This term has other meanings, see Lead acetate.
| Lead acetate(II) | |
| Are common | |
| Systematic name | lead acetate, lead acetate(II) |
| Traditional names | lead sugar, lead acetate(2+) |
| Chem. formula | (3)2 |
| Rat. formula | PbC4H6O4 |
| Physical properties | |
| State | hard |
| Molar mass | 325.28, trihydrate 379.33 g/mol |
| Density | 3.25, trihydrate 2.55 g/cm³ |
| Thermal properties | |
| Temperature | |
| • melting | 280 °C |
| Enthalpy | |
| • education | -960.90, trihydrate -1848.6 kJ/mol |
| Chemical properties | |
| Solubility | |
| • in water | 29.3 (10°С), 55.2 (25°С), 221.0 (50°С) |
| • V | highly soluble in acetic acid, methanol, glycerin |
| Classification | |
| Reg. CAS number | 6080-56-4 |
| PubChem | 16685321 |
| Reg. EINECS number | 206-104-4 |
| SMILES | CC(=O)O[Pb]OC(=O)C |
| InChI | InChI=1S/2C2H4O2.Pb/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 GUWSLQUAAYEZAF-UHFFFAOYSA-L |
| RTECS | OF8050000 |
| ChEBI | 31767 |
| ChemSpider | 8956 |
| Safety | |
| Limit concentration | 0.01 mg/m³ |
| LD50 | 100 mg/kg |
| Toxicity | toxic, carcinogenic |
| ECB Pictograms | |
| NFPA 704 | 0 3 0 |
| Data given is based on standard conditions (25 °C, 100 kPa) unless otherwise stated. | |
| Media files on Wikimedia Commons | |
Lead(II) acetate
(lead acetate, lead acetate (2+)) - an organic chemical compound, lead salt of acetic acid. Chemical formula: (3)2. Forms crystalline hydrates: (3)2·3H2O (lead sugar) and (3)2·10H2O.
Under normal conditions it appears as transparent crystals. The trihydrate has a sweet taste, but, like many other lead compounds, is toxic.
Receipt
Lead(II) acetate is prepared by reacting acetic acid with lead(II) oxide or carbonate:
P b O + 2 CH 3 COOH → P b ( CH 3 COO ) 2 + H 2 O {\displaystyle {\mathsf {PbO+2CH_{3}COOH{\xrightarrow {\ \ }}\ Pb(CH_{3} COO)_{2}+H_{2}O}}} P b CO 3 + 2 CH 3 COOH → P b ( CH 3 COO ) 2 + H 2 O + CO 2 ↑ {\displaystyle {\mathsf {PbCO_{ 3}+2CH_{3}COOH{\xrightarrow {\ \ }}\ Pb(CH_{3}COO)_{2}+H_{2}O+CO_{2}\uparrow }}}
Synthesis of lead acetate: metal lead is placed in a heat-resistant glass and filled with nitric acid, during which lead nitrate is formed, which has a pale yellowish color. This mixture is poured with hot water and, after the lead nitrate has dissolved, filtered using a funnel with a paper or cotton filter. Sodium or potassium hydroxide is added to the resulting solution, resulting in a precipitate that settles, washed with water, settles again, the excess liquid is drained, and a white precipitate of lead hydroxide remains, which is filled with acetic acid until the precipitate is completely dissolved. This mixture is evaporated to obtain a concentrated solution and placed in a cool place - lead acetate crystals gradually form and precipitate in it.
When a solution of lead (II) acetate is evaporated, crystals of trihydrate (3)2·3H2O precipitate. To obtain crystals of anhydrous lead acetate, it is necessary to carry out evaporation with a large excess of acetic acid.
An excerpt characterizing Lead(II) Acetate
In different corners of Moscow people were still moving senselessly, keeping old habits and not understanding what they were doing. When it was announced to Napoleon with due caution that Moscow was empty, he looked angrily at the person who reported this and, turning away, continued to walk in silence. “Bring the carriage,” he said. He got into the carriage next to the adjutant on duty and drove to the suburbs. - “Moscow deserte. Quel evenemeDt invraisemblable!” [“Moscow is empty. What an incredible event!”] he said to himself. He did not go to the city, but stopped at an inn in the Dorogomilovsky suburb. Le coup de theater avait rate. [The end of the theatrical performance failed.] Russian troops passed through Moscow from two o'clock in the morning until two o'clock in the afternoon and carried away with them the last residents and wounded who were leaving. The biggest crush during the movement of troops occurred on the Kamenny, Moskvoretsky and Yauzsky bridges. While, bifurcated around the Kremlin, the troops crowded onto the Moskvoretsky and Kamenny bridges, a huge number of soldiers, taking advantage of the stop and crowded conditions, returned from the bridges and stealthily and silently snuck past St. Basil's and under the Borovitsky Gate back up the hill to Red Square, on which, by some instinct, they felt that they could easily take someone else’s property. The same crowd of people, as if for cheap goods, filled Gostiny Dvor in all its passages and passages. But there were no tenderly sugary, alluring voices of the hotel guests, there were no peddlers and a motley female crowd of buyers - there were only the uniforms and greatcoats of soldiers without guns, silently leaving with burdens and entering the ranks without burdens. Merchants and peasants (there were few of them), as if lost, walked among the soldiers, unlocked and locked their shops, and themselves and the fellows carried their goods somewhere. Drummers stood on the square near Gostiny Dvor and beat the collection. But the sound of the drum forced the robber soldiers not, as before, to run to the call, but, on the contrary, forced them to run further away from the drum. Between the soldiers, along the benches and aisles, people in gray caftans and with shaved heads could be seen. Two officers, one in a scarf over his uniform, on a thin dark gray horse, the other in an overcoat, on foot, stood at the corner of Ilyinka and talked about something. The third officer galloped up to them. “The general ordered everyone to be expelled now at any cost.” What the hell, it doesn't look like anything! Half the people fled. “Where are you going?.. Where are you going?” he shouted at three infantry soldiers who, without guns, having picked up the skirts of their greatcoats, slipped past him into the ranks. - Stop, rascals! - Yes, please collect them! - answered another officer. – You can’t collect them; we have to go quickly so that the last ones don’t leave, that’s all! - How to go? they stood there, huddled on the bridge and didn’t move. Or put a chain so that the last ones don’t run away? - Yes, go there! Get them out! - the senior officer shouted. The officer in the scarf got off his horse, called the drummer and went with him under the arches. Several soldiers began to run in a crowd. The merchant, with red pimples on his cheeks near his nose, with a calmly unshakable expression of calculation on his well-fed face, hastily and dapperly, waving his arms, approached the officer. “Your honor,” he said, “do me a favor and protect me.” It’s not a small matter for us, it’s our pleasure! Please, I’ll take out the cloth now, at least two pieces for a noble man, with our pleasure! Because we feel, well, this is just robbery! You're welcome! They should have put a guard there, or at least let them lock him up... Several merchants crowded around the officer. - Eh! it's a waste of time to lie! - said one of them, thin, with a stern face. “When you take off your head, you don’t cry over your hair.” Take whatever you like! “And he waved his hand with an energetic gesture and turned sideways to the officer. “It’s good for you, Ivan Sidorich, to speak,” the first merchant spoke angrily. - You are welcome, your honor. - What should I say! – the thin man shouted. “I have a hundred thousand goods in three shops here.” Can you save it when the army has left? Eh, people, God’s power cannot be broken by hands! “Please, your honor,” said the first merchant, bowing. The officer stood in bewilderment, and indecision was visible on his face. - What do I care! - he suddenly shouted and walked with quick steps forward along the row. In one open shop, blows and curses were heard, and while the officer was approaching it, a man in a gray overcoat and with a shaved head jumped out of the door. This man, bending over, rushed past the merchants and the officer. The officer attacked the soldiers who were in the shop. But at that time, terrible screams of a huge crowd were heard on the Moskvoretsky Bridge, and the officer ran out onto the square. - What's happened? What's happened? - he asked, but his comrade was already galloping towards the screams, past St. Basil the Blessed. The officer mounted and rode after him. When he arrived at the bridge, he saw two cannons removed from their limbers, infantry walking across the bridge, several fallen carts, several frightened faces and the laughing faces of soldiers. Near the cannons stood one cart drawn by a pair. Behind the cart, four greyhounds in collars huddled behind the wheels. There was a mountain of things on the cart, and at the very top, next to the children's chair, a woman was sitting upside down, screaming shrilly and desperately. The comrades told the officer that the scream of the crowd and the squeals of the woman occurred because General Ermolov, who drove into this crowd, having learned that the soldiers were scattering among the shops and crowds of residents were blocking the bridge, ordered the guns to be removed from the limbers and an example was made that he would shoot at the bridge . The crowd, knocking down the carts, crushing each other, screaming desperately, crowding in, cleared the bridge, and the troops moved forward. Meanwhile, the city itself was empty. There was almost no one on the streets. The gates and shops were all locked; here and there near the taverns lonely screams or drunken singing were heard. No one drove along the streets, and pedestrian footsteps were rarely heard. On Povarskaya it was completely quiet and deserted. In the huge courtyard of the Rostovs' house there were scraps of hay and droppings from a transport train, and not a single person was visible. In the Rostov house, which was left with all its good things, two people were in the large living room. These were the janitor Ignat and the Cossack Mishka, Vasilich’s grandson, who remained in Moscow with his grandfather. Mishka opened the clavichord and played it with one finger. The janitor, arms akimbo and smiling joyfully, stood in front of a large mirror. - That’s clever! A? Uncle Ignat! - the boy said, suddenly starting to clap the keys with both hands. - Look! - Ignat answered, marveling at how his face smiled more and more in the mirror. - Shameless! Really, shameless! – the voice of Mavra Kuzminishna, who quietly entered, spoke from behind them. - Eka, thick-horned, he bares his teeth. Take you on this! Everything there is not tidy, Vasilich is knocked off his feet. Give it time! Ignat, adjusting his belt, stopped smiling and submissively lowered his eyes, walked out of the room. “Auntie, I’ll go easy,” said the boy. - I'll give you a light one. Little shooter! – Mavra Kuzminishna shouted, raising her hand at him. - Go and set up a samovar for grandfather. Mavra Kuzminishna, brushing off the dust, closed the clavichord and, sighing heavily, left the living room and locked the front door. Coming out into the courtyard, Mavra Kuzminishna thought about where she should go now: should she drink tea in Vasilich’s outbuilding or tidy up what had not yet been tidied up in the pantry? Quick steps were heard in the quiet street. The steps stopped at the gate; the latch began to knock under the hand that was trying to unlock it. Mavra Kuzminishna approached the gate. - Who do you need? - Count, Count Ilya Andreich Rostov. - Who are you? - I'm an officer. “I would like to see,” said the Russian pleasant and lordly voice. Mavra Kuzminishna unlocked the gate. And a round-faced officer, about eighteen years old, with a face similar to the Rostovs, entered the courtyard. - We left, father. “We deigned to leave at vespers yesterday,” Mavra Kuzmipishna said affectionately. The young officer, standing at the gate, as if hesitant to enter or not to enter, clicked his tongue. “Oh, what a shame!..” he said. - I wish I had yesterday... Oh, what a pity!..
Physical properties
Forms colorless transparent crystals. Anhydrous lead acetate melts at 280 °C with partial sublimation and decomposition into Pb, CO2, H2O and acetone.
The most studied is lead acetate trihydrate. It forms colorless transparent crystals, which at 75 °C melt in their own water of crystallization, and at 100 °C they begin to decompose (most likely hydrolysis). Lead acetate trihydrate crystals belong to the monoclinic system, space group C 2/m, unit cell parameters a
= 1.585 nm,
b
= 0.730 nm,
c
= 0.910 nm, α = 109.8.
Chemical properties
Analytical reactions for lead acetate
Qualitative reactions determine the presence of lead (II) ions:
- the reaction with potassium iodide gives a yellow (golden) precipitate, which partially dissolves when heated and again precipitates in the form of golden plates when the solution is cooled (golden rain):
P b ( CH 3 COO ) 2 + 2 KI → P b I 2 ↓ + 2 CH 3 COOK {\displaystyle {\mathsf {Pb(CH_{3}COO)_{2}+2KI{\xrightarrow {\ \ } }\PbI_{2}\downarrow +2CH_{3}COOK}}}
- reaction with hydrogen sulfide water to form a black precipitate of lead sulfide:
P b ( CH 3 COO ) 2 + H 2 S → P b S ↓ + 2 CH 3 COOH {\displaystyle {\mathsf {Pb(CH_{3}COO)_{2}+H_{2}S{\xrightarrow {\ \ }}\PbS\downarrow +2CH_{3}COOH}}}
Content
- 1 Historical information
- 2 Receipt
- 3 Physical properties
- 4 Chemical properties 4.1 Analytical reactions for lead acetate
- 5.1 In medicine
- 6.1 Symptoms of acute poisoning
Application
Currently, lead acetate is used in analytical chemistry, dyeing, calico printing, as a silk filler and for the production of other lead compounds. In the past it was used in cosmetics, but due to its high toxicity it was banned.
In medicine
In medicine, an aqueous solution of lead acetate, the so-called “lead water” or “lead lotion” was previously used as an external anti-inflammatory and astringent [1]. At the moment, lead acetate is practically not used in clinical practice. Teymurov's paste is part of the Russian pharmaceutical preparation.
Uses [edit]
Sweetener[edit]
Like other lead(II) salts, lead(II) acetate has a sweet taste, which led to its historical use as a sugar substitute in both wines and foods. [7] [8] The ancient Romans, who had few sweeteners other than honey, boiled must (grape juice) in lead pots to produce a reduced sugar syrup called defrutum
, again concentrated into
sapa
. This syrup was used to sweeten wine and to sweeten and preserve fruit. It is possible that lead(II) acetate or other lead compounds found in the syrup could cause lead poisoning in those who consumed it. [9]Lead acetate is no longer used in the production of sweeteners due to its recognized toxicity. Modern chemistry can easily detect it, which has almost completely stopped illegal use, which continued for decades after legal use as a sweetener was banned. [10]
Historical incidents[edit]
The earliest confirmed lead acetate poisoning was that of Pope Clement II, who died in October 1047. Toxicology testing of his remains in the mid-20th century confirmed centuries-old rumors that he was poisoned by lead sugar. [11] It is unclear whether he was killed.
In 1787, artist Albert Christophe Dies accidentally ingested approximately 3/4 ounce (20 g) of lead acetate. His recovery from this poison was slow and incomplete. He lived with illnesses until his death in 1822. [12] [13]
Although the use of lead(II) acetate as a sweetener was already illegal at the time, composer Ludwig van Beethoven may have died from lead poisoning caused by wines adulterated with lead acetate (see also Beethoven's liver)
. [14] [15]
In the 1850s, Mary Seacole used lead(II) acetate, among other remedies, against a cholera epidemic in Panama. [16] [17]
In 1887, 38 hunting horses owned by Captain William Hollway Steeds were poisoned in their stables at Clonsilla House, Dublin, Ireland. At least ten hunters died. Captain Steeds, a "large commission agent", had previously supplied horses for trainer Bray and Greystone. It turned out that they were fed bran sweetened with toxic lead acetate. [18]
Cosmetics [edit]
Lead(II) acetate, as well as white lead, has been used in cosmetics throughout history. [19]
Until recently it was still used in the US in men's hair coloring products [20] like Greek formulas. It was only a few years ago that the manufacturer removed lead acetate from the hair color product, and as of July 2021, the ingredients in Grecian Formula are water, isopropyl alcohol, triethanolamine, bismuth citrate, sodium thiosulfate, fragrance and panthenol. Lead acetate was replaced by bismuth citrate as a progressive dye. Its use in cosmetics was banned by Health Canada in 2005 (effective late 2006) based on tests showing possible carcinogenicity and reproductive toxicity [21], and has also been banned in the European Union [21]. listed on California's Proposition 65 warning list as a carcinogen [22].
Medical use[edit]
Lead(II) acetate solution was a common folk remedy for nipple pain. [23] In modern medicine, it was used for a time as an astringent in the form of Goulara extract, and also to treat poison ivy. [24]
Industrial use[edit]
Lead(II) acetate paper is used to detect the poisonous gas hydrogen sulfide. The gas reacts with lead(II) acetate on moistened test paper to form a gray precipitate of lead(II) sulfide.
An aqueous solution of lead(II) acetate is a byproduct of a 1:1 ratio of hydrogen peroxide and white vinegar (acetic acid) used in the cleaning and maintenance of stainless steel firearm suppressors (silencers) and compensators. The solution is stirred by bubbles of hydrogen peroxide, and the main reaction is to dissolve the lead deposits inside the muffler with acetic acid, which forms lead acetate. Due to its high toxicity, this chemical solution must be properly disposed of at a chemical facility or hazardous materials center. Alternatively, the solution can be reacted with sulfuric acid to precipitate the nearly insoluble substances lead(II) sulfate. The solid can then be removed by mechanical filtration and is safer to dispose of than an aqueous solution of lead acetate.
It was also used to make slow matches in the Middle Ages. It was made by mixing a natural form of lead(II) oxide called litharge and vinegar.
Lead sugar was the recommended agent added to linseed oil during heating to produce "boiled" linseed oil, with the lead and heat causing the oil to solidify more quickly than raw linseed oil. [25]
Toxicity
Lead acetate is toxic, neurotoxic and carcinogenic, like all other compounds of this heavy metal. For lead acetate, the MPC is 0.01 mg/m³, semi-lethal dose LD50 for mice: 100 mg/kg.
Symptoms of acute poisoning
Metallic taste in the mouth, abdominal pain, vomiting, diarrhea (black stools), oliguria, collapse, coma.
Symptoms of chronic poisoning
Loss of appetite and weight, constipation, apathy or irritability, fatigue, headache, metallic taste in the mouth, gray border on the gums. More severe intoxication is accompanied by periodic vomiting, loss of coordination, pain in the limbs, joints, sensitivity disorders, paralysis of the extensor muscles of the hand and foot, menstrual irregularities, and miscarriages.
Links
- RK Rajaram and JK Mohana Rao (1982). Crystal structure of lead acetate trihydrate. Zeitschrift für Kristallographie: Vol. 160, No. 3-4, pp. 225-233. (unavailable link)
- Chemical Encyclopedia / Editorial Board: Knunyants I.L. and others. - M.: Soviet Encyclopedia, 1995. - T. 4. - 639 p. — ISBN 5-82270-092-4.
- Ripan R., Ceteanu I.
Inorganic chemistry. Chemistry of metals. - M.: Mir, 1971. - T. 1. - 561 p.
| Lead compounds | |
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