DETERMINING THE LABORATORY-REACTOR SIZE NEEDED FOR SEEDING A BIOLOGICAL REACTION

SIZING OF BIO-REACTOR EXAMPLE AND TUTORIALS

Assuming a minimum 12% inoculum volume, what size of laboratory vessel would be required to initiate the seeding of a 20,000-L full-scale cell-culture bioreactor?

Calculation Procedure

1. Determine the size of reactor that would be required to seed the 20,000-L bioreactor. Since the seed volume must represent 12% of the vessel before reaction starts, the bioreactor being specified in this step would have to have a size 12% that of the 20,000-L bioreactor, or (0.12)(20,000), or 2400 L.

2. Determine the size of bioreactor needed to seed the 2400-L bioreactor of Step 1. Applying the same logic as in step 1, we see that the bioreactor being sought in this second step must be sized at 12% of 2400 L, or (0.12)(2400), or 288 L.

3. Repeat Step 2 successively until a bioreactor of reasonable laboratory volume is reached. Twelve percent of 288 L is 34.6 L; then, 12% of 34.6 is 4.15 L; and 12% of 4.15 L is 500 ml. Thus, a 4.15-L laboratory vessel can be used if available.

Otherwise, use a 500-ml vessel. The contents of the 500-ml vessel provide seeding for the 4.15-L vessel; the contents of the latter vessel then seed the 34.6-L bioreactor; the contents of this latter then seed the 288-L bioreactor; and so on.

ESTERIFICATION BASIC INFORMATION AND TUTORIALS

A variety of solvents, monomers, medicines, perfumes, and explosives are made from esters of nitric acid. Ethyl acetate, n-butyl acetate, iso-butyl acetate, glycerol trinitrate, pentaerythritol tetranitrate (PETN), glycol dinitrate, and cellulose nitrate are examples of such reactions.

Ester manufacture is a relatively simple process in which the alcohol and an acid are heated together in the presence of a sulfuric acid catalyst, and the reaction is driven to completion by removing the products as formed (usually by distillation) and employing an excess of one of the reagents. 

In the case of ethyl acetate, esterification takes place in a column that takes a ternary azeotrope. Alcohol can be added to the condensed overhead liquid to wash out the alcohol, which is then purified by distillation

and returned to the column to react.

Amyl, butyl, and iso-propyl acetates are all made from acetic acid and the appropriate alcohols. All are useful lacquer solvents and their slow rate of evaporation (compared to acetone or ethyl acetate) prevents the surface of the drying lacquer from falling below the dew point, which would cause condensation on the film and a mottled surface appearance (blushing). 

Other esters of importance are used in perfumery and in plasticizers and include methyl salicylate, methyl anthranilate, diethyl-phthalate, dibutyl-phthalate, and di-2-ethylhexyl-phthalate.

Unsaturated vinyl esters for use in polymerization reactions are made by the esterification of olefins. The most important ones are vinyl esters: vinyl acetate, vinyl chloride, acrylonitrile, and vinyl fluoride. The addition reaction may be carried out in either the liquid, vapor, or mixed phases, depending on the properties of the acid. 

Care must be taken to reduce the polymerization of the vinyl ester produced. Esters of allyl alcohol, e.g., diallyl phthalate, are used as bifunctional polymerization monomers and can be prepared by simple esterification of phthalic anhydride with allyl alcohol. 

Several acrylic esters, such as ethyl or methyl acrylates, are also widely used and can be made from acrylic acid and the appropriate alcohol. The esters are more volatile than the corresponding acids.