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Vitamin A intermediate, pseudoionone, will begin coming from acetone when new Hoffmann-La Roche plant goes on stream in May at Nutley, N. J.
Acetone + Acetylene —* Vitamins N e w p l a n t uses t o t a l synthesis for vitamins A E, will also m a k e o t h e r i n t e r m e d i a t e s Building u p an organic mol ecule from C 2 ACS NATIONAL MEETING to C 40 and b e yond usually Organic starts and stops Chemistry in a lab. But not always. Next month, t h e first commercial plant for total syn thesis of terpenoids and sesquiterpenoids goes on stream in Nutley, N. J. There, Hoffmann-La Roche will make pseudoionone—the key intermediate for making vitamins A and Ε and /2-carotene—from acetone and acetylene. Also, the multi-million dollar plant will turn out chemicals used in the flavor and toilet-goods industries. Until now, vitamins A and Ε and βcarotene were m a d e by partial syn thesis based on citral which is extracted from lemon grass oil. But with the totally synthetic method, dependence on nature is removed, Walter Kimel of Hoffmann-La Roche told the Division of Organic Chemistry. The new manufacturing process, says Kimel, starts with reaction of ace tone and acetylene in liquid ammonia. The reaction gives methylbutynol. Partial hydrogénation of the acetylenic alcohol yields dimethylvinylcarbinol. 74
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In this step, Lindlar catalyst is used (palladium on calcium carbonate poisoned with lead). The catalyst permits a selective hydrogénation. Treating dimethylvinylcarbinol with diketene followed by pyrolysis forms methylheptenone. The reaction cycle is then repeated, this time starting with methylheptenone. The ketone is condensed with acetylene just as acetone was earlier, and diketene and pyrolysis are again used to complete pseudoionone synthesis. Product is isolated by distillation, with a yield of about 35% based on acetone and acetylene. In the older partial synthetic method, citral is extracted from lemon grass oil and condensed with acetone to make pseudoionone. From this point, the steps in vitamin manufacture are die same for both the naturally and synthetically made intermediate. Pseudoionone is converted directly to vitamin E, or to β-ionone. From the latter, vitamin A and β-carotene are made. ^ Multi-purpose Plant. HoffmannLa Roche's new plant has a lot of flexibility built into it. As director of technical development, Alfred Ofner puts it, "the plant was designed to fit the process." And the process can be
changed slightly to give a long series of flavor and perfume chemicals. Among tiiese are linalool, linalyl esters, citral, nerol, nerolidol, the ionones, irone, and many new compounds not now available. Some of the new chemicals, says Ofner, "should chal lenge the imagination of perfumers for the creation of novelties." According to Kimel, demand will determine which chemical will be made at any given time. Except for acetone, the new plant will be integrated into raw materials. The company makes its own diketene from acetone right at the plant site and also has its own acetylene genera tors. • " F r i n g e " Benefit. Aside from be ing a way of freeing an important vitamin series from uncertain natural sources, the process has another possi bility. Now that isoprene units can be built up to any length, substituted isoprenes can be made when needed or desired. For example, Joseph D. Surmatis (who, togedier with Kimel and other coworkers, worked out a good deal of the process) says that a series of carotene homologs have been made. These new carotenoids are substituted at different positions in the ionone ring when compared with regu lar carotene. T h e new compounds show considerable biological activity, he savs.
Coal Hydrogénation Bureau of Mines opens new approach to high B.t.u. gas; could be important if natural gas prices continue up High B.t.u. gas from coal is now a step ACS Ν Λ Τ Ϊ Ο Ν Α Ι MEETING closer to reality. industrial & The Bureau of Mines has de Engineering veloped a new Chemistry ^ bench scale hy drogénation unit which directly converts up to 9 0 % of subbituminous coal into gaseous hydrocarbons—mostly methane—in just 15 minutes. Significant, too, is the high aromatic content in the liquid endproducts—58% benzene. In the past, ways to high B.t.u. gas involved making synthesis gas (carbon monoxide and hydrogen), then converting to methane. Hence the new process opens a new approach to longrange plans to convert solid fuel to gaseous products. This is important now, because natural gas prices are rising and may become prohibitive for many uses within 10 years.
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