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The product is isolated from the mixture by the following work-up: [3] Synthesis of 4-methylcyclohexene with work-up step in red. A concentrated solution of sodium chloride in water, known as a brine solution, is added to the mixture and the layers are allowed to separate. The brine is used to remove any acid or water from the organic layer.
Thermodynamic cycles may be used to model real devices and systems, typically by making a series of assumptions to reduce the problem to a more manageable form. [2] For example, as shown in the figure, devices such a gas turbine or jet engine can be modeled as a Brayton cycle. The actual device is made up of a series of stages, each of which is ...
In analytical chemistry, sample preparation (working-up) refers to the ways in which a sample is treated prior to its analyses. Preparation is a very important step in most analytical techniques, because the techniques are often not responsive to the analyte in its in-situ form, or the results are distorted by interfering species.
The process steps may be sequential in time or sequential in space along a stream of flowing or moving material; see Chemical plant. For a given amount of a feed (input) material or product (output) material, an expected amount of material can be determined at key steps in the process from empirical data and material balance calculations.
In the hospital laboratory, for example, difficulties arise with the "staunch adherence to traditional laboratory practices, complexity of workflow, and marked variability in sample numbers." [7] In pharmaceutical and biopharmaceutical labs, "the limiting belief" that procedures are so different that lean won't work often slow down adoption. [8]
In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical reaction occurs. [1] A chemical mechanism is a theoretical conjecture that tries to describe in detail what takes place at each stage of an overall chemical reaction. The detailed steps of a reaction are not observable in most cases.
An ore extraction process broken into its constituent unit operations (Quincy Mine, Hancock, MI ca. 1900) In chemical engineering and related fields, a unit operation is a basic step in a process. Unit operations involve a physical change or chemical transformation such as separation, crystallization, evaporation, filtration, polymerization ...
In lean thinking, inappropriate processing or excessive processing of goods or work in process, "doing more than is necessary", is seen as one of the seven wastes (Japanese term: muda) which do not add value to a product. [9] [10]