Suitability for the Product

This aspect has first priority. Evaporators for sensible products, such as food and pharmaceutical products are an example for this. Microbe growth has to be avoided as much as possible. 

Vacuum Technology in the Chemical Industry, First Edition. Edited by Wolfgang Jorisch. 

The plants require a sanitary design, that is there must be no centre of infection, the product must not form residuals in the plant, the plant has to be rinsed well in all points. 

In order to reduce the microbe growth, the residence time of the product in the plant should be defined, a back-mixing for example, is very detrimental. This can be ensured by a single pass of the product. 

Short residence times and small filling volumes are requested for the same reason. 

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Resin and Polymer Solvent. Dimethylacetamide is an exceUent solvent for synthetic and natural resins. It readily dissolves vinyl polymers, acrylates, ceUulose derivatives, styrene polymers, and linear polyesters. Because of its high polarity, DMAC has been found particularly useful as a solvent for polyacrylonitrile, its copolymers, and interpolymers. Copolymers containing at least 85% acrylonitrile dissolve ia DMAC to form solutions suitable for the production of films and yams (9). DMAC is reportedly an exceUent solvent for the copolymers of acrylonitrile and vinyl formate (10), vinylpyridine (11), or aUyl glycidyl ether (12). 

High process temperatures generally not achievable by other means are possible when induction heating of a graphite susceptor is combined with the use of low conductivity high temperature insulation such as flake carbon interposed between the coil and the susceptor. Temperatures of 3000°C are routine for both batch or continuous production. Processes include purification, graphitization, chemical vapor deposition, or carbon vapor deposition to produce components for the aircraft and defense industry. Figure 7 illustrates a furnace suitable for the production of aerospace brake components in a batch operation. 

Electric Power Generation. Hydrothermal steam and hot water resources having temperatures ia excess of about 150°C are generaHy suitable for the production of electricity (see Eig. 3a). Because electricity is easy to market and transport, it is the only product of hydrothermal energy which permits the resource to be utilized at some distance from its actual location. 

There are, however, continuing difficulties for catalytic appHcations of ion implantation. One is possible corrosion of the substrate of the implanted or sputtered active layer this is the main factor in the long-term stabiHty of the catalyst. Ion implanted metals may be buried below the surface layer of the substrate and hence show no activity. Preparation of catalysts with high surface areas present problems for ion beam techniques. Although it is apparent that ion implantation is not suitable for the production of catalysts in a porous form, the results indicate its strong potential for the production and study of catalytic surfaces that caimot be fabricated by more conventional methods. 

Copper [7440-50-8] Cu, critically important to the development of civilization, is the only common metal found naturally in the metallic state. It was thus suitable for the production of tools, and ancient people made use of its easy workabiUty and beauty. Furthermore, the ease with which the oxide can be reduced to the metal, together with the tendency of copper to alloy with other metals naturally present in the ores, promoted broad usage. 

During the next few years PVC was steadily developed in the United States and in Germany. Both countries were producing the material commercially before World War II. In Great Britain, ICI in 1942 and the Distillers Company in 1943 also commenced pilot-plant production of PVC, a material then in demand as a rubber substitute for cable insulation. Paste-forming grades suitable for the production of leathercloth also became available soon afterwards. 

The ED process is a reliable, membrane-based, electrically driven demineralization technology that is more than 50 years old. It is suitable for the production of basic pure water from lower TDS supply sources. Commercial ED units consist of hundreds of individual cells in a modular membrane sandwich arrangement, bounded by electrodes and linked to a direct current (DC) rectifier-controller. The total treated water flow is a function of the number of cells in the ED unit. 

A description is given of a comparative study of the glycolysis of PETP waste soft drinks bottles by various mixtures of EG and DEG with subsequent polyesterification of the glycolysed products by maleic anhydride in order to obtain unsaturated polyesters suitable for the production of varnishes. The processing characteristics such as viscosity, exotherm temperatures of curing, compatibility of resins with monomers was investigated with respect to the type and amount of reactive monomers. The mechanical properties of varnishes produced were analysed. 13 refs. 

Rasor and Tischer (1998) have brought out the advantages of enzyme immobilization. Examples of penicillin-G to 6-APA, hydrolysis of cephalospwrin C into 7-ACA, hydrolysis of isosorbide diacetate and hydrolysis of 5-(4-hydroxy phenyl) hydantom are cited. De Vroom (1998) has reported covalent attachment of penicillin acylase (EC 3.51.11) from E.Coli in a gelatine-based carrier to give a water insoluble catalyst assemblase which can be recycled many times, and is suitable for the production of semi-synthetic antibiotics in an aqueous environment. The enzyme can be applied both in a hydrolytic fashion and a synthetic fashion. 6-APA was produced from penicillin-G similarly, 7-ADCA was produced from desa acetoxycephalosporin G, a ring expansion product of penicillin G. 

Later, Schopf et al. (67,68) found that the yield could be raised to 83% by using, at 25°C, dilute solutions buffered at pH 5 (physiological conditions). Despite this relatively high yield the reaction was not very suitable for the production of tropinone (124), especially in large scale, because of the lack of a convenient method to obtain succinaldehyde (140). This obstacle was later circumvented when it was found that succinaldehyde (140) could be replaced by its synthetic equivalent, 2,5-dimethoxytetrahydrofuran (143) (Scheme 3). 

There is a broad diversity of heterologous hosts for gene expression, and there is no best or universal host which is suitable for the production of all possible proteins. Nevertheless, many proteins can be expressed cheaply and successfully in Escherichia coli, which is still the most preferred host for heterologous production of proteins without posttranslational modifications. 

Vacuum was applied to shift the equilibrium forward by removal of the activated alcohol formed [30, 31, 37, 38]. In the enzymatic polycondensation of bis(2,2,2-trifluoroethyl) sebacate and aliphatic diols, the polymer with Mw of more than 1 x 104 was obtained using lipases CC, MM, PPL, and Pseudomonas cepacia lipase (lipase PC) as catalyst and lipase MM showed the highest catalytic activity [37]. Solvent screening indicated that diphenyl ether and veratrole were suitable for the production of the high molecular weight polyesters under vacuum. In the PPL-catalyzed reaction of bis(2,2,2-trifluoroethyl) glutarate with 1,4-butanediol in veratrole or 1,3-dimethoxybenzene, periodical vacuum method improved the molecular weight (Mw 4 x 104) [38]. 

You have to talk about propylene oxide and propylene glycol after ethylene oxide and glycol. Its not that the chemical configurations are so similar (they are), or that the process chemistry is about the same (it is). The Fact is that much of the propylene oxide is now made in plants originally designed and constructed to produce EO, not PO. As you read in the last chapter, the chlorohydrin route to EO was abandoned by the 1970s in favor of direct oxidation. At the same time, the EO producers found that the old EO plants were suitable for the production of PO and certainly the cheapest hardware available to satisfy growing PO demands. 

Although quartz crystals are suitable for the production of optical lenses, most lenses are manufactured from synthetically produced quartz due to the scarcity of good-grade large quartz crystals. 

In 1928, PVB, an polyacetal of PVA and but3ric aldehyde, was shown to be suitable for the production of laminated safety glasses [12], for which it is still used today. 

In commercial plants the volume of the reactors varies quite widely, and ranges typically between 4 and 6m (more rarely between 1 m and 10 m, or in rare cases even larger). As a rule of thumb, the annual capacity for a one-step synthesis process averages approximately 15-30 metric tons of product per 1 m reactor volume. Therefore, a production train, which is equipped with 4 and 6m reaction vessels, is suitable for the production of around 100 metric tons of a step per year. As illustrated in Figure 5.1, this corresponds to a typical production volume of an API. Whereas 45% of the top 200 drugs are produced in the volume range of 10-100 tons per year, the requirement for less than 25% of the APIs exceeds 100 tons per year. 

Lipases still offer the potential for an important range of applications since they are able to carry out the reactions of esterification, transesterification (acidolysis or alcoholysis), inter-esterification, or hydrolysis, often with high specificity or selectivity, suitable for the production of high-added-value molecules as shown in Example 1 above (stereospecific alkylation, acylation, or hydrolysis for the resolution of racemic mixtures of acids, alcohols or esters). 

The combination of deasphalting and sulfuric acid treating is suitable for the production of bright stocks of conventional viscosity index from heavy petroleum residua. 

Further, methods using phase transfer catalysts are suitable for the production of transparent poly(siloxane)/PC copolymers (27). As phase transfer catalyst a methyltributyl ammonium salt is used. 

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