Priority order

When similar atoms are attached to a particular atom, priority order is determined by the nature of the atoms further away. 

X in acid derivatives Name of X (in priority order fluoride, chloride, bromide, iodide, cyanide, azide then the sulfur and selenium analogs)... 

A hierarchy of four main strategies can be used to reduce the waste within a process. This hierarchy establishes die priority order in which waste management activities should be employed ... 

Rules and filters do exceptions exist Off course they do. Common sense is required. There is a natural priority order in drug discovery decision making. Clinical information trumps all. Next in importance is high quality experimental evidence, e.g., in vivo animal experiments. Rules and filters come into play when clinical and experimental data is lacking. 

If several processes require PrHAs, the PrHAs must be prioritized. A preliminary hazard analysis (PHA) may be used to determine and document the priority order for conducting PrHAs. At a minimum, the PSM Rule requires the prioritization to consider the potential severity of a chemical release, the number of potentially affected employees, and the operating history of the process, including the frequency of past chemical releases and the age of the process. 

OSHA/USEPA requires employers, such as the chemical industry service sector, to perform an initial process hazard analysis (PHA) on processes covered by PSM/RMP standards. The PHA must be appropriate to the complexity of the process and must identify, evaluate, and control the hazards involved in the process. Employers are required to determine and document the priority order for conducting process hazard analyses based on a rationale that includes such considerations as extent of the process hazards, number of potentially affected employees, age of the process, and operating history of the process. 

On examining this compound (Sect. IV-B), we found an enantiomorphic difference between the ring ligands of C(l). It can be used to derive a priority order for the proximal carbon atoms of C(l). By provisionally assigning them different priorities one can determine which preference order induces the R, and which the S, configuration at C(4). This induced sense of chirality is mere... 

In all cases in which we determined specific descriptors, we assumed an alphabetical priority order of the unspecified ligands (g > h > i.. . ) and R chirality for any ligand marked. ... 

On the other hand, fuel cell applications and the market will determine the priority order of these requirements. The major markets or applications where fuel cells have been applied or have a large potential to be applied include [1] ... 

These recommendations are not listed in a priority order, but many could be followed in parallel or simultaneously. In general, the recommendations presented by Heck et al. are still germane to research needs with respect to oxidant pollutants. 

In the third model (finite chain with different terminal groups) no reflection symmetry element exists in the Fischer projection. The individual macromolecules are, therefore, chiral and all the tertiary atoms are asymmetric and different. The stereochemical notation for a single chain, depending on the priority order of the end groups, can be R, R2, R. . . R -2, R -i, Rn or R, R2, R3... 

Dihydroxypropanoic acid Priority order 1 to 4 is in clockwise direction... 

A priority order (note that this can change because of some real-time changes in the system, and thus this station must be able to cope with this task too). 

A chiral carbon is designated as being R or S as follows. The carbon is viewed from the direction opposite to the ligand of lowest priority. If the priority order of the remaining three ligands decreases in a clockwise direction, the absolute configuration of the molecule is said to be R (Latin, rectus = right). If it decreases in the counterclockwise direction it is said to be S (Latin, sinister = left. For example ... 

The first atoms in two or more substituents often are identical, in which case it is necessary to explore further and compare the atomic numbers of the second attached atoms. Precedence is given to the substituent with a second atom of higher atomic number. For example, in 2-butanol, CH3CH (OH)CH2CH3, two of the groups at the chiral atom have carbon as the first atom. We therefore must compare the other atoms bonded to these two carbons. It is convenient to represent the arrangement at the chiral atom as shown in 7, where the first atoms are shown attached to the chiral center and the second atoms are listed in their priority order thus, (C,H,H) for ethyl and (H,H,H) for methyl ... 

Action Decide whether the design project should proceed to the next stage. If no, list all the reasons (in order ofpriority) and indicate what changes (if any are possible) would reverse this decision. If yes, list all the assumptions/restridions upon which this dedsion is based (in priority order). 

Most of the state laws set aside a certain portion of the funds for cleaning up major abandoned tire dumps. As a first step, some states develop an inventory of the tire dumps in the state. They may then rank them in priority order for clean-up. Criteria such as the size of the dumps, and proximity to highly populated areas or to critical natural resources may be used in determining which dumps are cleaned up... 

Know the meaning of stereogenic carbon atom, stereogenic center, R-S convention, priority order, E-Z convention, Fischer projection. 

Know the rules for establishing priority orders of groups in the R-S convention. 

Given a compound with a stereogenic center, assign the priority order of groups attached to it. 

Then fill in the groups in priority order, counterclockwise (S),... 

In each case, write down the groups in the proper priority order. Then view the... 

The stereogenic center is marked with an asterisk. The priority order of groups at this center is... 

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