Definition and relationship between conversion rate and yield
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I’m encountering a small issue while working on an environmental impact assessment project in the chemical industry, and I’d like to ask those who work in this field: 1. I can understand the definition of conversion rate from books, but I’m not clear about the definition of yield; it is said to be \"the percentage of the target product produced, calculated based on the amount of reactants used.\" That is, yield = (amount of product formed / amount of reactant fed) × 100%. ” 2. From research, it is known that the relationship between yield, conversion rate, and selectivity is as follows: Yield = Conversion Rate × Selectivity. But what exactly is selectivity? Could a colleague in the chemical industry please explain this, preferably with a simple example?
Selectivity refers to the extent to which a given raw material can be converted into different products through several distinct reactions; it is expressed as the fraction of the raw material that is transformed into a specific product, that is, the number of moles of the specific product actually produced divided by the number of moles of the same product that could theoretically be produced from the amount of raw material used.
Chemical reaction engineering books explain it in great detail, with many examples as well; you should take a look.
The conversion rate is how much of the raw material you put in compared to how much is converted in the end. Yield is the amount of target product obtained from a certain amount of raw material used.
(1) Conversion rate: The extent to which a chemical reaction proceeds is often expressed by the conversion rate, which refers to the percentage of a particular reactant that has been converted in the chemical reaction. The conversion rate is applicable to the reactants. If there is more than one reactant and they are not mixed in the ratio specified by the stoichiometric coefficients, it is common to use the reactant that is not in excess to calculate the conversion rate. (2) Selectivity: Selectivity refers to the proportion of the amount of raw material consumed to produce a particular desired reaction product, out of the total amount of raw material that has been converted. (3) Yield: It represents the percentage of the amount of raw material (or the amount of the desired product obtained) that serves as the target product after passing through the reactor, relative to the amount of raw material. Yield equals conversion rate multiplied by selectivity.
Thank you to the expert on floor 5; I understand now!
The selectivity here refers to the ratio of the amount of target product that can be used to the total amount converted, after the raw material is transformed into the target product. In other words, the yield = (amount of product / total amount of raw material) = ((total amount converted – amount lost) / total amount of raw material) = conversion rate – loss rate
The conversion rate refers to the percentage of raw material that is converted into product, which is the amount of product produced divided by the amount of raw material. Yield refers to the ratio of the actual amount of product obtained from a given amount of raw material to the theoretical amount of product that could be obtained. The selectivity here refers to the ratio of the amount of target product that can be used to the total amount converted, after the raw material is transformed into the target product.
1. Conversion rate The conversion rate is an indicator of the extent of reaction of the reactants. It is defined as the percentage of a reactant (A) that participates in the reaction, relative to the amount added. 2. Yield The yield is an indicator of how much of the reactants that participate in the reaction are converted into the desired product. The percentage of the actual yield of a product relative to the theoretical yield (calculated based on the amount of a certain reactant that participates in the reaction). In other words, it is the percentage of a certain reactant consumed to produce the desired product, relative to the total amount of that reactant that participates in the reaction. 3. Yield The yield is a comprehensive indicator that shows how much of the reactants participated in the chemical reaction and how much was involved in the main reaction. The so-called yield refers to the percentage of the actual amount produced of a certain product, compared to its theoretical yield (calculated based on the amount of that reactant used). In other words, it is the percentage of the amount of a certain reactant consumed to produce the desired product, relative to the total amount of that reactant added. Yield = Yield rate × Conversion rate. 4. Selectivity (selectivity of the catalyst) The ability of a catalyst to drive a chemical reaction in the desired direction, thereby yielding the target product, is known as the catalyst’s selectivity. The selectivity of a catalyst is generally expressed by the yield of the desired product (the main product).
Yield refers to the ratio of the product we expect to obtain to the reactants. The conversion rate includes unwanted by-products; we aim to increase the yield, not just focus on the conversion rate, so it is related to catalyst selectivity. Based on my memories from school, it’s explained in very simple terms
This question isn’t difficult, that’s what I think