Batch reactor pharmaceuticals

From diese various estimates, die total batch cycle time t(, is used in batch reactor design to determine die productivity of die reactor. Batch reactors are used in operations dial are small and when multiproducts are required. Pilot plant trials for sales samples in a new market development are carried out in batch reactors. Use of batch reactors can be seen in pharmaceutical, fine chemicals, biochemical, and dye industries. This is because multi-product, changeable demand often requues a single unit to be used in various production campaigns. However, batch reactors are seldom employed on an industrial scale for gas phase reactions. This is due to die limited quantity produced, aldiough batch reactors can be readily employed for kinetic studies of gas phase reactions. Figure 5-4 illustrates die performance equations for batch reactors. 

In the pharmaceutical industry, and to some extent the fine chemicals industry, an important advantage of a batch reactor is traceability. The product from a particular batch will have a uniform consistency, and can be uniquely labelled and readily traced. In contrast, the product from a continuous process may change gradually over time, and it is therefore more difficult to trace a particular impurity or fault in the material. Batch reactors are, however, rarely the most efficient in terms of throughput and energy use when the reaction kinetics are fast. Batch systems are also much more labour intensive than continuous processes. 

As noted above, stirred batch reactors are the most common type of reactor used for the production of fine and pharmaceutical chemicals. This is partly to do with tradition and partly with the need to produce a flexible reactor design in which a whole range of products can be made. Spinning... 

Batch reactors are often used for liquid phase reactions, particularly when the required production is small. They are seldom employed on a commercial scale for gas-phase reactions because the quantity of product that can be produced in reasonably sized reactors is small. Batch reactors are well suited for producing small quantities of material or for producing several different products from one piece of equipment. Consequently they find extensive use in the pharmaceutical and dyestuff industries and in the production of certain specialty chemicals where such flexibility is desired. When rapid fouling is encountered or contamination of fermentation cultures is to be avoided, batch operation is preferable to continuous processing because it facilitates the necessary cleaning and sanitation procedures. 

Consequently, we consider that the industrial scale technological management of microwave assisted chemical reaction is no compatible with batch reactors coupled with multimode applicators. Some typical processes with a systematic decrease of the dielectric losses of the concerned reactant, such as filtration and drying of mineral or pharmaceutical powders are compatible with multimode applicators. To our knowledge, the only industrial batch microwave device is the microwave variant of the Turbosphere ( all in one solution mixer/granulator/dryer designed by Moritz... 

These two factors mean the semi-batch reactor is a commonly-used reactor type in the fine chemicals and pharmaceutical industries. It retains the advantages of flexibility and versatility of the batch reactor and compensates its weaknesses in the reaction course control by the addition of, at least, one of the reactants. 

It should be borne in mind that the SDR is most effectively exploited when it is run on a continuous basis. The industrial units constructed to date have had disc diameters up to 30 cm and have been capable of processing around 30 g/s of feedstock. This corresponds to a continuous annual output of (e.g., polymer) 1000 tons/year. For a typical pharmaceutical product, a 15-cm disc could process about 7 g/s, equivalent to an annual output of 200 tons. With conventional stirred-vessel technology, a roughly equivalent unit to the 30-cm SDR is a 2000-L batch reactor... 

Batch reactors are used extensively in industries where only small quantities of product are made, such as pharmaceuticals. For small amounts, the economy of scale hurts flow reactors, which typically have a higher initial investment for controls and plumbing. 

Commercial-scale batch reactors are generally used for small-lot or specialty items. This includes chemicals such as paints, dyes, and pharmaceuticals. Batch reactors are very simple and flexible. Vessels used to make one compound can be washed and reused to make other products. The ease of cleaning and maintaining batch reactors along with low capital investment and low instrumental costs... 

Fatty acid methyl and ethyl esters derived from vegetable oils are considered to be a promising fuel for direct injection diesel engines. Moreover, they are valuable compounds for the production of fine chemicals for food, pharmaceutical and cosmetic products. Leclercq et a/.1711 showed that the methanolysis of rapeseed oil can be carried out with MgO, although its activity depends strongly on the pretreatment temperature of this oxide. Thus, with MgO pretreated at 823 K and a methanol to oil molar ratio of 75 at methanol reflux, a conversion of 37 % with 97 % selectivity to methyl esters was achieved after 1 h in a batch reactor. 

Monolithic supports are commonly used for environmental applications and will be discussed in more detail later.-5 Batch reactors are used mostly for small-scale production such as the hydrogenation of intermediates in the production of medicines in the pharmaceutical industry. The catalyst powder is mixed in a precise amount of reactant in a pressurized-stirred autoclave. A gaseous reactant, usually H2, is introduced at elevated pressures and the reaction proceeds with continuous monitoring of the H2 consumed. The catalyst is separated from the product via filtration and is often used again depending on its retained activity and selectivity. 

Hydrogen reactions play an important role in the production of fine chemicals, vitamins and pharmaceutical products. In recent years continuous reactors rather than the traditional batch reactors are becoming more interesting. 

Various aspects of the effect of process scale-up on the safety of batch reactors have been discussed by Gygax [7], who presents methods to assess thermal runaway. Shukla and Pushpavanam [8] present parametric sensitivy and safety results for three exothermic systems modeled using pseudohomogenous rate expressions from the literature. Caygill et al. [9] identify the common factors that cause a reduction in performance on scale-up. They present results of a survey of pharmaceutical and fine chemicals companies indicating that problems with mixing and heat transfer are commonly experienced with large-scale reactors. 

A pharmaceutical product, P, is made in a batch reactor. The reactor effluent goes through a purification process to yield a final product stream and a waste stream. The initial charge (feed) to the reactor and the final product are each weighed, and the reactor effluent, final product, and waste stream are each analyzed for P. The analyzer calibration is a series of meter readings, R. corresponding to known mass fractions of P, xp. 

Reactors do not always run at steady state. In fact, many pharmaceuticals are made in a batch mode. Such problems are easily solved using the same techniques presented above because the plug flow reactor equations are identical to the batch reactor equations. Even CSTRs can be run in a transient mode, and it may be necessary to model a time-dependent CSTR to study the stability of steady solutions. When there is more than one solution, one or more of them will be unstable. Thus, this section considers a time-dependent CSTR as described by Eq. (8.51) ... 

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