af
^·*$$®* i i § ^ & *
Front view of the new pilot plant showing its position in the southeast section of the 100' acre property on which the Grasselli plant of General Aniline & Film Corp. is located
General Aniline & Film Unveils Acetylene Pilot Plant A STAFF REPORT A . N E W dimension in the synthesis of industrial organic chemicals i n trie United States was predicted with t h e formal unveiling on March 21, of General Aniline & Film Corp.'s new two-purpose pilot plant a t Grasselli, N . J. T h e m a i n part of the installation is devoted t o the exploration and extension of the famous high pressure acetylene reactions developed in Germany during the past decade by J. Walter Reppe of IG Farben.
Carl S. Marvel, University of Illinois, speaking at a luncheon formally opening the plant, said that this new plant m a y prove to be the basis in this country for a new reservoir of chemicals hitherto unavailable. One might well compare this advance, he thought, with the introduction of high pressure hydrogénation of nitrogen to give ammonia by t h e Haber process. T h e luncheon, at t h e Hotel Elizabeth
Heart of acetylene development—the compressor room. Compressor on right feeds gas to the vinylation and ethynylation towers. Hydrogen used in conversion of butynediol is compressed by pump at left, behind which stands A. Zoss and Hans Beller of the special products department at the Grasselli plant
976
CHEMICAL
Carteret in Elizabeth, N . J., was presided over b y Cary R. Wagner, vice president in charge of operations for General Aniline. Brief talks to the company's guests were given by Dr. Wagner; by Henry Hass, formerly with Purdue University and now director of GA research; and b y Hans Beller, manager of i t s special products department. The party w a s then conv e y e d in buses to Grasselli for inspection of the new plant. Dr. Marvel related how pressure synthesis had upped ammonia production from 4 5 million pounds in 1927 t o 2,180 million pounds in 1948, and that this had been attended by a drop in price from 8 cents per pound of nitrogen t o 4.5 cents. This experience in turn led t o the hydrogénation of CO and C 0 2 to furnish synthetic methanol of high purity, and again prices came down. Other pressure reactions became common in America suck a s Dow's conversion of chlorobenzene to aniline a n d phenol, the reduction of carbon monoxide to alcohols higher than methanol, the reduction of esters to alcohols over copper chromite, and the hydrogénation of aromatics to cyclohexane derivatives. T h e new acetylene chemistry is another of these novel contributions to industry, Marvel declared. Companies with less pioneering spirit than General Aniline & Film have been reluctant t o adopt high pressure acetylene chemistry, a n d the use of catalysts such a s t h e very sensitive copper acetylide. A significant feature of the GA pilot plant, h e observed, is t h e demonstration that the company is now indeAND
ENGINEERING
NEWS
pendent and that it does not have to rely on processes transmitted to it fully developed by a foreign laboratory. Dr. Beller said that the new high pressure technique at the acetylene pilot plant was actually simple and very practical if properly applied. Employing either nitrogen or propane as a diluting gas, acetylene synthesis has been carried out at over 200 p.s.L pressure, which heretofore has been considered very high for acetylene. A number of products obtained from acetylene were shown and explained by Dr. Beller at the plant. First Acetylene Plant in U. S. The construction of the plant marks the first time that facilities have been erected in the United States on a larger than laboratory scale to utilize reactions of acetylene under elevated pressures. In operation for only a little more than six months, it has already produced limited tank car and drum quantities of vinyl alkyl ethers, butynediol, butanediol, and many other compounds from acetylene. In an adjacent part of the same plant, units have also been installed for conducting pilot plant level investigations of new processes for the manufacture of dyes and
surface-active agents, two of the principal products of GA. Spokesmen for the company explained that the dual purpose design of the plant makes possible the convenient exchange of process units between this work and the acetylene operations, as needed. Acetylene, because of the extreme reactivity of its triple bond linkage, has long been regarded as potentially the most versatile building block for organic syntheses. Daring the last 30 years, low pressure processes currently using over 300 million pounds of acetylene annually havebeen developed in America for the manufacture of acetaldehyde, chlorinated solvents, vinyl acetate, vinyl chloride, chloroprene, and many other valuable compounds. In spite of the fact that high pressure reactions involving acetylene offered even greater possibilities, processes using them were avoided because of the explosiveness of acetylene under these conditions. Germany's lack of hydrocarbon raw materials, however, compelled her scientists to develop such processes. Prominent among these was the work of Reppe, who in the late thirties, managed to operate acetylene-based syntheses at temperatures
Virtylation tower in one of three-sided
concrete
stalls
The entire operation of the reaction towers is controlled from heavily re· inforced safety corridor which runs the full length of the five hays up to 200 e C. and 5 to 6 atmospheres of pressure, previously unheard of levels for that gas. The success of the IG Farben operations was due to the development of two new techniques for handling acetylene under pressure. Dilution of acetylene with an inert gas before compressing it was used to lower its reactivity. The other major precaution consisted of reducing to a minimum the volume of all spaces in the equipment where acetylene was confined. This latter feature entailed the use of bundles of small tubes instead of large conduits to convey the acetylene through the process and the packing of reactors with metal or porcelain rings to absorb thermal energies before an explosive state is reached by the reactants. Vinylation Vinylation, one of the two principal processes used in the Farben plant at Ludwigshafen, was employed by the Germans to form vinyl ethers for the manufacture of transparent and surgical tapes, dipped rubber products, adhesives for metals, lacquers, and sulfa drugs. Koresin, a valuable tackifier for synthetic rubber, was also made by this type of reaction. The other process, ethynylation was used to form 1,4-butynediol, which upon hydrogénation yields 1,4-butanediol, a glycol of great use and promise. United States patent rights to both of these processes are owned by General Aniline & Film Corp., which has made them the core of the operations in its new plant. According to strict convention, vinylation is the name given the process by which a vinyl group, CH2=CH—, is introduced into a molecule. Today, the term more specifically denotes the creation of a vinyl group by a reaction between acetylene and acids, alcohols, or like compounds. The equimolecular reactions of acetylene with hydrochloric and acetic
VOLUME
2 7, N O .
14»
» » » APRIL
4,
19 4 9
977
CATALYST ALCOHOI
VINYL ETHER STORAGE ;
PIMP: RECOVERED ALCOHOL
ACETYLENE COMPRESSOR
VIOLATION acids at moderate temperatures and low pressures are the basis of present day processes for the manufacture of vinyl chloride and vinyl acetate. The reaction to form vinyl ethers by the addition of one molecule of alcohol to one of acetylene can not be stopped at the "one for one" stage in the presence of the acid type catalysts normally used in vinylation. For this reason both the IG Farben and the new GA plants were de signed to employ an alkaline catalyst, which is dissolved in the alcohol to be viny lated. Since many of the latter boil at low temperatures, it is necessary to use pressure equipment and techniques for handling acetylene under pressures of 150200 p.s.i. The vinylation tower at the G A plant is 25 feet high, and about 1.5 feet in diameter and capable of withstanding a pressure of 100 atmospheres per square inch.
The vinylation reaction yields the vinyl alkyl ether, which after degasification of excess acetylene is ready for sale as a technical grade product. Rectification is conducted on a portion of this material to give a product of purer quality needed in certain applications. Εthy ny la tion Ethynylation, the process by which acetylene is condensed with such com pounds as formaldehyde, also uses acet ylene at high pressures and at high tem peratures as well. Post World War II investigators in Germany were startled to learn that Reppe had catalyzed his ethynylation reactions with copper acetylide, a substance even more explosive than acetylene itself. The principal ethynylation process, as used by GA consiste of mixing aqueous formaldehyde with undiluted acetylene
under a pressure of 90 p.s.i. and passing the mixture over a fixed bed of copper acetylide catalyst held at 100° C. The bed contains bismuth to inhibit the forma tion of undesirable cuprene. After tbe product is degassed and the unreacted formaldehyde and propargyl alcohol by product removed by distillation, the main product, butynediol, is isolated as a con centrated water solution. Subsequent hydrogénation of this material in the new G A plant results in- the formation of butanediol, which seems to have more immediate uses than its unsaturated parent. Although the GA plant closely follows the operations carried out by Reppe, new products have already been developed in the American enterprise to more than justify its undertaking. One of these, dimethyl chloroacetal, has shown itself to be a remarkable intermediate for organic
m&sm
RECOVERED FORMALDEHYDE
CCS
CO
es khi
es
OS
CO
FORMALDEHYDE
Ε*
BUTYNEDIOL STORAGE
immm fflsnr 978
ETHYNYUTION CHEMICAL
AND
ENGINEERING
NEWS
chemical syntheses b y being capable of reacting both a s an alkyl halide and an aldehyde. Another, malonaldehyde tetraalkydiacetal is a good source *of a dialdehydc and a s such is used in special types of condensation reactions. Butynediol, a crystalline acetylenic glycol of molecular weight 86.1 described b>' Reppe in his "Advances i n Acetylene Chemistry" (1940), and from which numerous chemicals can b e made, is one of the products now available for research purposes a s a result of G A development. Another, available in commercial quantities, is dimethyl chloroacetal, which forms peroxides when exposed to light. I t can react cither as an alkyl halide or an aldehyde, or both, depending upon the p H of the reaction. Polyvinyl methyl ether ( P V M ) also is being distributed in pilot plant quantities. P V M i s described as a polymer with the unique property o f solubility in cold water, b u t not in h o t water, and is said to merit study as a heat sensitizing agent for natural and synthetic latexes, a s tackifying agent for adhesives and cements, binding agent, and plasticizer. Another unique chemical resulting from the new acetylene technique is cyclooctatetraene, a product with four double bonds, which l e d a GA researcher to predict that its unexplored possibilities should provide a t least 50 years of investigation. Cyclooctatetraene i s derived from acetylene through the use of a nickel cyanide catalyst and pressures which give a 9 0 % yield. Because of t h e unpredictability of acetylene-based reactions, the design of the new GA plant incorporates m a n y other safety devices in addition t o those already
Rear view of pilot plant. At right are three large SO'foot fractionating used in isolating acetylene products. Another large still is at mentioned. T h e process reactions are carried out in large, three-sided concrete stalls, the open sides of which face out over nearby marshland. Remote control is effected from behind thick concrete walls, instrument leads and control mechanisms being led into the panel room through large disk-shaped steel barriers. Flame
High pressure hydrogénation is carried out in asbestos covered columns at left. Adjustments and readings are made from behind circular-shaped, steel-plated section
New
Text
Tanks provide alkynols9 and manufactured
stills left
arresting devices are liberally used in the heavy process equipment of the plant. The imminence of a dangerous situation in any part of t h e process is made known t o the operators b y an extensive system of alarm signals and counter-hazard devices are provided to alleviate such situations if an explosion threatens.
storage capacity for the vinyl ethers other products derived frown^ acetylene at the newly opened pilot plant
New Text
