Fine pharmaceutical

The difference between well-known SCF antisolvent techniques such as GAS, PCA, and SEDS usually can be attributed to the specific nozzle mixing (or dispersing) technique involved. Enhanced mass and heat transfer can also be achieved by using mechanical and ultrasonic mixers and ultrafast jet expansion techniques. There are new developments for particle formation by means of dispersed systems such as emulsions, micelles, colloids, and polymer matrixes. It should be emphasized that all these processes involve the same fundamental aspects of mass and heat transfer phenomena between an SCF and a subcritical phase. Clearly the ultimate goal of all SCF particle technologies is to achieve predictable, consistent, and economical production of fine pharmaceuticals or chemicals. This is possible only on the basis of comprehensive mechanistic understanding and well-developed scale-up principles. 

Sievers RE, Huang ETS, Villa JA, Kawamoto JK, Evans MM, BrauerPure PR. Low-temperature manufacturing of fine pharmaceutical powders with supercritical fluid aero-solization in a bubble dryer. Appl Chem 2001 73(8) 1299 1303. 

Uses. Furan is utilised as a chemical building block in the production of other industrial chemicals for use as pharmaceuticals, herbicides, stabili2ers, and fine chemicals. There are a great many references to the use of furan as an intermediate in these applications. For a recent review, see Reference 104. Several of the principal uses are described below. 

From the point of view of appHcation, pharmaceutical fine chemicals constitute the largest part of all fine chemicals, both in terms of number of products and volume of sales. About 40—50% of the total fine chemicals sales comes from pharmaceutical fine chemicals about 20 to 25% are agrochemicals, and the rest belong to other categories. 

Not many fine chemicals have a production value exceeding 10 million per year. Less than a do2en achieve production volumes above 10,000 metric tons per year and sales of > 100 million per year. Apart from the pharmaceutical and pesticide fine chemicals these comprise the amino acids (qv), L-lysine and n,T-methionine used as feed additives (see Feeds AND FEED ADDITIVES), and vitamins ascorbic acid and nicotinic acid. 

Fine chemicals are generally considered chemicals that are manufactured to high and weU-defined standards of purity, as opposed to heavy chemicals made in large amounts to technical levels of purity. Fine chemicals usually are thought of as being produced on a small scale and the production of some fine chemicals is in tens or hundreds of kilograms per year. The production of others, especially fine chemicals used as dmgs or food additives (qv), is, however, in thousands of metric tons (see Pharmaceuticals). For example, the 1990 U.S. production of aspirin [50-78-2] and acetaminophen [103-90-2] was on the order of 20,500 t and 15,000 t, respectively. 

Uses. The principal uses of NaBH are ia synthesis of pharmaceuticals (qv) and fine organic chemicals removal of trace impurities from bulk organic chemicals wood-pulp bleaching, clay leaching, and vat-dye reductions and removal and recovery of trace metals from plant effluents. 

Ethynylation. Base-catalyzed addition of acetylene to carbonyl compounds to form -yn-ols and -yn-glycols (see Acetylene-DERIVED chemicals) is a general and versatile reaction for the production of many commercially useful products. Finely divided KOH can be used in organic solvents or Hquid ammonia. The latter system is widely used for the production of pharmaceuticals and perfumes. The primary commercial appHcation of ethynylation is in the production of 2-butyne-l,4-diol from acetylene and formaldehyde using supported copper acetyHde as catalyst in an aqueous Hquid-fiHed system. 

The second most important use of ketene is in the production of diketene [674-82-8] (3) by controUed dimeri2ation. Diketene has wide utility in the manufacture of pharmaceutical and agricultural chemicals, dyes, pigments and fine chemicals. 

ROOC—COOH, are not. The dialkyl esters are characterized by good solvent properties and serve as starting materials in the synthesis of many organic compounds, such as pharmaceuticals, agrochemicals, and fine chemicals (qv). Among the diesters, dimethyl, diethyl, and di- -butyl oxalates are industrially important. Their physical properties are given in Table 7. 

Oxalyl Chloride. This diacid chloride [79-37-8], ClCOCOCl, mol wt 126.9, is produced by the reaction of anhydrous oxaUc acid and phosphoms pentachloride. The compound vigorously reacts with water, alcohols, and amines, and is employed for the synthesis of agrochemicals, pharmaceuticals, and fine chemicals. 

Thiophene [110-02-1] and a number of its derivatives are significant in fine chemical industries as intermediates to many products for pharmaceutical, agrochemical, dyestuffs, and electronic appHcations. This article concentrates on the industrial, commercial, and economic aspects of the production and apphcations of thiophene and thiophene derivatives and details the main synthetic schemes to the parent ring system and simple alkyl and aryl derivatives. Functionalization of the ring and the synthesis of some functional derivatives that result, not from the parent ring system, but by direct ring cyclization reactions are also considered. Many good reviews on the chemistry of thiophene and thiophene derivatives are available (1 7). 

Benzaldehyde. Annual production of ben2aldehyde requires ca 6,500—10,000 t (2-3 x 10 gal) of toluene. It is produced mainly as by-product during oxidation of toluene to benzoic acid, but some is produced by hydrolysis of ben2al chloride. The main use of ben2aldehyde is as a chemical intermediate for production of fine chemicals used for food flavoring, pharmaceuticals, herbicides, and dyestuffs. 

Commercially, neopentanoyl chloride is often the preferred starting material for the synthesis of peroxyesters, agricultural chemicals, pharmaceuticals, esters, and other fine chemicals because the reactivity of the acid haUde is generally greater than that of the acid. 

---