LAB NOTEBOOKS. If you used a lab notebook in general chemistry or first-semester organic chemistry, many of the same guidelines apply.

Transcription

1 LAB OTEBOOKS If you used a lab notebook in general chemistry or first-semester organic chemistry, many of the same guidelines apply. Formatting guidelines: Use pen for all notebook entries, never pencil. Write neatly and legibly. Cross through mistakes with 1-2 lines, so the original mistake is legible. Don t scribble out a mistake. Write on consecutive, numbered pages on the right side only. ever tear out or leave blank pages (draw a diagonal line through any blank pages in between entries). Have the instructor initial your work to verify that the entry was completed in lab. Procedural guidelines: Write procedures in past-tense third-person (not I added 50 ml or Add 50 ml but instead 50 ml was added ). An example is as follows: 13.6 g of ortho-hydroxyacetophenone (white solid) was added to a round-bottomed flask along with 21.1 g of benzoyl chloride (clear liquid) and 20 ml pyridine (clear liquid). The reaction was heated to 50 C for 15 minutes. The mixture was poured into 600 ml of 3 % HCl containing 200 g of crushed ice. The solid product was collected via suction filtration and washed with 20 ml methanol to afford 22.5 g product (white solid). Sufficient details should be present that another chemist familiar with standard procedures (distillation, reflux, etc.) could replicate the work. For example, chemists know what TLC entails, but the specific solvent needs to be recorded as this varies with each experiment. Interweave procedures with the data in short paragraphs. If a reagent is used or product obtained, it is expected that the mass (or volume) is written immediately following the procedure where it is mentioned. It should not have to be searched for: not earlier in a data table, or later in the entry or in the conclusion. Short paragraphs should be used to aid in readability. For large amounts of data, data tables may be used for organization (e.g. to summarize GC information). Entries should be objective, and interpretations should be left to the conclusion. Page 4

2 Differences between first-semester and second-semester: Include a graphical table of contents, which uses the page number and reaction scheme (structures) for each lab experiment. Write the introduction and conclusion in third-person ( In this lab aspirin will be synthesized and analyzed by MR or It was shown in this lab that ). An attempt should be made to fill out the notebook near to when the procedure is actually performed (e.g. within 30 minutes or so). In practice, however, some experiments are time-intensive and lack large blocks of time where notebook entries may be made. In those cases, take good notes on the procedural instructions, and complete the notebook entry as soon as possible (shortly after lab or at the most later that day). Vital observations may be forgotten if too much time is spent before recording an entry. As some experiments are time-intensive, only one instructor initial is required per multi-day experiment. This should be obtained on the final day of the experiment, and the instructor will require that the entry is up to date and complete before signing. Page 5

3 LAB OTEBOOK FORMAT SAMPLE TABLE OF COTETS A graphical table of contents must be present in the front of your lab notebook, with page number and reaction scheme for each experiment. If using your lab notebook from first-semester organic chemistry, the page numbers for CHEM 22 can start mid-way after the first-semester experiments. If space was not reserved for the table of contents, it is acceptable to tape in a blank page to the front of your book. In some experiments the product may not be known ahead of time. In these situations, you may want to leave the product blank until you are certain of the correct structure. The table of contents is expected to be updated by the time of the periodic checks of your notebook. Page # Reaction 11 H 1. ah 2. Cl DMF / DMSO 13 H 1. ah 2. Cl DMF / DMSO nbuli 2. Bu 3 SnCl DME SnBu 3 17 OH nbuli nbuli 2. I 2 Et 2 O I 21 SnBu 3 I Pd(PPh 3 ) 2 Cl 2 THF 26 1M aoh iproh / H 2 O H Page 6

4 SAMPLE LAB OTEBOOK ETRY Leave g, vol, mmol blank at first to fill in with actual values during lab. Leave space for th yield. Have Intro and data table skeleton ready before lab. A mass (yield) is expected immediately where the procedure states the product is isolated. The default is to use the analytical balance. Page 7

5 o need to write TLC was run If you list TLC data, obviously it was run. Copy TLC to scale. Best to leave interpretation for the conclusion, but OK to write brief notes if something is worth pointing out. Only one signature is needed per experiment (given on the last day of the expt: you must be caught up by then!) Page 8

6 SAMPLE POSTIG OF SPECTRA There will be many spectra to include with each experiment, and they do not need to be posted one per page. A good way to organize the spectra is to fold and overlay them in a staggered fashion on a single page, and staple or tape them in. The top of each paper could be annotated to provide organization. It is acceptable to post the spectra for an experiment on a page that follows the conclusion. GC Spectrum Pg 14 IR Spectrum 1 H MR Spectrum of Benzaldehyde 1 H MR Spectrum of Benzil Product Page 9