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Ethanal acetaldehyde. Acetic aldehyde. Physical and thermal properties. Receipt and application. Acetic aldehyde as an occupational hazard

192,85 Enthalpy of formation -166 kJ/mol Steam pressure 2.7650; 4.8670; 10.0 100 atm Chemical properties pK a 13.57 (25°C) Solubility in water With water, ethanol is miscible in all proportions. Optical properties Refractive index 1,3316 Structure Dipole moment 2.750±0.006 Classification Reg. CAS number 75-07-0 PubChem 177 Reg. EINECS number 200-836-8 SMILES Reg. EC number 200-836-8 RTECS AB1925000 Security MPC 5 mg/m 3 LD 50 1232 mg/kg (mice, intragastrically),
900 mg/kg (mice, oral),
661 mg/kg (rats, oral) Toxicity toxic, addictive, irritant, carcinogen Data is based on standard conditions (25 °C, 100 kPa) unless otherwise noted.

Acetaldehyde (acetic aldehyde, ethanal, methylformaldehyde) - organic compound the class of aldehydes with the chemical formula CH 3 -CHO, is the aldehyde of ethanol and acetic acid. It is one of the most important aldehydes that occurs widely in nature and is produced in large quantities industrially. Acetaldehyde is found in coffee, ripe fruit, bread, and is synthesized by plants as a result of their metabolism. Also produced by the oxidation of ethanol.

Physical Properties

The substance is a colorless liquid with a pungent odor, readily soluble in water, alcohol, ether. Due to the very low boiling point (20.2 °C), acetaldehyde is stored and transported as a trimer - paraldehyde, from which it can be obtained by heating with mineral acids (usually sulfuric).

Receipt

In 2003, global production was about a million tons per year.

The main production method is the oxidation of ethylene (the Wacker process):

$\mathsf(2CH_2\text(=)CH_2 + O_2 \rightarrow 2CH_3CHO)$

Palladium chloride is used as an oxidizing agent in the Wacker process, which is regenerated by oxidation with copper chloride in the presence of atmospheric oxygen:

$\mathsf(CH_2\text(=)CH_2 + PdCl_2 + H_2O \rightarrow CH_3CHO + Pd + 2HCl)$ $\mathsf(Pd + 2CuCl_2 \rightarrow PdCl_2 + 2CuCl)$ $\mathsf(4CuCl + 4HCl + O_2 \rightarrow 4CuCl_2 + 2H_2O)$

Acetic aldehyde is also obtained by hydration of acetylene in the presence of salts (Kucherov reaction), with the formation of enol, which isomerizes to aldehyde:

$\mathsf(C_2H_2 + H_2O \xrightarrow (Hg^(2+), H^+) CH_3CHO)$

Another method dominated until the discovery of the Wacker process. It consisted in the oxidation or dehydrogenation of ethyl alcohol, on a copper or silver catalyst.

$\mathsf(C_2H_5OH \xrightarrow(Ag, ^oC) CH_3CHO + H_2)$ $\mathsf(2C_2H_5OH + O_2 \xrightarrow(Ag, ^oC) 2CH_3CHO + 2H_2O)$

Reactivity

According to its chemical properties, acetaldehyde is a typical aliphatic aldehyde, and it is characterized by reactions of this class of compounds. Its reactivity is determined by two factors: the activity of the carbonyl of the aldehyde group and the mobility of the hydrogen atoms of the methyl group, due to the inductive effect of the carbonyl.

Like other carbonyl compounds with hydrogen atoms at the α-carbon atom, acetaldehyde tautomerizes, forming enol - vinyl alcohol, the equilibrium is almost completely shifted towards the aldehyde form (the equilibrium constant is only 6 10 −5 at room temperature):

Condensation reaction

Due to its small molecular size and availability as an anhydrous monomer (unlike formaldehyde), acetaldehyde is a widely used electrophilic agent in organic synthesis. In terms of condensation reactions, the aldehyde is prochiral. It is used mainly as a source of the "CH 3 C + H(OH)" synthon in aldol and related condensation reactions. Grignard's reagent and organolithium compounds react with MeCHO to form hydroxyethyl derivatives. In one of the condensation reactions, three equivalents of formaldehyde are added, and one reduces the resulting aldehyde, forming pentaerythritol from MeCHO (C(CH 2 OH) 4 .)

Acetaldehyde is also an important building block for the synthesis of heterocyclic compounds. An outstanding example is the conversion by the action of ammonia to 5-ethyl-2-methylpyridine ("aldehyde-collidine")

The reaction of aldol condensation is due to the mobility of hydrogen in the alpha position in the radical and is carried out in the presence of dilute alkalis. It can be viewed as a reaction of nucleophilic addition of one aldehyde molecule to another:

$\mathsf(CH_3\text(-)CH_2\text(-)CHO + CH_3\text(-)CH_2\text(-)CHO \rightarrow CH_3\text(-)CH_2\text(-)CH(OH)\text (-)CH(CH_3)\text(-)CHO)$

Acetal derivatives

Three molecules of acetaldehyde condense to form "paraldehyde" - a cyclic trimer containing single C-O connection. Condensation of four molecules gives a cyclic compound called metaldehyde.

Acetaldehyde forms stable acetals upon reaction with ethanol under dehydration conditions. The product CH 3 CH(OCH 2 CH 3) 2 is called "acetal", although the term is used to describe a broader group of compounds with the general formula RCH(OR") 2 .

Application

Acetic aldehyde is used to produce acetic acid, butadiene, some organic substances, and aldehyde polymers.

Traditionally, acetaldehyde has mainly been used as a precursor to acetic acid. This application was rejected due to the fact that acetic acid is more efficiently produced from methanol using the Monsanto and Kativa processes. In terms of the condensation reaction, acetaldehyde is an important precursor to the pyridine derivatives, pentaerythrol and crotonaldehyde. Urea and acetaldehyde condense to form resins. Acetic anhydride reacts with acetaldehyde to give ethylidene diacetate, from which vinyl acetate, a monomer of polyvinyl acetate, is obtained.

Biochemistry

Alzheimer's disease

Individuals who lack the genetic factor for converting acetaldehyde to acetic acid may be at high risk of predisposition to Alzheimer's disease. "These results indicate that the absence of ALDH2 is a risk factor for late onset Alzheimer's disease."

The problem of alcohol

Acetaldehyde derived from ingested ethanol binds enzymes, forming adducts associated with organ diseases. The drug disulfiram (Antabuse) prevents the oxidation of acetaldehyde to acetic acid. This gives an unpleasant sensation when taking alcohol. Antabuse is used when the alcoholic wants to be cured.

Carcinogen

Acetaldehyde is a carcinogen of the first group. "There is sufficient evidence of the carcinogenicity of acetaldehyde (the main metabolite of ethanol) in animal experiments", in addition, acetaldehyde damages DNA and causes disproportionate total weight body muscle development associated with a violation of the protein balance of the body. As a result of a study of 818 alcoholics, scientists came to the conclusion that those patients who were exposed to the action of acetaldehyde to a greater extent, there is a defect in the gene for the alcohol dehydrogenase enzyme. Therefore, these patients are at greater risk of developing cancer of the upper GI tract and liver.

Security

Acetaldehyde is toxic to the skin, an irritant, and a carcinogen. However, the toxicity of acetaldehyde is lower than that of formaldehyde, as acetaldehyde is rapidly oxidized in the body to harmless acetic acid. It is also an air pollutant from combustion, smoking, and vehicle exhaust. In addition, ethanal is formed during the heat treatment of polymers and plastics.

Prolonged contact with air can form peroxides and cause an explosion that can destroy the container

Skin: Use of adequate protective clothing to prevent skin contact.
Eyes: Use of adequate eye PPE
Changing clothes: When wet (due to fire hazard)
Recommendations: Install eye wash fountains, equip places for quick changing clothes

The use of RPE

If the MPC is exceeded, it is necessary to use insulating RPE with a constant overpressure under a full-face mask (air supply on demand under pressure, etc.). When using hose respirators, they must be equipped with an auxiliary self-contained breathing apparatus with a constant overpressure under the mask and a service life sufficient to leave the dangerous place in the event of a violation of the air supply through the hose.

For evacuation, filtering RPE with a full-face mask and filters to protect against organic vapors, or an insulating self-rescuer can be used.

Congenital alcohol intolerance

One of the mechanisms of congenital alcohol intolerance is the accumulation of acetaldehyde.

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Notes

Chemical Encyclopedia / Ed.: Knunyants I.L. and others. - M .: Soviet Encyclopedia, 1988. - T. 1. - 623 p.
March, J. "Organic Chemistry: Reactions, Mechanisms, and Structures" J. Wiley, New York: 1992. ISBN 0-471-58148-8.
Sowin, T. J.; Melcher, L. M. "Acetaldehyde" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI:10.1002/047084289
en:Strecker amino acid synthesis
Kendall, E. C. McKenzie, B. F. (1941), "dl-Alanine", Org. synth.; Coll. Vol. 1:21
Wittig, G.; Hesse, A. (1988), "Directed Aldol Condensations: β-Phenylcinnamaldehyde", Org. synth.; Coll. Vol. 6:901
Frank, R. L.; Pilgrim, F. J.; Riener, E. F. (1963), "5-Ethyl-2-Methylpyridine", Org. synth.; Coll. Vol. 4:451
Adkins, H.; Nissen, B. H. (1941), "Acetal", Org. synth.; Coll. Vol. eleven
en:Monsanto process
en:Cativa process
NAD+ to NADH Hipolito, L.; Sanchez, M. J.; Polache, A.; Granero, L. Brain metabolism of ethanol and alcoholism: An update. Curr. drug metab. 2007, 8, 716-727
"Mitochondrial ALDH2 Deficiency as an Oxidative Stress". Annals of the New York Academy of Sciences 1011: 36-44. April 2004. doi:10.1196/annals.1293.004. PMID 15126281. Retrieved 2009-08-13.
Nakamura, K.; Iwahashi, K.; Furukawa, A.; Ameno, K.; Kinoshita, H.; Ijiri, I.; Sekine, Y.; Suzuki, K.; Iwata, Y.; Minabe, Y.; Mori, N. Acetaldehyde adducts in the brain of alcoholics. Arch. Toxicol. 2003, 77, 591.
(Press release). International Agency for Research on Cancer (IARC). - November 2, 2009 -- IARC has updated the cancer assessments of several personal habits and household exposures that cause cancer, including tobacco, areca nut, alcohol, and household coal smoke. The update was conducted with the advice of 30 scientists from 10 countries who met at IARC in October 2009. [...] The Working Group concluded that acetaldehyde associated with alcohol consumption is carcinogenic to humans (Group 1) and confirmed the classification in Group 1 of alcohol consumption and of ethanol in alcoholic beverages. Retrieved 1 August 2014.
Chemical Summary For Acetaldehyde, US Environmental Protection Agency
^ Nicholas S. Aberle, II, Larry Burd, Bonnie H. Zhao and Jun Ren (2004). "Acetaldehyde-induced cardiac contractile dysfunction may be alleviated by vitamin B1 but not by vitamins B6 or B12". Alcohol & Alcoholism 39(5): 450-454. doi:10.1093/alcalc/agh085.
Nils Homann, Felix Stickel, Inke R. König, Arne Jacobs, Klaus Junghanns, Monika Benesova, Detlef Schuppan, Susanne Himsel, Ina Zuber-Jerger, Claus Hellerbrand, Dieter Ludwig, Wolfgang H. Caselmann, Helmut K. Seitz Alcohol dehydrogenase 1C* 1 allele is a genetic marker for alcohol-associated cancer in heavy drinkers International Journal of Cancer Volume 118, Issue 8, Pages 1998-2002
smoking. (2006). Encyclopædia Britannica. Accessed 27 Oct 2006.
/ Michael E. Barsan (technical editor). - NIOSH. - Cincinnati, Ohio, 2007. - S. 2. - 454 p. - (DHHS (NIOSH) Publication No. 2005-149).



Limit

Unlimited

aromatic

Heterocyclic

An excerpt characterizing Acetaldehyde

While the sovereign was approaching one flank of the battalions, which had made guard duty, another crowd of horsemen jumped to the opposite flank, and ahead of them Rostov recognized Napoleon. It couldn't be anyone else. He rode at a gallop in a small hat, with St. Andrew's ribbon over his shoulder, in a blue uniform open over a white camisole, on an unusually thoroughbred Arabian gray horse, on a crimson, gold embroidered saddle. Riding up to Alexander, he raised his hat, and with this movement, the cavalry eye of Rostov could not fail to notice that Napoleon was badly and not firmly sitting on his horse. The battalions shouted: Hooray and Vive l "Empereur! [Long live the Emperor!] Napoleon said something to Alexander. Both emperors got off their horses and took each other's hands. Napoleon had an unpleasantly fake smile on his face. Alexander with an affectionate expression said something to him .
Rostov did not take his eyes off, despite the trampling by the horses of the French gendarmes, besieging the crowd, followed every movement of Emperor Alexander and Bonaparte. As a surprise, he was struck by the fact that Alexander behaved as an equal with Bonaparte, and that Bonaparte was completely free, as if this closeness with the sovereign was natural and familiar to him, as an equal, he treated the Russian Tsar.
Alexander and Napoleon with a long tail of retinue approached the right flank of the Preobrazhensky battalion, right on the crowd that was standing there. The crowd unexpectedly found itself so close to the emperors that Rostov, who was standing in the front ranks of it, became afraid that they would not recognize him.
- Sire, je vous demande la permission de donner la legion d "honneur au plus brave de vos soldats, [Sir, I ask you for permission to give the Order of the Legion of Honor to the bravest of your soldiers,] - said a sharp, precise voice, finishing each letter This was said by Bonaparte, small in stature, looking directly into Alexander's eyes from below.
- A celui qui s "est le plus vaillament conduit dans cette derieniere guerre, [To the one who showed himself the most bravely during the war,]" Napoleon added, rapping out each syllable, with outrageous calmness and confidence for Rostov, looking around the ranks of the Russians stretched out in front of him soldiers, keeping everything on guard and looking motionlessly into the face of their emperor.
- Votre majeste me permettra t elle de demander l "avis du colonel? [Your Majesty will allow me to ask the colonel's opinion?] - Alexander said and took a few hasty steps towards Prince Kozlovsky, the battalion commander. Meanwhile, Bonaparte began to take off his white glove, small hand and tearing it, he threw it in. The adjutant, hastily rushing forward from behind, picked it up.
- To whom to give? - not loudly, in Russian, Emperor Alexander asked Kozlovsky.
- Whom do you order, Your Majesty? The sovereign grimaced with displeasure and, looking around, said:
“Yes, you have to answer him.
Kozlovsky looked back at the ranks with a resolute look, and in this look captured Rostov as well.
“Is it not me?” thought Rostov.
- Lazarev! the colonel commanded, frowning; and the first-ranking soldier, Lazarev, briskly stepped forward.
– Where are you? Stop here! - voices whispered to Lazarev, who did not know where to go. Lazarev stopped, glancing fearfully at the colonel, and his face twitched, as happens with soldiers called to the front.
Napoleon slightly turned his head back and pulled back his small plump hand, as if wanting to take something. The faces of his retinue, guessing at the same moment what was the matter, fussed, whispered, passing something to one another, and the page, the same one whom Rostov had seen yesterday at Boris, ran forward and respectfully leaned over the outstretched hand and did not make her wait for a single moment. one second, put an order on a red ribbon into it. Napoleon, without looking, squeezed two fingers. The Order found itself between them. Napoleon approached Lazarev, who, rolling his eyes, stubbornly continued to look only at his sovereign, and looked back at Emperor Alexander, showing by this that what he was doing now, he was doing for his ally. A small white hand with an order touched the button of the soldier Lazarev. It was as if Napoleon knew that in order for this soldier to be happy, rewarded and distinguished from everyone else in the world forever, it was only necessary that Napoleon’s hand deign to touch the soldier’s chest. Napoleon only put the cross on Lazarev's chest and, letting go of his hand, turned to Alexander, as if he knew that the cross should stick to Lazarev's chest. The cross really stuck.
Helpful Russian and French hands, instantly picking up the cross, attached it to the uniform. Lazarev looked gloomily at little man, with white hands, who did something over him, and continuing to hold him motionless on guard, again began to look directly into Alexander's eyes, as if he was asking Alexander: is he still standing, or will they order him to walk now, or maybe do anything else? But nothing was ordered to him, and he remained in this motionless state for quite some time.
The sovereigns sat on horseback and left. The Preobrazhenians, upsetting their ranks, mingled with the French guards and sat down at the tables prepared for them.
Lazarev was sitting in a place of honor; he was embraced, congratulated and shook hands by Russian and French officers. Crowds of officers and people came up just to look at Lazarev. The buzz of Russian French and laughter stood in the square around the tables. Two officers with flushed faces, cheerful and happy, walked past Rostov.
- What, brother, treats? Everything is in silver,” said one. Have you seen Lazarev?
- Saw.
- Tomorrow, they say, the Preobrazhensky people will treat them.
- No, Lazarev is so lucky! 10 francs for life pension.
- That's the hat, guys! shouted the Preobrazhensky, putting on a Frenchman's shaggy hat.
- A miracle, how good, lovely!
Did you hear the feedback? said the Guards officer to another. The third day was Napoleon, France, bravoure; [Napoleon, France, courage;] yesterday Alexandre, Russie, grandeur; [Alexander, Russia, greatness;] one day our sovereign gives a review, and the other day Napoleon. Tomorrow the sovereign will send George to the bravest of the French guards. It's impossible! Should answer the same.
Boris and his comrade Zhilinsky also came to see the Preobrazhensky banquet. Returning back, Boris noticed Rostov, who was standing at the corner of the house.
- Rostov! Hi; we didn’t see each other,” he told him, and could not help asking him what had happened to him: Rostov’s face was so strangely gloomy and upset.
“Nothing, nothing,” replied Rostov.
– Will you come?
- Yes, I will.
Rostov stood at the corner for a long time, looking at the feasters from afar. A painful work was going on in his mind, which he could not bring to the end. Terrible doubts arose in my heart. Then he remembered Denisov with his changed expression, with his humility, and the whole hospital with those torn off arms and legs, with this dirt and disease. It seemed to him so vividly that he now felt this hospital smell of a dead body that he looked around to understand where this smell could come from. Then he remembered this self-satisfied Bonaparte with his white pen, who was now the emperor, whom the emperor Alexander loves and respects. What are the severed arms, legs, murdered people for? Then he remembered the awarded Lazarev and Denisov, punished and unforgiven. He found himself thinking such strange thoughts that he was afraid of them.
The smell of Preobrazhensky food and hunger brought him out of this state: he had to eat something before leaving. He went to the hotel he had seen in the morning. In the hotel, he found so many people, officers, who, like him, arrived in civilian clothes, that he hardly managed to get dinner. Two officers from the same division as him joined him. The conversation naturally turned to the world. The officers, comrades of Rostov, like most of the army, were dissatisfied with the peace concluded after Friedland. They said that if they could hold on, Napoleon would have disappeared, that he had no crackers or charges in his troops. Nicholas ate in silence and mostly drank. He drank one or two bottles of wine. The inner work that arose in him, not being resolved, still tormented him. He was afraid to indulge in his thoughts and could not get behind them. Suddenly, at the words of one of the officers that it was insulting to look at the French, Rostov began to shout with fervor, which was not justified in any way, and therefore greatly surprised the officers.
“And how can you judge which would be better!” he shouted, his face suddenly flushed with blood. - How can you judge the actions of the sovereign, what right do we have to reason ?! We cannot understand either the purpose or the actions of the sovereign!
“Yes, I didn’t say a word about the sovereign,” the officer justified himself, who could not explain his temper to himself except by the fact that Rostov was drunk.
But Rostov did not listen.
“We are not diplomatic officials, but we are soldiers and nothing else,” he continued. - They tell us to die - so die. And if they are punished, it means that they are to blame; not for us to judge. It is pleasing to the sovereign emperor to recognize Bonaparte as emperor and conclude an alliance with him - then it must be so. Otherwise, if we began to judge and reason about everything, nothing sacred would remain that way. So we say that there is no God, there is nothing, - Nikolai shouted, striking the table, very inappropriately, according to the concepts of his interlocutors, but very consistently in the course of his thoughts.
“Our business is to do our duty, to fight and not to think, that’s all,” he concluded.
“And drink,” said one of the officers, who did not want to quarrel.
“Yes, and drink,” Nikolai picked up. - Hey, you! Another bottle! he shouted.

In 1808, Emperor Alexander traveled to Erfurt for a new meeting with Emperor Napoleon, and in high Petersburg society they talked a lot about the greatness of this solemn meeting.
In 1809, the proximity of the two rulers of the world, as Napoleon and Alexander were called, reached such a point that when Napoleon declared war on Austria that year, the Russian corps went abroad to assist their former enemy Bonaparte against their former ally, the Austrian emperor; to the point that in high society they talked about the possibility of a marriage between Napoleon and one of the sisters of Emperor Alexander. But, in addition to external political considerations, at that time the attention of Russian society with particular vivacity was drawn to the internal transformations that were being carried out at that time in all parts of the state administration.
Meanwhile, life, the real life of people with their essential interests of health, illness, work, recreation, with their own interests of thought, science, poetry, music, love, friendship, hatred, passions, went on, as always, independently and without political closeness or enmity with Napoleon Bonaparte, and beyond all possible transformations.
Prince Andrei lived without a break for two years in the countryside. All those enterprises on estates that Pierre started and did not bring to any result, constantly moving from one thing to another, all these enterprises, without showing them to anyone and without noticeable labor, were carried out by Prince Andrei.
He had in the highest degree that practical tenacity that Pierre lacked, which, without scope and effort on his part, gave movement to the cause.
One of his estates of three hundred souls of peasants was listed as free cultivators (this was one of the first examples in Russia), in others corvée was replaced by dues. In Bogucharovo, a learned grandmother was issued to his account to help women in childbirth, and the priest taught the children of peasants and yards to read and write for a salary.
One half of the time Prince Andrei spent in the Bald Mountains with his father and son, who was still with the nannies; the other half of the time in the Bogucharovo monastery, as his father called his village. Despite the indifference he showed to Pierre to all the external events of the world, he diligently followed them, received many books, and to his surprise noticed when fresh people from Petersburg, from the very whirlpool of life, came to him or to his father, that these people, in the knowledge of everything that happens in the external and domestic politics, far behind him, sitting without a break in the village.
In addition to classes on estates, in addition to general studies in reading a wide variety of books, Prince Andrei was at that time engaged in a critical analysis of our last two unfortunate campaigns and drawing up a project to change our military regulations and decrees.
In the spring of 1809, Prince Andrei went to the Ryazan estates of his son, whom he was the guardian of.
Warmed by the spring sun, he sat in the carriage, looking at the first grass, the first leaves of the birch, and the first puffs of white spring clouds scattered across the bright blue of the sky. He did not think about anything, but looked cheerfully and senselessly around.
We passed the ferry on which he spoke with Pierre a year ago. We passed a dirty village, threshing floors, greenery, a descent, with the remaining snow near the bridge, an ascent along washed-out clay, a strip of stubble and a shrub that was greening in some places, and drove into a birch forest on both sides of the road. It was almost hot in the forest, the wind could not be heard. The birch tree, all covered with green sticky leaves, did not move, and from under last year's leaves, lifting them, the first grass and purple flowers crawled out green. Scattered in some places along the birch forest, small spruce trees with their coarse eternal greenery unpleasantly reminded of winter. The horses snorted as they rode into the woods and became more sweaty.

Acetic aldehyde (other names: acetaldehyde, methylformaldehyde, ethanal) - belonging to the class of aldehydes. This substance is important for humans, it is found in coffee, bread, ripe fruits and vegetables. Synthesized by plants. It occurs naturally and is produced in large quantities by man. Formula of acetaldehyde: CH3-CHO.

Physical Properties

1. Acetic aldehyde is a colorless liquid with a sharp unpleasant odor.
2. Highly soluble in ether, alcohol and water.
3. is 44.05 grams/mol.
4. Density is 0.7 grams/centimeter³.

Thermal Properties

1. The melting point is -123 degrees.
2. The boiling point is 20 degrees.
3. equals -39 degrees.
4. Auto-ignition temperature is 185 degrees.

Obtaining acetaldehyde

1. The main way to obtain this substance is (the so-called Wacker process). This is what the reaction looks like:
2CH2 = C2H4 (ethylene) + O2 (oxygen) = 2CH3CHO (methyl formaldehyde)

2. Acetaldehyde can also be obtained by hydration of acetylene in the presence of mercury salts (the so-called Kucherov reaction). This produces phenol, which then isomerizes to an aldehyde.

3. The following method was popular before the advent of the above process. It was carried out by oxidation or dehydrogenation on a silver or copper catalyst.

The use of acetaldehyde

What substances do you need acetaldehyde to obtain? Acetic acid, butadiene, aldehyde polymers and some other organic substances.
- Used as a precursor (substance that participates in the reaction leading to the creation of the target substance) to acetic acid. However, the substance under consideration was soon ceased to be used in this way. This was because acetic acid is easier and cheaper to produce from methalone using the Kativa and Monsanto processes.
- Methylformaldehyde is an important precursor to pentaerythrol, pyridine derivatives and crotonaldehyde.
- Obtaining resins as a result of the fact that urea and acetaldehyde have the ability to condense.
- Obtaining ethylidene diacetate, from which the monomer polyvinyl acetate (vinyl acetate) is subsequently produced.

Tobacco addiction and acetaldehyde

This substance is a significant part of tobacco smoke. A recent demonstration has shown that the synergistic association of acetic acid with nicotine increases addiction (especially in individuals under thirty).

Alzheimer's disease and acetaldehyde

Those people who do not have the genetic factor for converting methylformaldehyde to acetic acid have a high risk of predisposition to such a disease as (or Alzheimer's disease), which usually occurs in old age.

Alcohol and methylformaldehyde

Presumably, the substance we are considering is a human carcinogen, since today there is evidence of the carcinogenicity of acetaldehyde in various animal experiments. In addition, methylformaldehyde damages DNA, thereby causing the development of the muscular system disproportionate to body weight, which is associated with a violation of protein metabolism in the body. A study of 800 alcoholics was conducted, as a result of which scientists came to the conclusion that people exposed to acetaldehyde have a defect in the gene for one enzyme - alcohol dehydrogenase. For this reason, these patients are at greater risk of developing kidney and upper liver cancer.

Security

This substance is toxic. It is an air pollutant from smoking or from exhaust emissions in traffic jams.

Chemistry tests for school certification

Ending. See the beginning in No. 3/2006

* "Asterisk" means comments: what knowledge and skills are controlled, problem solving.

The tests offered in the 1st and 2nd semesters differ in the material covered in the school curriculum. We are considering assignments for the beginning of the school year. Here, students' knowledge of the previous year of study is checked. For example, in the 11th grade, most of the questions (10 out of 15) are devoted to organic chemistry. In the 2nd half of the year, the test tasks will include questions studied in the 1st half of the current year of study.

What do 11th grade students need to know when taking this test? These are the concepts of "functional group", "homologues", "isomers"; names and chemical formulas of ten linear alkanes: methane CH 4, ethane C 2 H 6, propane C 3 H 8, etc.; trivial names of oxygen- and nitrogen-containing organic compounds: acetaldehyde, formaldehyde, acetic acid, ethyl alcohol, phenol, methyl acetate, methylamine; chemical properties of substances; qualitative reactions, for example, phenol, alkenes, aldehydes, glycerol. Knowledge of the classification of inorganic compounds is tested, in particular oxides - acidic, basic and amphoteric; ability to use electronic formulas of atoms; types of chemical bonds and crystal lattices, types of chemical reactions, calculations according to the reaction equation.

11th grade

Option 1

1. Compounds, which include the functional group NH 2, belong to the class:

1) amines; 2) nitro compounds;

3) carboxylic acids; 4) aldehydes.

* Functional groups (defining properties of the entire class of substances) nitrogen- and oxygen-containing organic compounds: a) NH 2 - amines; b) NO 2 - nitro compounds;
in) UNOH - carboxylic acids; G) DREAM - aldehydes.

2. Ethane homologue is:

1) C 2 H 4; 2) C 2 H 6; 3) C 6 H 6; 4) C 3 H 8.

* Homologues - substances that are similar in structure, differing in one or more groups CH 2 . Similar means belonging to the same class of substances, such as alkanes. Moreover, homologues have the same chains: either linear or branched. First you need to name (ethane) write the chemical formula of the substance(C 2 H 6) . Then, adding(C 2 H 6 + CH 2 C 3 H 8), get an answer.

3. Propane interacts with:

1) bromine; 2) hydrogen chloride;

3) hydrogen; 4) sodium hydroxide (solution).

*To answer the question, you need to know about propane belonging to alkanes, as well as the properties of alkanes. Alkanes are characterized by free radical substitution reactions with halogens:

4. Ethanol does not interact with:

1) Cu; 2) Na; 3) HCl; 4) About 2.

*Knowledge of the chemical properties of alcohols is tested. The textbooks give the properties of the substances of the class under study (in this matter, the properties of alcohols). It is only necessary to answer which of the four proposed substances ethanol does not interact with. Ethanol reactions:

The following reaction can lead you astray:

However, it does not involve copper - a reducing agent, but copper (II) oxide - an oxidizing agent, albeit a weak one.

5. Ethyl acetate is formed by the interaction of acetic acid with:

1) acetaldehyde; 2) ethylene;

* Ethyl acetate - an ester - a product of the interaction of acetic acid with ethyl alcohol:

Attachment to acetic acid of other reagents, such as ethylene, does not occur, because acetic acid is weak.

6. Acetaldehyde interacts with:

1) ethane; 2) hydrogen;

3) carbon monoxide(IV); 4) toluene.

*Of the proposed substances, acetaldehyde reacts only with hydrogen:

7. Substance X in the reaction scheme

CH 3 COOH + CH 3 OH X + H 2 O:

1) ethyl acetate; 2) ethanol;

3) methyl acetate; 4) diethyl ether.

*It is necessary to use the reaction equation from the answer to task 5. The difference is in the alcohol used (instead of ethanol - methanol) and in the reaction product, here the answer is methyl acetate.

8. Methylamine interacts with:

1) methane; 2) oxygen;

*Methylamine is a gas (t kip = -42 ° C), it is produced in the form of a 40% aqueous solution. It evaporates from concentrated solutions, and if you bring a lighted match to the neck of the flask, the gas CH 3 NH 2 flashes:

4CH 3 NH 2 + 9O 2 4CO 2 + 10H 2 O + 2N 2.

9. Unsaturated hydrocarbons are distinguished from saturated hydrocarbons using:

1) H 2 SO 4 (conc.); 2) NaOH (solution);

3) Ag2O; 4) KMnO 4 (solution).

*Qualitative reactions in chemistry are associated with the evolution of gas, the formation of a precipitate, and a change in the color of the solution. Unsaturated hydrocarbons decolorize the pink solution of potassium permanganate (hydroxylation occurs at the double bond). In the presence of acid, a colorless solution is obtained, and in a neutral medium, a brown precipitate forms. MNO2:

10. The interaction of solutions of copper(II) chloride and sodium hydroxide refers to the reactions:

1) connections; 2) decomposition;

3) exchange; 4) substitutions.

* Equation for the reaction of copper(II) chloride and sodium hydroxide occurring in solution:

CuCl 2 + 2NaOH \u003d Cu (OH) 2 + 2NaCl.

11. What element has the lowest oxidation state in the NaHSO 4 compound?

1) Hydrogen; 2) sulfur;

3) oxygen; 4) sodium.

* The lowest oxidation state (conditional charge of an atom) in a compound NaHSO4- at the oxygen atom, it is -2. The atoms of sodium, hydrogen and sulfur in NaHSO4 positive (and therefore greater than -2) oxidation states.

12. chemical bond in fluorine and methane molecules:

*Bond between identical non-metal atoms(F–F) - covalent non-polar, and between atoms of different non-metals(S–N) - covalent polar.

13. Specify the main oxide:

1) SO3; 2) FeO; 3) Al 2 O 3; 4) ZnO.

* The condition is necessary, but not sufficient: the main oxide is metal oxide. Therefore, we exclude the oxide SO 3 . Among the three remaining substances Al2O3 And ZnO are amphoteric oxides, and FeO is the basic oxide.

14. Electronic formula of external energy level boron atom:

1) 2s 2 2p 1 ; 2) 3s 2 3p 1 ; 3) 3s 2 3p 3 ; 4) 3s 1 .

* Boron is an element of the 2nd period of D.I. Mendeleev’s table, therefore, answer options 2–4, where the 3rd energy level appears, disappear.

15. The amount of bromine Br 2 that can attach acetylene with a volume of 11.2 liters (n.o.) according to the reaction equation

C 2 H 2 + 2Br 2 C 2 H 2 Br 4,

1) 1 mol; 2) 2 mol; 3) 0.5 mol; 4) 0.25 mol.

*Calculate the amount of acetylene substance taken into the reaction:

(C 2 H 2) = V/V M = 11.2 / 22.4 = 0.5 mol.

The coefficients in front of the formulas of substances in the reaction equation show the amount of substances of the participants in the reaction in moles. Let's make a proportion:

1 mol C 2 H 2 attaches 2 mol Br2 ,

0.5 mol C 2 H 2 » » x mol Br2 .

Hence x = 1 mol.

Answers

1 – 1, 2 – 4, 3 – 1, 4 – 1, 5 – 3, 6 – 2, 7 – 3, 8 – 2, 9 – 4,
10 – 3, 11 – 3, 12 – 3, 13 – 2, 14 – 1, 15 – 1.

Option 2

1. A substance with the molecular formula C 6 H 6 belongs to the class:

1) alkanes; 2) arenes;

3) alkynes; 4) alkenes.

*General formulas for hydrocarbons of different classes: FROM n H2 n+2 – alkanes, FROM n H2 n – alkenes, FROM n H2 n–2 – alkynes, FROM n H2 n–6 – arenas. Substituting n = 6, we find that the index 6 for hydrogen satisfies the "arena" class of substances.

2. Isomers are:

1) ethylene and acetylene;

2) 2-methylpropane and 2-methylbutane;

3) 2-methylbutane and n-pentane;

4) n-pentane and n-butane.

*Among hydrocarbons, isomers are substances with the same number of carbon atoms, as well as hydrogen atoms. Molecular formulas of the proposed substances:

1) C 2 H 4 and C 2 H 2; 2) C 4 H 10 and C 5 H 12;

3) C 5 H 12 and C 5 H 12; 4) C 5 H 12 and C 4 H 10.

This shows that the correct answer is 3.

3. With the complete combustion of propane C 3 H 8, the following are formed:

1) C and H 2 O; 2) CO 2 and H 2 O;

3) CO and H 2; 4) CO and H 2 O.

*With the complete combustion of hydrocarbons, carbon dioxide and water (oxides of the elements that make up the original hydrocarbon) are formed.

4. The similarity of phenol and monohydric alcohols is manifested in interaction with:

1) NaOH (solution); 2) Na;

3) HCl; 4) HNO 3 (solution).

*Both phenol and alcohol react with sodium:

5. Butyl acetate is formed by the interaction of butanol with:

1) acetaldehyde; 2) acetic acid;

3) ethyl alcohol; 4) acetylene.

*Knowledge of the esterification reaction is checked, and at the same time, the nomenclature of esters (“butyl acetate”). Reaction equation:

6. Formaldehyde interacts with:

1) methane; 2) oxygen;

3) calcium hydroxide; 4) benzene.

* Some confusion in this issue is brought about by information about the first synthesis of sugary substances by the action of calcium hydroxide on formaldehyde (A.M. Butlerov, 1861):

The oxidation of formaldehyde with oxygen should be chosen:

7. Acetic acid can react with each substance of the pair:

1) methanol and silver;

2) copper(II) hydroxide and methanol;

3) silver and copper(II) hydroxide;

4) magnesium and methane.

*Three substances: methanol, silver and copper (II) hydroxide - are repeated in pairs in different combinations. It is necessary to recall a number of voltages of metals and the position of silver in it (to the right of hydrogen). Silver does not react with acetic acid, options 1 and 3 are excluded. Methane from answer 4 is also an inert substance with respect to CH 3 COOH. Choose answer 2:

2CH 3 COOH + Cu (OH) 2 (CH 3 COO) 2 Cu + 2H 2 O,

CH 3 COOH + CH 3 OH CH 3 COOSH 3 + H 2 O.

8. Ethylamine may react with:

1) KOH and HNO 3; 2) H 2 SO 4 and O 2;

3) NaOH and CH 3 OH; 4) NaCl and O 2 .

*Amines exhibit the properties of bases and react with acids. On the contrary, amines do not react with bases, so we exclude answer options 1 and 3. By the way, CH 3 OH also does not interact with ethylamine. Amines are burning(+ O 2) , but with salt NaCl do not react like any other organic matter. The correct choice is described by the reaction equations:

9. Glycerin in aqueous solution can be detected using:

1) bleach; 2) iron(III) chloride;

3) copper(II) hydroxide; 4) sodium hydroxide.

* Qualitative reaction to glycerol - the formation of bright blue copper (II) glycerate when interacting with copper (II) hydroxide:

10. The interaction of magnesium with hydrochloric acid refers to the reactions:

1) connections; 2) decomposition;

3) exchange; 4) substitutions.

*This is a substitution. Reaction equation:

Mg + 2HCl \u003d MgCl 2 + H 2.

11. A substance has an atomic crystal lattice:

1) water; 2) ozone; 3) graphite; 4) ammonia.

*Graphite has an atomic crystal lattice. The bond strength of many carbon atoms is equally high. In substances of molecular structure(H 2 O, O 3, NH 3) Bonds within a molecule are strong, but bonds between molecules are weak.

12. Chemical bond in water and hydrogen molecules:

1) covalent polar and covalent non-polar;

2) ionic and covalent polar;

3) covalent non-polar and covalent polar;

4) ionic and covalent non-polar.

* The task mentions substances with a covalent bond, as evidenced by the expression "in molecules". Water is a polar compound, hydrogen is non-polar.

13. Specify the acid oxide:

1) magnesium oxide; 2) zinc oxide;

3) Cr2O3; 4) CO 2 .

*Acid oxide - CO 2 . It corresponds to carbonic acid H 2 CO 3.

14. The electronic formula of the external energy level ( n) atoms of elements of group Vа (main subgroup):

1) ns 2 np 1 ; 2) ns 2 np 2 ; 3) ns 2 np 3 ; 4) ns 2 np 5 .

* The sum of the indices in the designations of the energy sublevels of the nth level for the elements of the Va group is equal to five. The only possible combination: ns 2 np 3 .

15. Mass of bromine interacting with 140 g of ethylene according to the reaction equation

C 2 H 4 + Br 2 C 2 H 4 Br 2,

1) 400 g; 2) 140 g; 3) 800 g; 4) 80

*Ethylene bromination reaction equation:

The required mass of bromine is denoted by x. The coefficients in front of the starting substances are the same, therefore(Br 2) \u003d (C 2 H 4) \u003d m/M = 140/28 = 5 mol. Accordingly, the mass of bromine:

m(Br 2) = M= 5 160 = 800 g.

Answers

1 – 2, 2 – 3, 3 – 2, 4 – 2, 5 – 2, 6 – 2, 7 – 2,
8 – 2, 9 – 3, 10 – 4, 11 – 3, 12 – 1, 13 – 4, 14 – 3, 15 – 3.

Acetic aldehyde belongs to organic compounds and belongs to the class of aldehydes. What properties does this substance have, and what does the formula of acetaldehyde look like?

general characteristics

Acetic aldehyde has several names: acetaldehyde, ethanal, methylformaldehyde. This compound is the aldehyde of acetic acid and ethanol. Its structural formula is as follows: CH 3 -CHO.

Rice. 1. Chemical formula of acetaldehyde.

A feature of this aldehyde is that it occurs both in nature and is produced artificially. In industry, the volume of production of this substance can be up to 1 million tons per year.

Ethanal is found in foods such as coffee, bread, and is also synthesized by plants during metabolism.

Acetic aldehyde is a colorless liquid with a pungent odor. Soluble in water, alcohol and ether. Is poisonous.

Rice. 2. Acetic aldehyde.

The liquid boils at a fairly low temperature - 20.2 degrees Celsius. Because of this, there are problems with its storage and transportation. Therefore, the substance is stored in the form of paraldehyde, and acetaldehyde is obtained from it, if necessary, by heating with sulfuric acid (or with any other mineral acid). Paraldehyde is a cyclic trimer of acetic acid.

How to get

Acetic aldehyde can be obtained in several ways. The most common option is the oxidation of ethylene or, as this method is also called, the Wacker process:

2CH 2 \u003d CH 2 + O 2 -2CH 3 CHO

The oxidizing agent in this reaction is palladium chloride.

Acetaldehyde can also be obtained by reacting acetylene with mercury salts. This reaction bears the name of a Russian scientist and is called the Kucherov reaction. As a result of the chemical process, enol is formed, which isomerizes to aldehyde

C 2 H 2 + H 2 O \u003d CH 3 CHO

Rice. 3. M. G. Kucherov portrait.

ACETALDEHYDE

- an intermediate product of the oxidation of ethyl alcohol (chemical formula C2H4O), containing an aldehyde group (H-C=O); in the body is formed with the participation of the enzyme alcohol dehydrogenase. Highly toxic, its de

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