Condensation of acetic acid

Vapor-Phase Condensations of Acetic Acid or Esters with Formaldehyde. Addition of a methylol group to the a-carbon of acetic acid or esters, foUowed by dehydration, gives the acrylates. 

Most of the terephthalic acid is produced with a catalyst system developed by Scientific Design. It was purchased by Amoco and Mitsui and is referred to as the Amoco Oxidation. The solvent is acetic acid. Compressed air is used as the source for oxygen. The catalyst dissolved in acetic acid and the two reactants are continuously fed into the reactor. The temperature is around 200 °C and the pressure is approximately 25 bar. The reaction is very exothermic (1280 klrnoT1, calculation from data in Stull et al [16] often a much higher, erroneous value is cited). This heat of reaction is removed by evaporation/condensation of acetic acid and can be used in the solvent distillation/purification part of the plant. A scrubber washes the vent gases... 

Vinyl acetate was produced by the catalytic acetylation of acetylene, but this monomer is now produced by the catalytic oxidative condensation of acetic acid and ethylene (structure 17.32). Other vinyl esters can be produced by the transesterification of vinyl acetate with higher boiling carboxylic acids. 

Synthesis Feprazone is prepared by the condensation of acetic acid 3-methyl-but-2-enyl ester with the lithium salt of 1,2-diphenyl-pyrazolidine-3,5-dione in the presence of tetrakis(triphenylphosphin)palladium in anhydrous tetra-hydrofuran. 

The condensation of a carboxylic acid with ammonia or an amine yields an amide. The amide in Table 15-1 resulted from the condensation of propanoic acid with ammonia. The example in the preceding section involved the condensation of acetic acid with a primary amine. A very important class of biochemical molecules are the amino acids, which join to form protein molecules by the condensation of the amine group of one molecule to the acid group of the next. The amide linkage in this case has the special name peptide. 

The Model for 2-acetoxy-3-pentanone. This compound is formed by a condensation of acetic acid and 2-hydroxy-3-pentanone, common carbohydrate fragmentation products. As such it would be expected that C(r) would be important (from the carbohydrate source) and pH since its precursors are affected by both acid and base. The most significant model terms according to Prob > T were C(r) (0.0002)... 

They have an even number of carbon atoms because they are made in living things by Claisen ester style condensations of acetic acid derivatives. In fact, at some stage in the biosynthesis of palmitic acid, there was a carbonyl group at each atom marked with a green blob here. 

From thermodynamic calculations it is obvious that while all the reactions discussed above are thermodynamically possible, certain reactions are more probable. For example, thermodynamic calculations suggest that the condensation of acetic acid/CCald is more likely to proceed to CO2 as a byproduct, and this is in fact what was observed. When looked for, more CO2 is found than CO in the products of aldehyde/aldehyde condensations. It is also important to note that the Keq values for the acid/aldehyde and aldehyde/aldehyde formation of the ketone are both typically larger than for the acid/acid reaction. From this one might expect the turnover rate for ketone production to be larger for these two feeds. However, this is not what is observed. Again, this indicates some involvement of an adsorbed carboxylate, which cannot be formed directly from an aldehyde. 

The reaction that uses most of the acetyl-CoA formed by pyruvic acid is the condensation of acetic acid and the keto form of oxaloacetic acid to yield citric acid by forming a carbon-to-carbon bond between the methyl carbon of acetyl-CoA and the carbonyl carbon of oxaloacetate. This reaction is interesting in more than one respect. In addition to the fact that the reaction introduces the oxidation product of fatty acids, carbohydrates, and proteins into the tricarboxylic cycle by converting the 4-carbon chain of oxaloacetic acid into a 6-carbon chain (citric acid), the condensing enzyme presents a fascinating stereospecificity. 

V-P binary oxide consisting of vanadyl pyrophosphate, (V0)2P207i is a unique catalyst possessing an excellent selectivity in oxidation of butene and n-bu-tane to maleic anhydride. Further, this oxide is known to be effective also as a catalyst for a vapor-phase aldol condensation of acetic acid and propionic acid with formaldehyde (HCHO) to form acrylic acid and methacrylic acid, respec tively [1-3]. 

For purification, transfer the acid to a 150 ml. flask containing 60 ml. of water, boil the mixture under reflux, and then add acetic acid in 5 ml. portions down the condenser until almost all the solid has dissolved avoid an excess of acetic acid by ensuring that the solvent action of each addition is complete before the next portion is added. A small suspension of insoluble impurity may remain. Add 2 g. of animal charcoal, boil the solution again for 10-15 minutes, and then filter it through a preheated Buchner funnel. Cool and stir the filtrate, which will deposit pale cream-coloured crystals of the acid. Collect as before and if necessary repeat the recrystallisation. Yield of pure acid, 9 g. m.p. 227-229°. 

Acetonylacetone is available commercially as a by-product of the manufacture of acetic acid from acetylene. It may be prepared by condensation of chloroacetone with ethyl sodioacetoacetate the resulting ethyl acetonylacetoacetate when heated with water under pressure at 160° undergoes ketonic scission to give acetonylacetone. 

In a 1 litre round-bottomed flask, equipped with an air condenser, place a mixture of 44 g. of o-chlorobenzoic acid (Section IV,157) (1), 156 g. (153 ml.) of redistilled aniline, 41 g. of anhydrous potassium carbonate and 1 g. of cupric oxide. Reflux the mixture in an oil bath for 2 hours. Allow to cool. Remove the excess of aniline by steam distillation and add 20 g. of decolourising carbon to the brown residual solution. Boil the mixture for 15 minutes, and filter at the pump. Add the filtrate with stirring to a mixture of 30 ml. of concentrated hydrochloric acid and 60 ml. of water, and allow to cool. Filter off the precipitated acid with suction, and dry to constant weight upon filter paper in the air. The yield of iV-phenylanthranilic acid, m.p. 181-182° (capillary tube placed in preheated bath at 170°), is 50 g. This acid is pure enough for most purposes. It may be recrystaUised as follows dissolve 5 g. of the acid in either 25 ml. of alcohol or in 10 ml. of acetic acid, and add 5 ml. of hot water m.p. 182-183°. 

Alternatively, TiCl reacts with a cold mixture of acetic acid and acetic anhydride. If the mixture is heated, condensation occurs with elimination of acetyl chloride to yield hexaacetoxydititanoxane [4861 -18-1] (126,127). 

Other Rea.ctlons, The anhydride of neopentanoic acid, neopentanoyl anhydride [1538-75-6] can be made by the reaction of neopentanoic acid with acetic anhydride (25). The reaction of neopentanoic acid with acetone using various catalysts, such as titanium dioxide (26) or 2irconium oxide (27), gives 3,3-dimethyl-2-butanone [75-97-8] commonly referred to as pinacolone. Other routes to pinacolone include the reaction of pivaloyl chloride [3282-30-2] with Grignard reagents (28) and the condensation of neopentanoic acid with acetic acid using a rare-earth oxide catalyst (29). Amides of neopentanoic acid can be prepared direcdy from the acid, from the acid chloride, or from esters, using primary or secondary amines. 

Ferrocene (46.4 g., 0.250 mole) (Note 1) is added to a well-stirred solution of 43.2 g. (0.422 mole) of bis(dimethylamino)-methane (Note 2) and 43.2 g. of phosphoric acid in 400 ml. of acetic acid in a 2-1. three-necked round-bottomed flask equipped with a condenser, a nitrogen inlet, and a mechanical stirrer (Note 3). The resulting suspension is heated on a steam bath under a slow stream of nitrogen (Note 4) for 5 hours (Note 5). The reaction mixture, a dark-amber solution, is allowed to cool to room temperature and is diluted with 550 ml. of water. The unreacted ferrocene is removed by extracting the solution with three 325-ml. jiortions of ether. The aqueous solution is then looled in ice water and made alkaline by the addition of 245 g. 

A WBL can also be formed within the silicone phase but near the surface and caused by insufficiently crosslinked adhesive. This may result from an interference of the cure chemistry by species on the surface of substrate. An example where incompatibility between the substrate and the cure system can exist is the moisture cure condensation system. Acetic acid is released during the cure, and for substrates like concrete, the acid may form water-soluble salts at the interface. These salts create a weak boundary layer that will induce failure on exposure to rain. The CDT of polyolefins illustrates the direct effect of surface pretreatment and subsequent formation of a WBL by degradation of the polymer surface [72,73]. 

Comforth has reviewed literature reports and independently studied the special cases of reaction of 1 with salicylaldehyde and with 2-acetoxybenzaldehyde. Coumarins (10) are afforded in the condensation of 1 with salicylaldehyde or its imine, whereas when 2-acetoxybenzaldehyde is used, acetoxy oxazolone 12 is the major product. The initial aldol condensation product between the oxazolone and 2-acetoxybenzaldehyde is the 4-(a-hydroxybenzyl)oxazolone 11, in which base-catalyzed intramolecular transacetylation is envisioned. The product 9 (R = Ac) can either be acetylated on the phenolic hydroxy group, before or after loss of acetic acid, to yield the oxazolone 12, or it can rearrange, by a second intramolecular process catalyzed by base and acid, to the hydrocoumarin, which loses acetic acid to yield 10. When salicylaldehyde is the starting material, aldol intermediate 9 (R = H) can rearrange directly to a hydrocoumarin. Comforth also accessed pure 4-(2 -hydroxyphenylmethylene)-2-phenyloxazol-5(4//)-one (13) through hydrolysis of 12 with 88% sulfuric acid. 

Aliphatic and aromatic aldehydes condensed with 2-amino-(62BRP898414), 5-amino- (80AJC1147), or 8-amino-l,2,4-triazolo[l,5-cjpyrimidines (68JOC530) to give the related Schiff bases. Treatment of the 2-amino-5-methyl-l,2,4-triazolo[l,5-c]quinazoline 11 with formaldehyde and piperidine in the presence of acetic acid gave the 2-hydroxymethyl-amino-5-(2-piperidinoethyl) derivative 172. Utilization of aromatic aldehydes and piperidine in this reaction gave the 2-arylideneamino-5-styryl derivatives 173 (68CB2106) (Scheme 67). 

The cyclized analog of meralluride is prepared by a similar synthesis. Thus, condensation of camphoric acid (42) (obtained by oxidation of camphor) with ammonia gives the bicyclic succinimide (44). Reaction with allyl isocyanate followed by ring opening and then reaction with mercuric acetate affords the mercury derivative (45) as the acetate rather than the hydroxide as above. Reaction with sodium chloride converts that acetate to the halide (46). Displacement on mercury with the disodium salt of thioglycollic acid affords the diuretic mercaptomerine (47). ... 

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