1- acetic acid

Acetic Acid. Carbonylation of methanol is the most important reaction in the production of acetic acid.189-192 BASF developed a process applying C0I2 in the liquid phase under extreme reaction conditions (250°C, 650 atm).122 193 The Monsanto low-pressure process, in contrast, uses a more active catalyst combining a rhodium compound, a phosphine, and an iodine compound (in the form of HI, Mel, or T2).122 194—196 Methanol diluted with water to suppress the formation of methyl acetate is reacted under mild conditions (150-200°C, 33-65 atm) to produce acetic acid with 99% selectivity at 100% conversion. 

Dimethyl Carbonate. An industrial process to manufacture dimethyl carbonate through the oxidative carbonylation of methanol catalyzed by cuprous chloride has been developed and commercialized by EniChem.197,198 The reaction occurs in two steps. Cupric methoxy chloride is formed in the first oxidation step [Eq. (7.21)], which is then reduced to yield dimethyl carbonate and regenerate cuprous chloride [Eq. (7.22)]  

A continuous slurry process operated at moderate temperature and pressure (below 100°C, 10-20 atm) gives dimethyl carbonate with better than 98% selectivity. 

Acetic acid (CH3COOH) is one of the major components of bio-oils (up to 12 wt%). Furthermore, being non-flammable, it is a safe hydrogen carrier. Nevertheless, only a few studies have dealt with the production of hydrogen from acetic acid. 

The steam reforming of acetic acid is highly endothermic (Af-f 135kJmol at 25 °C) and it can be expressed by the following equation  

The network of reactions which may be take place during the process is fairly complex. Several reactions can occur simultaneously, such as thermal decomposition (Equations 6.24—6.26) and ketonization (Equation 6.27) of acetic acid  

Steam reforming of CH4 (Equation 6.28), methanation of CO (Equation 6.29) and CO2 (Equation 6.30), the Boudourd reaction (Equation 6.31) and the WGSR are also involved  

The complete steam reforming of acetic acid can be achieved over commercial Ni-based catalysts [79]. The operating temperature of these systems is aWays higher than 650 °C. The robustness of the catalysts based on Ni guarantees operation over thousands of hours, but this metal leads to extensive coke formation. In order to improve the stability, La203 vas introduced in the catalyst formulation [258]. 

Acetic acid has a very limited use in beverages, only finding use where its vinegary character can contribute to a suitable flavour balance in the intended product. It is seldom used in anything except non-fruit beverages. 

Pure glacial acetic acid is a colourless crystalline solid (m.p. 16°C) with a suffocating, pungent aroma. It is one of the strongest of the organic acids in terms of its dissociation constant and can displace carbonic acid from carbonates. 

Occurring widely in nature, malic acid is closely associated with apples. It is the second major acid, after citric, found in citrus fruits and it is present in most berry fruits. Malic acid is slightly stronger than citric in perceived acidity, imparting a fuller, smoother fruity flavour. 

Malic acid is a crystalline white solid (m.p. 100°C) and is highly soluble in water. Being less hygroscopic than citric acid it provides good storage and 

Malic acid finds use in a variety of products, mostly in fruit-flavoured carbonates. It is the preferred acidulant in low-calorie drinks and in cider and apple drinks, enhancing flavour and stabilising colour in carbonated and non-carbon-ated fruit-flavoured drinks. Malic acid may also be used to mask the off-taste of some sugar substitutes. Blends of malic and citric acids are said to exhibit better taste characteristics than either acidulant individually. 

Acetic acid (ethanoic acid, vinegar acid, CH3C02H, melting point 16.6°C, boiling point 117.9°C, density 1.0490, flash point 43°C, ignition temperature 465°C) is a colorless, pungent liquid that is miscible with water, alcohol, and ether in all proportions. 

Acetic acid is available commercially in several concentrations (1) glacial acetic is approximately 99.7% glacial acetic acid with water the principal impurity, (2) reagent grade acetic acid generally contains 36% acetic acid by weight, and (3) commercial aqueous solutions are usually 28,56, 70, 80, 85, and 90% acetic acid. 

Acetic acid is the active ingredient in vinegar, in which the content ranges from 4 to 5% acetic acid. Acetic acid is classified as a weak, monobasic acid (-C02H) but the three hydrogen atoms linked to the carbon atom (CH3) are not replaceable by metals. 

Acetic acid is manufactured by three processes acetaldehyde oxidation, //-butane oxidation, and methanol carbonylation.Ethylene is the exclusive organic raw material for making acetaldehyde, 70 percent of which is further oxidized to acetic acid or acetic anhydride. The single-stage (Wacker) process for making acetaldehyde involves cupric chloride and a small amount of palladium chloride in aqueous solution as a catalyst. 

The yield is 95 percent and further oxidation of the acetaldehyde produces acetic acid (Fig. 1). 

Acetic acid is also known as a solvent for nitrations. Unlike sulfuric acid this can advantageously be removed by distillation after the reaction is finished. 

Because of the expected better workup and disposal procedures, nitration in acetic acid was tried first. Stock solutions of4-(phenyl)morpholin-3-one in glacial acetic acid (2 m) and nitric acid (65%) in concentrated sulfuric acid (4.8 m) were used. For the reaction optimization, two disposable polypropylene syringes (3 mL capacity) were hlled with the different stock solutions and mounted on a syringe pump. The syringes were connected with the silicon micromixer that was connected with a residence time unit, a Teflon tube of known inner diameter and length. The flow of the syringe pump was adjusted according to the residence time required, the only variable. For simplicity, nitrations were carried out at room temperature. 

The whole system was allowed to reach equilibrium before 1 drop of efflux was collected in a HPLC autosampler-vial. This vial was charged with 2 mL of a 1 1 water-acetonitrile mixture to make sure the nitration is quenched immediately. 

The effectiveness of the quench was easily proven by recording a new HPLC chromatogram from the same vial 24 h after the first analysis the different chromatograms were superimposable. In acetic acid the nitration seems to be rather sluggish (Table 15.1). The starting material is consumed fairly slowly with a low yield of the desired meta/para mixture. From the increase of the imwanted ortho isomer over time one can state that the selectivity is rather low. To find out whether nitration at a higher temperature influenced the results, the experiment was repeated at 52 °C (Table 15.2). Now the reaction rate was increased, but the ratio of the ortho isomer versus the meta/para isomers was even worse. 

For the next experiment a 1 m solution of 4-(phenyl)morpholin-3-one in acetic acid was treated with neat fuming nitric acid. Then the nitrating species was used in roughly 24-fold molar excess. Now (Table 15.3) the reaction proceeds much faster. 

Acetic acid (uh-SEE-tik AS-id) is a clear, colorless liquid with a sharp odor. In its pure form, the compound is also known as glacial acetic acid. Acetic acid is the primary active ingredient of vinegar, which typically consists of about five parts of acetic acid mixed with 95 parts of water. The compound s name comes from the Latin word for vinegar, acetum. 

Acetic acid. Red atoms are oxygen black atoms are carbon and white atoms are hydrogen. The oxygen atom at top left shares a double bond with the nearby carbon atom. 

More than 1.4 million metric tons (1.5 million short tons) of acetic acid are produced in the United States annually. The largest fraction of that amount is used as a raw material in the manufacture of plastics. 

The most common method of making acetic acid is one developed by the Monsanto chemical corporation. In this process, synthesis gas (a mixture of carbon monoxide [CO] and hydrogen [H3]) is heated over a catalyst of copper metal mixed with zinc oxide to make methanol (methyl alcohol CH30H). The methanol is then treated with carbon monoxide (CO) to make acetic acid. Acetic acid can also be made by the fermentation of any material that contains sugar or some other carbohydrate. Although this method is of interest from a historical standpoint, it is not sufficiently efficient to use industrially. 

Ancient Romans boiled fermented wine (vinegar) in lead pots to make a sweet syrup called sapa. The acetic acid in the vinegar dissolved a small amount of lead from which the pots were made, producing lead acetate 

Acetic acid was originally produced by bacterial oxidation of ethanol, but from around 1914, synthetic acetic acid was produced by the oxidation of acetaldehyde. Hydrocarbon oxidation processes using butane or naphtha as feedstock were introduced in the 1950s. In a typical liquid phase oxidation process, a cobalt acetate catalyst operating at a temperature of 175°C, and a pressure of 54 bar was used, and by-products could be recycled. Conditions could be modified to produce methyl ethyl ketone. 

This process was rapidly rendered obsolete by the introduction of the low pressure process by Monsanto in 1971. The catalyst was similar to the Union Carbide hydroformylation catalyst, and was based on rhodinm caiboityl, promoted with iodine. The operating pressure was only aronnd 30-40 bar, with a 

While reaction rates for cobalt catalysts depend on the methanol concentration and partial pressure of carbon monoxide, the rates with rhodium catalysts are independent of both reactant and product concentrations. The reaction mechanism for cobalt catalyst in methanol carbonylation is similar to hydroformyla-tion but is different for rhodium catalysts. The catalyst intermediate in the rhodium process is Rh(CO)2l2 and has been identified at 100°C and 6 atm by infrared spectroscopy. Reaction with methyl iodide in the rate-determining step then forms a methyl rhodium complex that rapidly gives an acyl complex (CH3CORh(CO)l3)2 from reaction with the high carbon monoxide content in the reactor. The complex decomposes after reaction with water to produce acetic acid, and with simultaneous regeneration of the catalyst  

By 1999 more than two-thirds of worldwide acetic acid was made by the Monsanto process using the rhodium catalyst. BP Chemicals purchased the rights to the process in 1986 and in 1996 introduced a promoted iridium acetate catalyst that was claimed to be more efficient with easier purificatioa A comparison of the BASF and Monsanto processes is shown in Table 7.10. 

By-products Methane, acetaldehyde, ethanol, carbon dioxide Virtually none 

Commercial acetic acid is manufactured fiom pyroligneous acid obtained in the destructive distillation of wood. The latter is neutralised with lime, and separated by distillation from wood-spirit and acetone. The crude calcium acetate, which has a dark colour, is then distilled with the requisite quantity of concentrated hydrochloric acid. Anhydrous or glacial acetic acid is obtained by distilling fused sodium acetate with concentrated sulphuric acid. 

Properties.—Colourless liquid with pungent smell b. p. 119° m. p. 167° sp. gr. ro55 at 15°. It should not decolorise a solution of permanganate. The vapour of the boiling acid Is inflammable. 

Reactions.—Add a few drops of alcohol to the same quantity of apetic acid, and an equal volume of concentrated sulphuric acid. Warm gently and notice the fruity smell of ethyl acetate. Neutralise a few drops of acetic acid by adding e.xcess of ammonia and boiling until neutral. Let cool and add a drop of ferric chloride. The red colour of ferric acetate is produced On boiling, basic ferric acetate is precipitated. 

Heat a very small quantity of potassium acetate with an equal bulk of arsenious oxide. The disagreeable and poisonous vapour of cacodyl oxide is evolved. 

Much of the acetic acid production is captive, dedicated to production of vinyl acetate (monomer). 

There are six producers of acetic acid in the United States. They are Celanese, Eastman Chemical, Millennium Chemical, Sterling Chemicals, DuPont, and Primester. The United States has a total productive capacity of 8 billion pounds annually. 

Acetic acid is used to produce vinyl acetate monomer to make ethylene vinyl acetate (EVA) elastomer. 

About 40% of acetic acid produced is used to make vinyl acetate, of which only a small portion is used to make the EVA elastomer. Most of the vinyl acetate is used to make PVA, PVOH, and PVB, which are used by the adhesives industry as well as by the paper, coatings, and textile industries. One-third of all acetic acid is used to make acetic anhydride while one-fifth is used to make terephthalic acid and acetate esters. 

In the United States, the volume of acetic acid will probably only increase about annually. 

Originally, acetic acid was produced by fermentation this is still the major process for the production of vinegar. Modern production is by acetaldehyde oxidation, liquid phase hydrocarbon oxidation and preferentially by methanol carbonylation. The latter process is to be preferred because of the low raw material and energy costs. As early as 1913 BASF described the carbonylation of methanol at high temperature and pressure  

Due to the extreme conditions commercialization was not successful. Corrosion was very important only gold and graphite appeared to be resistant enough. Even gold-lined autoclaves were used. In the early 30s the process was abandoned for economic reasons. 

Carbonylation with homogeneous nickel catalysts was very extensively studied by Reppe in the thirties and forties. This work was not published until 1953. This process was commercialized in 1955. 

In 1941 Reppe demonstrated the potential of many metal carbonyls in several reactions including hydroformylation. This work resulted in 1960 in a process based on C0I2 operating at 700 bar and 250°C. Corrosion problems were overcome by applying Hastelloy C. 

In 1968 Monsanto reported a chemically related process based on rhodium iodide complexes. Due to its high reaction rates, high selectivity and different kinetics, the process differs substantially from the cobalt process. Commercialization was achieved in 1970. Operating conditions are remarkably mild 30 bar, 180°C. 

Corrosion by acetic acid can be aproblem in petrochemical process units. As a rule, even 0.1% water in acetic acid can have a significant influence on the corrosion rate. 

Temperature increases the corrosion rate, bromide and chloride contamination causes pitting and see, while the addition of oxidizing agents, including air, can reduce the corrosion rate. Type 304 stainless steel can be use for temperatures below 90 °e and Type 316 and 317 for hot acetic acid appheations. 

The mechanism by which acetic acid molecules combine to give double molecules has been the object of much speculation. Many cases of polymerization of organic substances are known but most of them lead to large units of indefinite molecular weights, such for example as are found in the polymerization of formalde- 

The manner in which these dimers break up into monomers offers an interesting problem in kinetics which can be studied by means of the infrared absorption spectrum. Acetic acid vapor at 19 mm. was examined13 from 1 jx to 10/x in an eight centimeter cell at 25° and at 172°. Several bands appear in this region and five fundamental frequencies were found corresponding to five fundamental modes of vibration. 

On heating to 172° where the dissociation into simple molecules is practically complete there is little change in the position of three of the bands but in two of the bands there is a definite shift. The band at 1,789 cm.-1 is known to be associated with the C = O group in aldehydes, ketones, esters, acids, and related compounds. As shown in Fig. 38 it undergoes a marked shift to smaller frequencies when it occurs in the dimers or double molecules. 

This large shift is certainly connected with the association or polymerization process. At 172° practically all the molecules exist as single molecules and at 25° they all exist as dimers. At intermediate temperatures where density measurements have proved that both forms exist in chemical equilibrium, there should be evidence of the existence of both bands. The doublet character of of the graphs for 64° and 82° shows that both these bands are present and confirms the basic assumptions. 

The formation of the dimer can be explained best on the basis of the formation of a monoplanar molecule with an eight-mem-bered ring. Two molecules of acetic acid may be represented as follows. 

DOT Label Corrosive Material, UN 2789 (glacial, more than 80% acid by weight) and UN 2789 (between 25 and 80% acid by weight) 

Synonyms glacial acetic acid ethanoic acid methanecarboxylic acid vinegar acid 

Acetic acid occurs in vinegar. It is produced in the destructive distillation of wood. It finds extensive application in the chemical industry. It is used in the manufacture of cellulose acetate, acetate rayon, and various acetate and acetyl compounds as a solvent for gums, oils, and resins as a food preservative in printing and dyeing and in organic synthesis. 

Colorless liquid with a pungent odor of vinegar boils at 118°C (244.4°F) sohdifies at 16.7°C (62.06°F) density of the liquid 1.049 at 25°C (77°F) miscible with water and most 

Glacial acetic acid is toxic to humans and animals by inhalation and skin contact. In humans, exposure to 1000 ppm for a few minutes may cause eye and respiratory tract irritation. Rabbits died from 4-hour exposure to a concentration of 16,000 ppm in air. 

LABORATORY CHEMICAL SAFETY SUMMARY ACETIC ACID  

Physical Properties Colorless liquid bp 118 °C, mp 17 °C Miscible in water (100 g/100 mL) 

Odor Strong, pungent, vinegar-like odor detectable at 0.2 to 1.0 ppm 

Major Hazards Corrosive to the skin and eyes vapor or mist is very irritating and can be destructive to the eyes, mucous membranes, and respiratory system ingestion causes internal irritation and severe injury. 

Toxicity The acute toxicity of acetic acid is low. The immediate toxic effects of acetic acid are due to its corrosive action and dehydration of tissues with which it comes in contact. A 10% aqueous solution of acetic acid produced mild or no irritation on guinea pig skin. At 25 to 50%, generally severe irritation results. In the eye, a 4 to 10% solution will produce immediate pain and sometimes injury to the cornea. Acetic acid solutions of 80% or greater concentration can cause serious bums of the skin and eyes. Acetic acid is slightly toxic by inhalation exposure to 50 ppm is extremely irritating to the eyes, nose, and throat. Acetic acid has not been found to be carcinogenic or to show reproductive or developmental toxicity in humans. 

3 An overview of individual organic acids and their applications 2.3.1 Acetic acid 

Theophrastos (272—287 Bc) studied the utilisation of acetic acid to make white lead and verdigris [52503-64-7]. Acetic acid was also weU-known to alchemists of the Renaissance. Andreas Libavius (ad 1540—1600) distinguished the properties of vinegar from those of icelike (glacial) acetic acid obtained by dry distillation of copper acetate or similar heavy metal acetates. Numerous attempts to prepare glacial acetic acid by distillation of vinegar proved to be in vain, however. 

Lavoisier beUeved he could distinguish acetic acid from acetous acid, the hypothetical acid of vinegar, which he thought was converted into acetic acid by oxidation. Following Lavoisier s demise, Adet proved the essential identity of acetic acid and acetous acid, the latter being the monohydrate, and in 1847, Kolbe finally prepared acetic acid from the elements. 

Most of the acetic acid is produced in the United States, Germany, Great Britain, Japan, France, Canada, and Mexico. Total annual production in these countries is close to four million tons. Uses include the manufacture of vinyl acetate [108-05-4] and acetic anhydride [108-24-7]. Vinyl acetate is used to make latex emulsion resins for paints, adhesives, paper coatings, and textile finishing agents. Acetic anhydride is used in making cellulose acetate fibers, cigarette filter tow, and ceUulosic plastics. 

Acetic acid, fp 16.635°C ((1), bp 117.87°C at 101.3 kPa (2), is a clear, colorless Hquid. Water is the chief impurity in acetic acid although other materials such as acetaldehyde, acetic anhydride, formic acid, biacetyl, methyl acetate, ethyl acetoacetate, iron, and mercury are also sometimes found. Water significantly lowers the freezing point of glacial acetic acid as do acetic anhydride and methyl acetate (3). The presence of acetaldehyde [75-07-0] or formic acid [64-18-6] is commonly revealed by permanganate tests biacetyl [431-03-8] and iron are indicated by color. Ethyl acetoacetate [141-97-9] may cause slight color in acetic acid and is often mistaken for formic acid because it reduces mercuric chloride to calomel. Traces of mercury provoke catastrophic corrosion of aluminum metal, often employed in shipping the acid. 

The vapor density of acetic acid suggests a molecular weight much higher than the formula weight, 60.06. Indeed, the acid normally exists as a dimer (4), both in the vapor phase (5) and in solution (6). This vapor density anomaly has important consequences in engineering computations, particularly in distillations. 

Acetic acid containing less than 1% water is called glacial. It is hygroscopic and the freezing point is a convenient way to determine purity (7). Water is neady always present in far greater quantities than any other impurity. Table 1 shows the freezing points for acetic acid-water mixtures. 

Selectivity is a major issue for the monochlorination of acetic acid to chloroacetic acid because second chlorination gives dichloroacetic acid and other chlorinated species including add chloride formation [314]. The removal of these impurities, especially of the dichloroacetic acid either by crystallization or by redudion with a palladium catalyst, is laborious and costly. 

Biosynthesis of Flavonoids (58) from 4-Hydroxycinnamic Acid (14) and Acetic Acid 

One mole 4-hydroxycinnamic acid (14) might react with 3 mol acetic acids to yield a precursor chalcone (57) and then flavonoids (58) (Fig. 11) [25,26]. The proposed biosynthesis of flavonoids was confirmed in a Antirrhinum majus 

The biosynthetic pathways of epicatechin (55), cyanidin (51) and proan-thocyanidin (PA) (44) had the same intermediates to leucocyanidin (48). Next, leucoanthocyanidin reductase (LAR) converts the leucocyanidin (48) to epicathechin (55), whereas leucoanthocyanidin dioxygenase (LDOX) converted leucocyanidin (48) to cyanidin (51). Two cyanidin (51) and epicathechin (55) are a precursor of proanthocyanidins (PA) (44). 

Camellia sinensis L. such as green tea leaves contains abundantly functional catechins such as (+)-catechin (43), (-)-epicatechin (62), (-)-epigallo-catechin (63) and (+)-gallocatechin (64). Interestingly, these flavan-3-ols might play a crucial role in the defense of the human body against various bacteria (Fig. 14). 

The anthocyanidin reductase enzyme recently described in Arabidopsis and Medicago was shown to be present in tea with very high activity and could produce epicatechin as well as epigallocatechin from the respective anthocyanidins, thus explaining very high contents of llavan-3-ols. Especially, two enzymes, dihydroflavonol 4-reductase and leucoanthocyanidin 4-reductase selectively catalyze key steps in their biosynthesis of catechins (43,62) and gallocatechins (63,64), respectively (Fig. 14) [31]. 

Oxodedihydro Bisubstitution - Catalyzed Oxidation of Ethanol with HjOj to Acetic Acid 

1 Drivers for Performing Catalyzed Oxidations with HjOj in Micro Reactors 

The catalyzed oxidation of ethanol to acetic acid is a well-studied reaction, carried out in continuous stirred tank reactors (CSTR) [51]. Hence it is a good test reaction for benchmarking micro reactor results. 

2 Beneficial Micro Reactor Properties for Cataiyzed Oxidations with HjOj 

Micro reaction channels can be operated in tight contact with cooling channels so that large reaction heats can be removed. By this means, formerly uncontrollable reaction conditions may be realized. 

Monsanto developed the rhodium-catalysed process for the carbonylation of methanol to produce acetic acid in the late sixties. It is a large-scale operation employing a rhodium/iodide catalyst converting methanol and carbon monoxide into acetic acid. At standard conditions the reaction is thermodynamically allowed, 

Other methods for the preparation of acetic acid are partial oxidation of butane, oxidation of ethanal -obtained from Wacker oxidation of ethene-, biooxidation of ethanol for food applications, and we may add the same carbonylation reaction carried out with a cobalt catalyst or an iridium catalyst. The rhodium and iridium catalysts have several distinct advantages over the cobalt catalyst they are much fester and fer more selective. In process terms the higher rate is translated into much lower pressures (the cobalt catalyst is operated by BASF at pressures of 700 bar). For years now the Monsanto process (now owned by BP) has been the most attractive route for the preparation of acetic acid, but in recent years the iridium-based CATTVA process, developed by BP, has come on stream. 

The two catalyst components are rhodium and iodide. Under the circumstances CO and water reduce Rhl3 to monovalent rhodium. A large 

The percentage of the selectivity in methanol is in the high nineties but the selectivity in carbon monoxide may be as low as 90%. This is due to the shift reaction  

The mechanism of the shift reaction in this catalyst system involves the attack of hydroxide anion at coordinated carbon monoxide, forming a metallacarboxylic acid. Elimination of C02 gives a rhodium hydride species that can react with the proton stemming from water to give dihydrogen. Rhodium may be either Rh(I) or Rh(III) as the valence of the metal does not change during this process. 

Biosynthetic routes often have product-specific advantages over chemical synthesis, which are important for extending and adding value to some bulk products listed in O Table 1.1. For example, optically active compounds, such as lactic acid, can be produced as either l- or o-lactic acid employing specific species of lactobacilli as biocatalysts, whereas chemical synthesis produces a racemic mixture of d, L-lactic acid. Specific properties of polylactide polymers and chemical derivatives of lactic acid differ importantly depending upon the chirality of the monomer (stereospecificity). 

Biodegradability of final products such as plastic bottles and films has become an important environmental concern. Where biodegradability is a desirable property, polyhydrox-yalkanoate- and polylactide-based plastics produced from bacterial processes are under development for replacement of poorly biodegradable polyvinyl, polyethylene, and other petroleum-based plastics. 

As the world population increases beyond the six-billion mark, urban, food processing, and agricultural wastes become 

Research into the bacterial production of 2,3-butanediol (see section 2,3 Butanediol Production in Chapter 2) also has been considerable. The future prospects of large-scale fermentative production of 2,3-butanediol as a fuel or as a major chemical feedstock will depend on the need to substitute for present petroleum-based products such as 1,3-butadiene and methyl ethyl ketone (Maddox 1996). 

In the following sections, we try not only to indicate the major bacterial systems developed for the production of the specific organic acids or solvents but also to give a realistic assessment of the relative impact of competing processes. 

Besides their importance as acylating agents and as reaction partners in ester condensations in carbon-14 syntheses, [ CJacetic acid and its derivatives are indispensible precursors for a broad spectrum of low molecular weight-labeled building blocks such as alkyl halo[ C] acetates, alkyl phosphono[ C]acetates, alkyl cyano[ C]acetates, dialkyl [ C]malonates, and alkyl [ CJacetoacetates. In addition to [ C]acetic acid, this section covers the primary derivatives their uses. 

CJacetyl chloride, [ C]acetic anhydride and esters of [ C]acetic acid and 

Preparation of Compounds Labeled with Tritium and Carbon-14 Rolf Voges, J. Richard Heys and Thomas Moenius 2009 John Wiley Sons, Ltd. ISBN 978-0-470-51607-2 

Both procedures can be modified so as to obtain acetic acid isotopomers labeled at the alternate positions i.e. CHgMgl (or CHgLi) and CO2 in Procedure A and and 

CH3I in Procedure The organometaUic component in the first case is accessible 

ACGIH has not established a threshold limit value for acetamide. 

Kennedy GL, Jr Biological effects on acetamide, formamide, and their monomethyl and dimethyl derivatives. CRC CritRev Toxicol 17 129-182, 1986 

lARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man, Vol 7, Some anti-thyroid and related substances, nitrofu-rans and industrial chemicals, pp 197-200. Lyon, International Agency for Research on Cancer, 1974 

Synonyms Ethanoic acid ethylic acid methane carboxylic acid vinegar (4-6% solution in water) 

Blaszkewicz and Neidhart [5] investigated the HPLC determination of inorganic lead and some organolead species of concern to occupational 

The authors next tested a 5-/im Nucleosil Cjs column, 200 mm x 4-mm i.d., using similar mobile phases, and all five lead species could 

In order to quantify the metal species, the authors sought to postcolumn react the lead species with 4-(2-pyridylazo)-resorcinol (PAR) in order to form intense red complexes, which could be detected using absorption monitoring. However, because only the diallqrllead compounds and Pb(II) were complexed by PAR, it was necessary to mix the effluent with a dilute solution of iodine prior to the addition of the PAR reagent. This was done to cleave the lead-carbon bonds of the tri- and 

Caruso and co-workers [7] separated alkyltin compounds using micellar liquid chromatography and tested the compatibility of this separation technique with inductively coupled plasma mass spectrometric detection (ICP-MS). This study was undertaken because many of the HPLC separations developed for these compounds involve the use of hydro-organic mobile phases, and use of organic solvents with ICP-MS results in a decrease in sensitivity due to excessive solvent loading of the plasma. Separations for many of these species were shown using 5-/im Ci8 Spherisorb silica-bonded columns, 50 mm x 4.6 mm i.d., and mobile phases containing sodium dodecyl sulfate, acetic acid, propanol, and potassium fluoride. 

The relative retention of Co(II) and Ni(II) was the same for each of the three columns. There were, however, indications that the mechanism of ion-exchange was different for each column. For instance, the relative positions of the Co(II) and Ni(II) curves for the Brownlee and Aminex columns using a citrate eluent (curves 1 and 3, Fig. 6.4) are reversed. Although the data for the Nucleosil column were not shown, the authors indicate that the HETP values were constant over the range of citrate concentrations studied. 

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Figure 3-5. Fugacity coefficients for the system acetaldehyde-acetic acid.

Two additional illustrations are given in Figures 6 and 7 which show fugacity coefficients for two binary systems along the vapor-liquid saturation curve at a total pressure of 1 atm. These results are based on the chemical theory of vapor-phase imperfection and on experimental vapor-liquid equilibrium data for the binary systems. In the system formic acid (1) - acetic acid (2), <() (for y = 1) is lower than formic acid at 100.5°C has a stronger tendency to dimerize than does acetic acid at 118.2°C. Since strong dimerization occurs between all three possible pairs, (fij and not... 

The largest errors in predicted compositions occur for the systems acetic acid-formic acid-water and acetone-acetonitrile-water where experimental uncertainties are significantly greater than those for other systems. 

Figure 5-3. Enthalpy concentration diagram for acetic acid-water at 1.013 bar.

Figure 3 presents results for acetic acid(1)-water(2) at 1 atm. In this case deviations from ideality are important for the vapor phase as well as the liquid phase. For the vapor phase, calculations are based on the chemical theory of vapor-phase imperfections, as discussed in Chapter 3. Calculated results are in good agreement with similar calculations reported by Lemlich et al. (1957). ... 

Homogeneous catalysts. With a homogeneous catalyst, the reaction proceeds entirely in the vapor or liquid phase. The catalyst may modify the reaction mechanism by participation in the reaction but is regenerated in a subsequent step. The catalyst is then free to promote further reaction. An example of such a homogeneous catalytic reaction is the production of acetic anhydride. In the first stage of the process, acetic acid is pyrolyzed to ketene in the gas phase at TOO C ... 

Figure 14.8a shows a simplified flowsheet for the manufacture of acetic anhydride as presented by Jeffries. Acetone feed is cracked in a furnace to ketene and the byproduct methane. The methane is used as furnace fuel. A second reactor forms acetic anhydride by the reaction between ketene from the first reaction and acetic acid. 

EDTA Efhylenediamineletra-acetic acid. EFA Essential fatty acids. ... 

CF3CO2H. Colourless liquid, b.p. 72-5 C, fumes in air. Trifluoroacetic acid is the most important halogen-substituted acetic acid. It is a very strong acid (pK = o y) and used extensively for acid catalysed reactions, especially ester cleavage in peptide synthesis. 

Calcium complex soap greases, obtained by the reaction of lime and a mixture of fatty acids and acetic acid. These greases offer good high temperature and anti-wear/extreme pressure properties related to the presence, in the soap, of calcium acetate that acts as solid lubricant they have good mechanical stability. 

A large variety of organic oxidations, reductions, and rearrangements show photocatalysis at interfaces, usually of a semiconductor. The subject has been reviewed [326,327] some specific examples are the photo-Kolbe reaction (decarboxylation of acetic acid) using Pt supported on anatase [328], the pho-... 

In a weak electrolyte (e.g. an aqueous solution of acetic acid) the solute molecules AB are incompletely dissociated into ions and according to the familiar chemical equation... 

Many of the inorganic oxoacids are strong (i.e. have negative PX3 values) in aqueous solution. But, as we have seen, use of a solvent with a lower proton affinity than water (for example pure ethanoic (acetic) acid makes it possible to differentiate between the strengths of these acids and measure pX values. The order of strength of some typical oxoacids is then found to be (for H X -> H , X- + H") ... 

The dissociation constant of ethanoic (acetic) acid in liquid ammonia is greater than it is in water. Suggest a reason for the difference. 

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