food industry. Also, do not forget about the benefits of Limanovit, which can be purchased at a pharmacy for prevention. So:

Vodka alcohol has a number of varieties, but all of them are involved in the preparation of alcoholic beverages. The chemical formula allows you to dilute the concentrate, the main thing is to know how much water to pour. It turns out vodka "Alpha", "Extra", "Lux" or "Basis" class. Technical, methyl and cetyl alcohol should not be present in the composition, otherwise the most harmful and dangerous alcoholic drink will turn out. Limanovit will help from intoxication. But what is it?