TECHNOLOGY
New Hydrazine Route Competes with Raschig West German process, based on forming an intermediate, may alter economics of producing hydrazine A hydrazine process developed in West Germany may become a potent competitor to the more familiar Raschig process. The Free World's producers of hydrazine now use the Raschig process or variations of it to make the reactive compound. But Bergbau-Forschung (in Essen) has developed a hydrazine process, based on the formation of a ketone intermediate, which could alter the economics of producing hydrazine. At least one major hydrazine producer, Britain's Whiff en & Sons, Ltd., a wholly owned subsidiary of Fisons, has obtained a license from BergbauForschung. The Free World's sales of hydrazine are only about $20 million—a scale which keeps it in the specialty
class. Hydrazine is well established in herbicides, pharmaceuticals, freeradical catalysts, plant growth inhibitors, oxygen scavengers, and blowing agents. Growth prospects for the versatile building-block chemical for existing uses are good (10 to 15% a year world-wide, about 20% in the U.S.). Expensive. It costs about 95 cents a pound in the U.S. for bulk shipments of 100% hydrate and about 80 cents a pound on the same basis in western Europe. Small price reductions in the past have had little effect, indicating that demand for the material is inelastic and that before new, largevolume uses appear, current prices must be trimmed 20% or more. New technology that makes such
reductions possible is the goal of a number of investigators. Alternatives to the Raschig process range from those in the research stage to the Bergbau-Forschung and Bayer processes in West Germany, which are poised for commercialization. Starting materials for the Raschig process are chlorine and ammonia. Chlorine reacts with caustic soda to produce sodium hypochlorite. Hypochlorite and ammonia at 30 atm. and at about 130° C. proceed through monochloramine to form hydrazine, sodium chloride, and water. Yields (on a chlorine basis) are about 60%. Hydrazine concentrations must be kept at 1 to 2 % to prevent a side reaction of hydrazine with monochloramine to give ammonium chloride
A Dozen Producers in the Free World Make Hydrazine Country
Producer
Location
West Germany
Farbenfabriken Bayer, A.G.
Leverkusen
7
France
Monople des Poudres Société des Produits d'Azotes
Toulouse Lannemezan
1
Whiffen & Sons, Ltd.
Loughborough Widnes
3 3
Great Britain Japan
For captive use
Hikari Chemical Industries Co., Ltd. Japan Hydrazine Co., Inc. Otsuka Chemical Co.
Ohmiya City
1.5
Tokyo
1.5*
Osaka
4*
Spain
Quimica Sintetica
Madrid
0.2
United States
Olin Mathieson
Lake Charles, La. Saltville, Va.
Fairmount Chemical National Polychemicals Naugatuck Chemical Total * C&EN estimate.
38
Capacity, 100% Hydrazine Hydrate> (million lb. Remarks per year)
C&EN JULY
5, 1965
Newark, N. J.
3 24
Olin-operated plant for U.S. Government produces anhydrous hydrazine
1
For captive use
Wilmington, Mass. Geismar, La.
Under construction
3 52.2
and nitrogen. This dilution increases the cost of the Raschig process, since heat is needed for subsequent removal of large amounts of water. There are also chances for yield loss through hydrazine leakage. The laboratory developments stress fissiochemical or electric-arc techniques. Aerojet-General, for example, is using enriched uranium oxide particles to irradiate ammonia molecules. This forms ions and free radicals that recombine to give hydrogen, nitrogen, and hydrazine. The newer processes are variations of the Raschig process. In the Bergbau-Forschung version, ammonia and chlorine react in the presence of a ketone (butanone and the various pentanones are the most suitable) to give diazacyclopropane. This compound is an intermediate that is then used to make hydrazine derivatives. Bergbau-Forschung, a subsidiary which conducts research for Steinkohlenbergbauverein—an association of all the coal companies in West Germany—stakes its process hopes on low power requirements and high yields. A 7% concentration of the diazacyclopropane intermediate (in ketone) produced by this reaction can be ob-
tained easily. The intermediate is converted without isolation to hydrazine hydrate, monosulfate, another hydrazine derivative, or a salt. Ammonium chloride is a by-product. Farbenfabriken Bayer, A.G., in West Germany also has a new process based on ammonia and chlorine. The firm won't reveal details but says that its process is ready for commercial-scale operations. The process uses acetone. Urea. Hydrazine can also be made from urea, sodium hypochlorite, and caustic soda, but this process has given way to the lower-cost ammonia route. Fairmount Chemical, at its Newark, N.J., plant, switched from urea to the basic ammonia route when it expanded to about 1 million lb.-per-year capacity in 1963. A commercial hydrazine process should be able to make both the hydrate and sulfate of hydrazine. Bergbau makes the hydrate by a stoichiometric reaction of diazacyclopropane with the ketone in the presence of an acid catalyst to form a ketazine. The ketazine can be hydrolyzed under pressure to hydrazine hydrate. Bayer has also explored this route to the hydrate. Extractive distillation
of the hydrate produces anhydrous hydrazine. The ketazine can also be used as starting material for the production of special blowing agents, according to Bergbau. A reaction of diazacyclopropane with sulfuric acid produces hydrazine sulfate. In both the sulfate and hydrate steps, the ketone is recovered and can be recycled. Bergbau-Forschung cites these advantages for its process: •Over-all yield (on a chlorine basis) of 90%. • L o w e r capital investment, compared with Raschig plants. • L o w e r steam requirements because of the low heat of vaporization of ketone, compared with water, and the high concentrations of diazacyclopropane in ketone that are possible. Ketone consumption now amounts to 0.32 lb. of butanone or 0.1 lb. of pentanone per pound of hydrazine. However, the firm says, further development of its process could reduce ketone consumption. There are now 12 hydrazine producers in the Free World. Producers in western Europe believe hydrazine is made in Eastern bloc countries. But
Ketone recycle Sulfuric acid
Versatility is Feature of Bergbau Process
Ketone
Ammonia
> Diazacyclopropane
Hydrazine sulfate Water
Acid catalyst
Ketazine Ketone to recycle Ammonium chloride by-product
- • Hydrazine hydrate JULY
5, 1965
C&EN
39
they are not certain, since isonicotinic hydrazide (a drug for treating tuberculosis) is still imported in large quantities by the East. The drug is usually one of the first hydrazine products made captively. Military uses for hydrazine outweigh its commercial markets in the U.S. Olin Mathieson built and operates a 15 million lb.-per-year anhydrous hydrazine plant at Saltville, Va., for the U.S. Government's rocket program. The fuel for Titan II is a mixture of nitrogen tetroxide oxidizer and a blend of equal parts of hydrazine and UDMH (unsymmetrical dimethylhydrazine). UDMH can be made by the Raschig process. Generally, though, it's made from dimethylamine and sodium nitrite, which form dimethylnitrosamine. Reduction of this compound with metals such as nickel
gives UDMH. FMC at Baltimore is the only U.S. producer of UDMH. Strong growth prospects for hydrazine lie in the production of blowing agents for making plastic foams, herbicides, and pharmaceuticals. An area where U.S. producers lag behind those in Europe is in opening the rapidly growing field of boiler treatment. In the U.S., higher selling price has held the use of hydrazine in boilerwater treatment to large power plants. A modern power plant producing 10 million lb. per hour of steam might require 50,000 lb. per year of hydrazine hydrate for oxygen scavenging (the reaction products of hydrazine and oxygen are water and nitrogen). With electrical power generation in the world doubling every 10 years the outlook for hydrazine in boiler-water treatment is bright.
Free World Production of Hydrazine Is Adequate
LARGEST. Olin's plant at Saltville, Va., is the largest producer of hydrazine, making anhydrous product for the U.S. Government
All hydrazine producers in the Free World make some hydrazine for civilian uses. Although the number of producers is small, there is no Free World shortage of hydrazine. The U.S. hydrazine producers are Olin Mathieson, National Polychemicals, Naugatuck (chemical division of U.S. Rubber), and Fairmount Chemical. In addition to its Saltville, Va., plant, Olin has a 3 million lb.-per-year plant at Lake Charles, La.; Fairmount has a 1 million lb.per-year plant at Newark, N.J.; and Naugatuck has a 3 million lb.-peryear plant at Geismar, La. National Polychemicals (Wilmington, Mass.), a wholly owned subsidiary of 40
C&EN
JULY
5,
1965
Fisons, produces hydrazine for captive use. France has two hydrazine producers: Société des Produits d'Azotes, which operates a small plant to satisfy its captive needs, and Monopie des Poudres, the government explosives producer. Hydrazine first became important in Germany during World War II as a rocket fuel. Farbenfabriken Bayer is the only producer. In England, the only producer is Whiffen & Sons, Ltd., a wholly owned subsidiary of Fisons. Fisons has a plant at Loughborough near Leicester, built in 1947; it's based on the Raschig process. The firm is building a second plant at Widnes, near Liverpool, which will double U.K. hydrazine capacity. Fisons has licensed the Bergbau-Forschung process on a nonexclusive basis. The only other hydrazine producer in western Europe is Quimica Sintetica, in Spain. A Parke-Davis subsidiary, it now operates a small plant with a 200,000 lb.-per-year capacity. In Japan, Japan Hydrazine Co., Otsuka Chemical Co., and Hikari Chemical Industries, Ltd., produce hydrazine and its derivatives. Western Europe's production of hydrazine for nonmilitary uses was about S million lb. in 1964 (on the basis of 1 0 0 % hydrate). U.S. production was about 5 million lb. Japan's production in 1964 was about 6.5 million lb., with about twice as much sulfate as hydrate.
Electrostatic Separator Handles Nonconductors Uses electrostatic field to deflect feed into separate streams An old theoretical concept and some new design features have been combined by H. Leslie Bullock in developing a new series of electrostatic separators introduced by National Engineering Co. The new equipment separates mixtures of dry solids and it represents the Chicago company's first venture into separation methods. Mr. Bullock holds several patents on electrostatic separation and he recently joined National Engineering as a technical director. The old concept is that of statically charging the solid feed by agitating it. The new design features include insulating the inside of the equipment. This enables the charge to be built up and used to deflect different materials in the feed into separate streams while the feed falls through an electrostatic field between two non conductive surfaces. According to Mr. Bullock, this approach gives equipment that is cheaper, more versatile, and of greater capacity than previous separators. Most earlier machines use an electrodynamic field established between two metal surfaces. Known as Bullock-Simpson electrostatic separators, the new machines have many potential uses, according to National Engineering. They can separate mixtures of conductors, of nonconductors, and of both. Most earlier machines cannot separate mixtures of nonconductors. Applications for the new equipment include upgrading many metallic and nonmetallic ores, separating plastic scrap, and even removing sand and other foreign matter from tobacco. To date, National Engineering has concentrated on solids blending equipment, such as the Simpson Mix-Muller. The new field the company is entering is not crowded—Carpco Research & Engineering, Inc., of Jacksonville, Fla., claims to be the only domestic maker of commercial high-tension and electrostatic separators for mixtures of solids. Dielectric. The Bullock-Simpson separator works on the principle that two substances which have different dielectric constants will develop equal and opposite charges when they are
