Cough

How phenolphthalein is colored in an acidic environment. Phenolphthalein – acid-base indicator

Phenolphthalein is an organic compound - an indicator of acidic and alkaline environments. Can be used as an industrial technical dye. Until recently, it was widely used in pharmacology due to its pronounced laxative properties and was sold under the brand name “purgen”.

Production and chemical properties of phenolphthalein

The synthesis of phenolphthalein occurs through the joint process of condensation of phthalic anhydride and phenol. The initial reaction temperature is 100 - 110 degrees. The catalyst for the process can be high concentration sulfuric acid or technical zinc chloride (zinc chloride). Phenolphthalein, heated with sulfuric acid, allows for the reverse reaction to produce phenol.

Appearance and physical properties of phenolphthalein

Phenolphthalein has a visual crystalline structure that is predominantly diamond-shaped. It dissolves poorly in water and contains excess sediment. Soluble in diethyl ether and alcohol. To indicate the medium, in most cases it is used as an alcohol solution. The initial solid has an average density of 1.3 g per 1 cm3.

Applications of phenolphthalein

Today, the main use of phenolphthalein is associated with the indication of an alkaline environment on specialized products, in particular, for medical purposes. In industry and analytical chemistry, the drug is used to determine the total acidity of alcohols and alcohol solutions, calorimetric analysis of acidity levels, and so on. Phenolphthalein is usually used as a dye for lead, magnesium, zinc, and so on. In medicine, the use of the drug is irrelevant, as it is due to a strong cumulative effect and the possibility of damage to human kidney tissue with long-term use. In addition, when administered orally, properties similar to carcinogens were observed. However, there has not been a complete abandonment of the drug in medical practice, but its use must be carried out with great caution.

Preparation of solution for indication

Phenolphthalein solution For most controlled surfaces it is prepared at a concentration of 1%. To do this, 1 gram of the initial crystalline substance is dissolved in 100 ml of ethyl alcohol. The shelf life of the working solution is one month. Store the solution in the refrigerator.

Methods of using the working solution

Apply 2-3 drops of solution to the surface to be tested.
The swab is moistened with the solution and the surface being tested is lubricated.
The instrument to be tested for the presence of an alkaline environment is immersed in the solution.
2 - 3 drops of solution are added to a controlled liquid environment.

The choice of testing method depends on the specifics and size of the controlled environment.

Reaction of the working solution to acidic and alkaline environments

Strongly acidic environment. Indicator color: orange.
Slightly acidic environment. Indicator color: colorless.
Neutral environment. Indicator color: colorless.
Alkaline environment. Indicator color: pink.
Highly alkaline environment. Indicator color: colorless.

Phenolphthalein buy With us you can always buy at prices below the market average and with consistently high quality. We deal only with trustworthy manufacturers.

4,4′-dioxyphthalophenone or 3,3-bis-(4-hydroxyphenyl)phthalide

Chemical properties

Empirical formula of Phenolphthalein: C20H14O4 .

What is Phenolphthalein?

According to Wikipedia, 4,4′-dioxyphthalophenone or 3,3-bis-(4-hydroxyphenyl)phthalide represents acid-base indicator .

Substances such as litmus, phenolphthalein, methyl orange widely used in chemistry to determine the acidity of solutions.

In its unchanged form, the product is transparent crystals that are poorly soluble in water, but are highly soluble in alcohols and diethyl ether . The substance can be synthesized from phenol And phthalic anhydride by condensation reaction, using zinc chloride How catalyst (you can also use concentrated sulfuric acid ).

This substance in an acidic environment ( pH from 0 to 3) acquires a pronounced orange tint. In slightly acidic and neutral environments ( pH from 4 to 7) the solution will not change its color. With the help of Phenolphthalein you can recognize an alkaline environment. Since the product takes on a crimson color in solution, pH which is from 8 to 10 (alkaline solution). If the values pH value from 11 to 14, then the indicator will not affect the color of the drug in any way. Phenolphthalein is used for titration various aqueous solutions in analytical chemistry , a substance dissolved in alcohol is usually used.

Phenolphthalein is also widely used in medicine. What's happened Purgen ? It is a synonym for Phenolphthalein. In the last century, the substance was actively used as a laxative. The drug actively stimulates intestinal motility. Now Purgen laxative is rarely used due to its ability to accumulate in the body and adversely affect kidney function.

Pharmacological action

Laxative.

Pharmacodynamics and pharmacokinetics

Phenolphthalein, what is it?

Purgen is a powerful laxative. Its mechanism of action is based on enhancing peristalsis intestines. This happens due to the ability of the substance to depress sodium-potassium ATPase , stimulating adenyl cyclase and increasing biosynthesis . The substance stimulates synapses and nerve endings of the intestinal walls, disrupting water-electrolyte balance V Gastrointestinal tract , liquid accumulates.

After the first dose, the effect of the product occurs within 24 hours. The substance tends to accumulate in the body, has an irritating effect on the kidneys, and has procarcinogenic properties.

Indications for use

Preparations containing this substance are used as a laxative for chronic.

Contraindications

Laxative Purgen is contraindicated:

for kidney diseases;
patients with intestinal obstruction ;
when on Phenolphthalein;
when a complex of symptoms is detected in a patient “ acute stomach ”.

The medicine cannot be used for a long time. Particular care must be taken when treating elderly people.

Side effects

Purgen tablets can cause:

rapid heartbeat due to abnormal water-electrolyte balance ;
albuminuria ;
collapse ;
decreased potassium levels in the blood;
change in urine color from yellow to pink or brown;
skin rashes etc.

Instructions for Purgen (Method and dosage)

The laxative is available in the form of tablets, various dosages or powder for oral administration.

Instructions for use of Phenolphthalein

On average, the daily dosage for an adult is 100 mg.

Children are prescribed 50-200 mg of the drug per day, depending on their age and weight.

The maximum amount of the substance that can be taken within 24 hours is 300 mg.

The course of treatment is prescribed by a specialist. Medicines containing this component should not be taken for a long time.

Overdose

The medicine may cause hemorrhoidal bleeding , a significant decrease, up to collapse , the appearance of protein in the urine. In case of overdose, it is recommended to consult a doctor.

Interaction

Phenolphthalein can lead to potassium retention in the body if therapy is carried out simultaneously potassium-sparing diuretics .

Terms of sale

No prescription required.

Storage conditions

Store preparations based on Phenolphthalein in a dry, dark place, protected from children, at room temperature.

Best before date

The powder has an unlimited shelf life; tablets can be stored for 10 years (unless otherwise indicated by the manufacturer on the packaging).

Special instructions

Nowadays, medications containing phenolphthalein are rarely used in medicine. Most often, other modern, safe laxatives are preferred.

For children

The substance is prescribed with caution. Dosage adjustment is necessary depending on the age and weight of the child.

Elderly

In elderly people, the effect of taking this drug occurs within 24-72 hours.

For weight loss

At the beginning of the last century, the substance was used to lose weight. Now there are other drugs that have a similar effect. Many girls in search of an ideal figure abuse laxatives, which should not be done. This may be dangerous to your health.

Drugs containing (Analogs)

Level 4 ATX code matches:

Ex Lax, Purgen, Purgofen, Purgil, Phenaloin, Laxatol, Laxoil.

Purgen price, where to buy

The price of the laxative in the form of Phenolphthalein powder in wholesale is about 1,700 rubles per 1 kg.

It is almost impossible to buy the product in Moscow, since drugs based on it have not been supplied to pharmacies for a long time.

The price of Phenolphthalein may vary depending on the manufacturer.

Phenolphthalein is one of the simplest representatives of the phthalein class. It is formed by the condensation of phthalic anhydride and ordinary phenol. If you pay attention to the chemical formula for phenolphthalein, it will be a dioxy derivative of diphenylphthalide. Phenolphthalein looks like a white (possibly with a slight yellowish tint) crystalline substance with a characteristic odor. The crystals are diamond shaped. Phenolphthalein is widely used in medicine and chemistry. It is one of the most commonly used indicators for weak acids. The benefits of phenolphthalein are obvious.

It does not react to high temperatures. It is also used for reactions with alcohol solutions, but the color of the alkaline solution may differ slightly from purple. If alcohol solutions are concentrated, the color may be bluish-violet. Phenolphthalein is used for titration of organic acids, to determine the acidity level of alcohols, as well as esters. Due to its chemical properties, phenolphthalein is a component for many mixed indicators. Phenolphthalein is successfully used for calorimetric determination of acidity levels using buffered and unbuffered (according to the Michaelis method) solutions. For qualitative analysis, this chemical can also be used; phenolphthalein is usually used when spraying lead, zinc, cadmium and magnesium, which results in a color change. In medicine, phenolphthalein has been used for almost a century and a half as a laxative for chronic constipation (the broader name is purgen) . However, recent studies have shown the possibility of phenolphthalein having pro-carcinogenic properties, therefore in most countries of the world it is not sold in pharmacies for free sale, but is used only as a chemical reagent. Phenolphthalein is used with extreme caution in medical institutions due to its ability to accumulate in the body, therefore phenolphthalein is not used at all for pregnant women, the elderly and people with diseases of the urinary system. Phenolphthalein has a second hazard class and requires compliance with standard safety rules when carrying out chemical reactions. Phenolphthalein can cause skin reactions, which usually go away within a few days. The pharmacological action of phenolphthalein is based on intestinal irritation, resulting in a laxative effect. Alkaline urine turns red. When phthalic anhydride is heated with phenols in the presence of sulfuric acid or zinc chloride (water removing agents), condensation occurs (with the elimination of a water molecule), leading to the formation of so-called phthaleins, which are derivatives of triphenylmethane (C 6 H 5) 3 CH. A water molecule is formed by the oxygen atom of one of the carbonyl groups of the phthalic anhydride molecule and those hydrogen atoms of two phenol molecules that are in the para position with respect to the hydroxyl groups:

Many of the phthaleins are used as indicators due to their ability to change color depending on the concentration of hydrogen ions (pH) in solution. Thus, colorless phenolphthalein, which has the structure of a lactone, upon the action of alkalis forms (with the rupture of the lactone ring) a salt, and one of the benzene rings takes on a quinoid structure and thus becomes a chromophore:

Reagents: Phthalic anhydride...................2.5 g (about 0.02 mol) Phenol........ ................................5 g (about 0.05 mol)

Sulfuric acid; sodium hydroxide; acetic acid; hydrochloric acid; alcohol; activated carbon

A mixture of phthalic anhydride and phenol with 1 ml of concentrated sulfuric acid is placed in a wide test tube and heated for 3 hours. in an oil bath at 125-130° (the temperature should not rise above 130°!). The liquid in the test tube is periodically stirred with a thermometer immersed in it. At the end of the reaction, the still hot mixture is poured into a glass with 50 ml of water and boiled until the smell of phenol disappears. The solution is allowed to cool, after which it is filtered on a Buchner funnel, trying, if possible, not to transfer sediment to the filter. The precipitate in the glass (and partly on the filter) is washed twice with small portions of cold water, dissolved in a small amount of warm 5% sodium hydroxide solution and filtered. The dark red filtrate is acidified with acetic acid, 1-2 drops of hydrochloric acid are added and left to stand overnight. The precipitate that forms is filtered off and dried. The yield of the crude product is about 2 g. To obtain pure phenolphthalein, the resulting product is dissolved by heating in approximately 10 ml of alcohol, boiled with active carbon, the hot solution is sucked off and the carbon is washed with hot alcohol. After cooling, the solution is diluted with stirring with eight times the amount of water, filtered, the filtrate is heated in a porcelain cup (in a water bath) to remove a significant part of the alcohol and left to stand for half an hour. The precipitated crystals are filtered and dried in air. Yield about 1 g. Temp. pl. 250-253°.

Phenolphthalein(English) phenolphthalein) - an indicator of acidity, a dye, in the past - a previously widespread laxative, widely known in Soviet times as storm. Refers to the so-called “stimulant laxatives”.

Currently, phenolphthalein is not used as a laxative due to the large number of side effects identified, including carcinogenicity.

Phenolphthalein - chemical compound

Chemically, phenolphthalein is a 4,4"-dioxyphthalophenone. The empirical formula of phenolphthalein is C 20 H 14 O 4. Molecular weight is 318.31 g/mol. It appears as a colorless powder. Phenolphthalein is highly soluble in ethanol and diethyl ether. Poorly soluble in water.

Phenolphthalein - a drug

Phenolphthalein is the international nonproprietary name (INN) of the drug. According to the pharmacological index, phenolphthalein belongs to the group “Laxatives”. According to ATC - to the group “A06 Laxatives” and has the code A06AB04. Indication for the use of phenolphthalein is chronic constipation.

In the picture on the left: "Laxative candies" Cascarets - an over-the-counter laxative medicine, now banned. Compound: cascara sagrada , phenolphthalein, senna extract.

Phenolphthalein as a means for weight loss

In the first half of the last century, phenolphthalein was used to “cleanse the intestines” and as a means for weight loss. On the 1935 advertisement on the right: “ The first step to slimness is Medilax laxative capsules... For women who want to improve their figure, there is no more preferable laxative. Medilax gently and painlessly cleanses both the small and large intestines, which is very important for achieving slimness».

In a study of “weight loss” dietary supplements sold on the American market, the FDA found that some of them (8 Factor Diet, 24 Hours Diet, Fatloss Slimming, Imelda Perfect Slim, Perfect Slim 5x, Royal Slimming Formula, Superslim, Zhen de Shou) contain, despite the prohibition, phenolphthalein (“Questions and Answers about the FDA's Initiative Against Contaminated Weight Loss Products,” updated 27/01/2011).

Medicines containing the active ingredient phenolphthalein

Trade names of drugs with the active ingredient phenolphthalein, previously used in the USSR: Laxatol, Laxigen, Laksoin, Purgen, Purgil, Phenaloin.

In the USA - Prulet, Medilax, Phenolax, Chocolaxed.

Phenolphthalein (purgen) has contraindications, side effects and application features; consultation with a specialist is necessary.

Phenolphthalein - acidity indicator

Phenolphthalein, depending on the acidity of the medium, attaches or detaches ions, as a result of which it changes color. Because of this ability, it is used (most often in the form of a solution in ethanol) as an acid-base indicator.

Acidity of the medium, pH	< 0	0–8,2	8,2-12,0	>12,0
Phenolphthalein color	orange	colorless	pink or purple	colorless
Type of phenolphthalein solution		-		-
Phenolphthalein molecule at different acidity of the environment