Oxidation, acetaldehyde ammonia

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. 

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... 

Nonporous silver membrane tube (99.99 wt.% Ag), (in double pipe configurationX thickness 100/im. Feed enters the reactor at shell side, oxygen at tube side. Oxidation of ammonia. Silver catalyst in membrane form (see previous column). Oxidation of ethanol to acetaldehyde. Silver catalyst in membrane form (see previous column). r- 250-380°C. The yield of nitrogen was 40%, the yield of nitrogen monoxide was 25%. r- 250-380°C. The yield of acetaldehyde was 83%. The yield with bulk powdered silver catalyst was 56%. Gryaznov, Vedernikov and Guryanova (1986)... 

Acid Amides can be produced by acylating ammonia with esters, acid anhydrides, or the acids themselves (above 100 °C) an important product is formamide from methyl formate. Alternatively acid amides can be synthesized by reacting acid halides with ammonia. Catalytic hydrogenation converts the acid amides to primary amines. Ammonia and aldehydes or ketones are the basis for different stable products. With formaldehyde hexamethylenetetramine (urotropine) is obtained with acetaldehyde, ammono acetaldehyde with benzaldehyde, hydrobenzamide with ethylene and propylene oxides, aqueous ammonia reacts to form ethanol- or propanolamine. 

Fixed-bed reactors consist of one or more tubes packed with catalyst particles and operated in a. vertical position. The catalyst particles may be a variety of sizes and shapes granular, pelleted, cylinders, spheres, etc. In some instances, particularly with metallic catalysts such as platinum, instead of using single particles, wires of the metal are made into screens. Multiple layers of these screens constitute the catalyst bed. Such screen or gauze catalysts are used in commercial processes for the oxidation of ammonia and the oxidation of acetaldehyde to acetic acid. 

ACIDE CYANHYDRIQUE (French) (74-90-8) Can be self-reactive, forming an explosive mixture with air (flash point 0°F/— 18°C). Unless inhibited, material stored more than 90 days may be hazardous. Heat above 356°F/180°C or contact with alkalis or amines can cause explosive polymerization. Violent reaction with strong oxidizers, acetaldehyde. Solutions containing more than 2—5% water are less stable than dry material. Acid solutions react with ammonia, ferric oxide, halogens, ozone. Attacks some plastics, rubber, and coatings. Water solutions attack carbon steels at room temperatures and stainless steels (especially if stabilized with sulfuric acid) above 176°F780°C. 

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. 

Reduction of ammoniacal silver nitrate. Place about 5 ml. of AgNOj solution in a thoroughly clean test-tube, and add 2-3 drops of dil. NaOH solution. Add dil. ammonia solution, drop by drop, until the precipitated silver oxide is almost redissolved, then add 2 - 3 drops of formaldehyde or acetaldehyde. A silver mirror is formed. 

Ammonia, anhydrous Mercury, halogens, hypochlorites, chlorites, chlorine(I) oxide, hydrofluoric acid (anhydrous), hydrogen peroxide, chromium(VI) oxide, nitrogen dioxide, chromyl(VI) chloride, sulflnyl chloride, magnesium perchlorate, peroxodisul-fates, phosphorus pentoxide, acetaldehyde, ethylene oxide, acrolein, gold(III) chloride... 

Iodine Acetaldehyde, acetylene, aluminum, ammonia (aqueous or anhydrous), antimony, bromine pentafluoride, carbides, cesium oxide, chlorine, ethanol, fluorine, formamide, lithium, magnesium, phosphorus, pyridine, silver azide, sulfur trioxide... 

Chevron Chemical Co. began commercial production of isophthahc acid in 1956. The sulfur-based oxidation of / -xylene in aqueous ammonia at about 320°C and 7,000—14,000 kPa produced the amide. This amide was then hydrolyzed with sulfuric acid to produce isophthahc acid at about 98% purity. Arco Chemical Co. began production in 1970 using air oxidation in acetic acid catalyzed by a cobalt salt and promoted by acetaldehyde at 100—150°C and 1400—2800 kPa (14—28 atm). The cmde isophthahc acid was dissolved and recrystallized to yield a product exceeding 99% purity. The Arco technology was not competitive and the plant was shut down in 1974. 

Oxidation catalysts are either metals that chemisorb oxygen readily, such as platinum or silver, or transition metal oxides that are able to give and take oxygen by reason of their having several possible oxidation states. Ethylene oxide is formed with silver, ammonia is oxidized with platinum, and silver or copper in the form of metal screens catalyze the oxidation of methanol to formaldehyde. Cobalt catalysis is used in the following oxidations butane to acetic acid and to butyl-hydroperoxide, cyclohexane to cyclohexylperoxide, acetaldehyde to acetic acid and toluene to benzoic acid. PdCh-CuCb is used for many liquid-phase oxidations and V9O5 combinations for many vapor-phase oxidations. 

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