Effective Bench Work

As I said, I first need to emphasize underlying principles rather strongly. Now, with that behind us, we are in a much better position to understand this particular chapter. 

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A knowledge of the physico-chemical principles of solvent effects is required for proper bench-work. Therefore, a description of the intermolecular interactions between dissolved molecules and solvent is presented first, followed by a classification of solvents derived therefrom. Then follows a detailed description of the influence of solvents on chemical equilibria, reaction rates, and spectral properties of solutes. Finally, empirical parameters of solvent polarity are given, and in an appendix guidelines to the everyday choice of solvents are given in a series of Tables and Figures. 

A typical laboratory that has been in operation for some time usually has run out of space for optimum operation. In some cases, the space may be there but cannot be utilized to full advantage. Work benches gradually get covered with permanent equipment set-ups, leaving little room for other work. Lack of storage space for supplies and samples becomes the rule rather than the exception. Adequate room for a desk, bookcase, or typewriter has often been overlooked. As more personnel is added, these problems become critical. Overcrowding also has a serious effect on safety. 

Atlantic Richfield Company has reported strains of Pseudomonas sp. CB1 (ATCC 39381) [108] and Acinetobacter species CB2 [109] (ATCC 53515) to be effective for the removal of sulfur from organic molecules found in petroleum, coal, etc. In fact, the aerobic and heterotrophic soil microorganisms Pseudomonas CB1 and Acinetobacter CB2 were reported to convert thiophene sulfur into sulfate, using a bench-scale continuous bioreactor. The direct contact with Illinois 6 coal reduced the organic sulfur content in about 40% to 50%. As already mentioned, most of this work was carried out on coal. Further work was not pursued probably due to decrease in coal usage or due to the economics of the processes. 

In this chapter, we consider nonideal flow, as distinct from ideal flow (Chapter 13), of which BMF, PF, and LF are examples. By its nature, nonideal flow cannot be described exactly, but the statistical methods introduced in Chapter 13, particularly for residence time distribution (RTD), provide useful approximations both to characterize the flow and ultimately to help assess the performance of a reactor. We focus on the former here, and defer the latter to Chapter 20. However, even at this stage, it is important to realize that ignorance of the details of nonideal flow and inability to predict accurately its effect on reactor performance are major reasons for having to do physical scale-up (bench —> pilot plant - semi-works -> commercial scale) in the design of a new reactor. This is in contrast to most other types of process equipment. 

It is now clear that asymmetric catalytic hydrogenation is rather successful. However, the initial research work of Sharpless [5] in the asymmetric epoxidation, followed by the results of Jacobsen et al. [6] opened large opportunities for liquid-phase asymmetric oxidation. Sharpless epoxidation has been widely applied in bench-scale organic synthesis, and more recently, salene derivatives emerged among the most effective catalysts in this reaction [7,8],... 

Below are two types of steam generators that you can build. The top one utilizes gas and the bottom one uses electricity for power. Every work bench needs steam. It is very safe for heating and very effective for cleaning glassware, etc. 

Fixtures within the room (e.g. work benches, chairs, equipment, etc.) should be kept to a minimum, and ideally be designed and fabricated from material that facilitates effective cleaning (e.g. polished stainless steel). The positioning of such fixtures should not hinder effective cleaning processes. Pipework should be installed in such a way as to allow effective cleaning around them and the presence of uncleanable recesses must be avoided. All corners and joints between walls and ceilings or floors are rounded, and equipment with movable parts (e.g. motors, pumps) should be encased. 

Bob wants to tear out the benches, sinks, and hood in our central work room and replace them with office furniture to better accommodate our burgeoning staff of junior associates, their desks, their file cabinets, and desktop computers. Knowing how much more expensive, hence valuable, wet lab space is than dry, I am resisting this change vigorously even as the pressure mounts. Bob says, Just cut off the pipes and cap them, when I ask how he intends to effect the change. 

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