Acetaldehyde, ammonia reaction

Reactions with Ammonia and Amines. Acetaldehyde readily adds ammonia to form acetaldehyde—ammonia. Diethyl amine [109-87-7] is obtained when acetaldehyde is added to a saturated aqueous or alcohoHc solution of ammonia and the mixture is heated to 50—75°C in the presence of a nickel catalyst and hydrogen at 1.2 MPa (12 atm). Pyridine [110-86-1] and pyridine derivatives are made from paraldehyde and aqueous ammonia in the presence of a catalyst at elevated temperatures (62) acetaldehyde may also be used but the yields of pyridine are generally lower than when paraldehyde is the starting material. The vapor-phase reaction of formaldehyde, acetaldehyde, and ammonia at 360°C over oxide catalyst was studied a 49% yield of pyridine and picolines was obtained using an activated siHca—alumina catalyst (63). Brown polymers result when acetaldehyde reacts with ammonia or amines at a pH of 6—7 and temperature of 3—25°C (64). Primary amines and acetaldehyde condense to give Schiff bases CH2CH=NR. The Schiff base reverts to the starting materials in the presence of acids. 

Acetaldehyde can be isolated and identified by the characteristic melting points of the crystalline compounds formed with hydrazines, semicarbazides, etc these derivatives of aldehydes can be separated by paper and column chromatography (104,113). Acetaldehyde has been separated quantitatively from other carbonyl compounds on an ion-exchange resin in the bisulfite form the aldehyde is then eluted from the column with a solution of sodium chloride (114). In larger quantities, acetaldehyde may be isolated by passing the vapor into ether, then saturating with dry ammonia acetaldehyde—ammonia crystallizes from the solution. Reactions with bisulfite, hydrazines, oximes, semicarb azides, and 5,5-dimethyl-1,3-cyclohexanedione [126-81 -8] (dimedone) have also been used to isolate acetaldehyde from various solutions. 

Variations on this theme include the use of acrolein/ammonia (72GEP2224160) and acrolein/acetaldehyde/ammonia (64BRP963887,69BRP1141526). Ketones can also be utilized. For example, 2,6-dimethylpyridine is obtained in 36% yield from combination of for-malin/acetone/ammonia (71GEP2064397) (Scheme 3). This general reaction has recently been extended to include the preparation of 2,6-disubstituted (78BEP858390) and 2,3-disubstituted (78GEP2712694) pyridines from aromatic or heteroaromatic ketones/aliphatic aldehydes and ammonia. 

It is reported that the compd is formed by the reaction of acetaldehyde-ammonia ammonia (Ref 1). This reaction yielded a max of 87% gum from which the separation of not more than 3% of Hexaethylidenetetramine was possible. Nitration attempt of the product was not considered practicable. The above reaction is analogous to the hexamethylenetetramine from which RDX is prepd by... 

The reaction between aldehydes and ammonia leads to compounds usually called aldehyde ammonias (equation 80). The first reported compound ( acetaldehyde ammonia ) was synthesized by Liebig (1835LA(14)133). Nielsen et al. (73JOC3288) have shown that most of these compounds are hexahydro-l,3,5-triazines, which are usually isolated as the trihydrates (Table 17). When aldehydes containing a branched alkyl substituent are used, the free hexahydro-l,3,5-triazines may be formed (Table 17). The kinetics of the reaction between acetaldehyde and ammonia have been studied by H NMR spectroscopy (73JOC2931), and shown to be rather complex. It is beyond the scope of this review to discuss the reaction fully. 

Strecker, A. The preparation of a new material by the reaction of acetaldehyde-ammonia imine and hydrogen cyanide. Liebigs Ann. Chem. 

METHACETALDEHYDE (108-62-3) Forms explosive mixture with air (flash point 97°F/36°C). Contact with heat, steam, hot surfaces forms acetaldehyde. Violent reaction with strong oxidizers, bromine, ketones. Incompatible with strong acids, caustics, ammonia, amines. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

Particularly when PVP is considered for application as a blood plasma extender, trace amounts of extraneous materials may be objectionable. The ammonia-hydrogen peroxide system discussed above may give rise to acetaldehyde-ammonia complexes that may be capable of further condensation reactions. Hydrogen peroxide may also oxidize acetaldehyde to acetic acid. The molecular weight distribution of the polymer also appears to be critical in blood plasma extenders. 

In 1850, A. Strecker accidently accomplished the first synthesis of the amino acid alanine by mixing of acetaldehyde, ammonia, and HCN and subsequent hydrolysis of the formed adduct [1]. Whereby this three-component-reaction is in general known as the Strecker reaction, the addition of a cyanide source to a preformed imine species is often referred to as the modified Strecker reaction, The so-formed a-amino nitriles, or from cyanide addition to carbonyl compounds the so-obtained cyanohydrins, are versatile building blocks that can be converted, for example, into a-hydroxy carbon acids, amino acids, amino alcohols and diamines. 

This reaction consists of the condensation of two molecular equivalents of a 1,3 diketone (or a J3-keto-ester) with one equivalent of an aldehyde and one of ammonia. Thus the interaction of ethyl acetoacetate and acetaldehyde and ammonia affords the 1,4-dihy dro-pyridine derivative (1), which when boiled with dilute nitric acid readily undergoes dehydrogenation and aromatisation" to gb e the diethyl ester of collidine (or 2,4,6-trimethyl-pyridine-3,5 dicarboxylic acid (II)). For the initial condensation the solid aldehyde-ammonia can conveniently be used in place of the separate reagents. 

Reaction of formaldehyde, methanol, acetaldehyde, and ammonia over a siUca alumina catalyst at 500°C gives pyridine [110-86-1] and 3-picoline... 

Acrolein and ammonia give P-picoline (3, R — H) (eq. 17). Acrolein, ammonia, and acetaldehyde give pyridine (1) (eq. 19). Acrolein, ammonia, and propionaldehyde give (3) (eq. 20) (52—56). Reactions are performed in the vapor phase with proprietary catalysts. 

Fig. 1. Four-bond reactions formaldehyde, acetaldehyde, and ammonia mainly give pyridine (1), and acetaldehyde and ammonia give a- (2) and y-picoline...

A radical reaction is sometimes observed to compete with the particularly slow acid hydrolyses of diaziridines derived from formaldehyde. With other diaziridines the radical reaction can be made to predominate by using HCl in carbon tetrachloride solution. Acetaldehyde, butyraldehyde, butylamine and ammonia are obtained from (160) (64CB49). 

Most diaziridines are not sensitive towards alkali. As an exception, diaziridines derived from 2-hydroxyketones are quickly decomposed by heating with aqueous alkali. Acetaldehyde, acetic acid and ammonia are formed from (162). This reaction is not a simple N—N cleavage effected intramolecularly by a deprotonated hydroxy group, since highly purified hydroxydiaziridine (162) is quite stable towards alkali. Addition of small amounts of hydroxybutanone results in fast decomposition. An assumed reaction path — Grob fragmentation of a hydroxyketone-diaziridine adduct (163) — is in accord with these observations (B-67MI50800). 

When 2,7-dimethyloxepin is treated with potassium in liquid ammonia at — 70 C, a mixture of oct-4-en-2-one (1) and octa-4,6-dien-2-one (2) in a ratio of 75 20 is obtained.203 The major product can be separated by preparative gas chromatography in 23% yield. The analogous reaction of 3-benzoxepin gives, in 30% yield, a mixture of (2-cthylphenyl)acetaldehyde (3) and (2-ethynylphenyl)acetaldehyde (4) that resists separation.203 The Latter product can be formed exclusively in 17% yield when 3-benzoxepin is treated with sodium amide in tetra-hydrofuran at 33 C for 210 minutes.203... 

Taurine is generally prepared from ox bile1 or the large muscle of the abalone.2 It has been synthesized from isethionic add through chloroethanesulfonic acid followed by the action of aqueous ammonia 3 from ethyleneimine and sulfur dioxide 4 from 2-mercaptothiazoline by oxidation with bromine water 5 from bromoethylamine and ammonium sulfite 6 and from acetaldehyde by a complex set of reactions involving sulfonation, formation of the aldehyde ammonia and the imido sulfonic add and finally reduction.7 The method given in the procedure has recently appeared in the literature.8 9... 

Alternatively, hydrogen sulfide could be produced alongside ammonia and acetaldehyde by the breakdown of the mercaptoimino-enol intermediate of the decarboxylation reaction of the cysteine-dicarbonyl condensation product. Fisher also points out that hydrogen sulfide is forms many odiferous an hence intensely flavoured products.2 Cysteine is important as it is one of the major sources of sulfur. 

Halogens, See also Bromine (Br) Chlorine (Cl) Fluorine (F) Iodine (I) higher aliphatic alcohols, 2 5 in N-halamines, 13 98 reactions with acetaldehyde, 1 105 reactions with acetone, 1 163 reactions with acetylene, 1 180 reactions with alkanolamines from olefin oxides and ammonia, 2 125—126 reactions with aluminum, 2 284—285, 349-359... 

In from eight to ten hours up to 10 1. of acetylene are taken up. The colourless intermediate mercury compound very soon begins to separate. After the passing in of acetylene has ceased the whole of the reaction mixture is transferred to a round-bottomed flask and heated on a conical (Babo) air bath, while steam is passed through to decompose the mercury compound. The acetaldehyde liberated distils with the steam. An apparatus similar to that described under (a) is used one receiver containing ether and cooled in a freezing mixture is sufficient. The aldehyde is precipitated from the ethereal solution as aldehyde-ammonia in the manner described above. Yield of aldehyde-ammonia 5-6 g. 

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