Interpreting a Handbook Part 1 (Laboratory Manual)

 

By : James W Zubrick
Email: j.zubrick@hvcc.edu

You should look up information concerning any organic chemical you’ll be working with so that you know what to expect in terms of molecular weight, density, solubility, crystalline form, melting or boiling point, color, and so on. This information is kept in handbooks that should be available in the lab, if not in the library. Reading some of these is not easy, but once someone tells you what some of the fancy symbols mean, there shouldn’t be a problem. Many of the symbols are common to all handbooks, and are discussed only once, so read the entire section even if your handbook is different. There are at least four fairly popular handbooks and I’ve included sample entries of 1-bromobutane and benzoic acid, a liquid and a solid you might come across in lab, to help explain things.

CRC HANDBOOK

(CRC Handbook of Chemistry and Physics, CRC Press, Inc., Boca Raton, Florida.) Commonly called “the CRC” as in, “Look it up in the CRC.” A very popular book; a classic.

Entry: 1-Bromobutane (Fig. 11)

1. No. 3683. An internal reference number. Other tables in the handbook will use this number, rather than the name.

2. Name, . . . Butane, 1-bromo. You get a systematic name and a formula.

3. Mol. wt. 137.03. The molecular weight of 1-bromobutane.


4. Color,………Dots! This implies 1-bromobutane is a colorless liquid; nothing special really.

5. b. p. 101.6, 18.830. The normaling boiling point, at 760 torr, is 101.6° C. The 18.8 has a tiny superscript to tell you that 18.8°C is the boiling point at 30 torr.

6. m.p. — 112.4. The melting point of solid 1-bromobutane. Handbooks report only the TOP of the melting point range. You, however, should report the entire range.

7. Density. 1.275820/4. Actually, this particular number is a specific gravity. This is a mass of the density of the liquid taken at 20 °C referred to (divided by) the density of the same mass of water at 4°C. That’s what the tiny 20/4 means. Notice the units will cancel. A number without the modifying fraction is a true density (in g/ml) at the temperature given.

8. nD 1.440120. This is the index of refraction (see Chapter 22, “Refrac-tometry”) obtained using the yellow light from a sodium lamp (the D line). Yes, the tiny 20 means it was taken at 20°C.

9. Solubility. al,eth,ace,chl. This is what 1-bromobutane must be soluble in. There are a lot of solvents, and here are the abbreviations for some of them:

 

al alcohol eth ether
bz benzene chl chloroform
peth petroleum ether w water
aa acetic acid MeOH methanol
lig ligroin tmp30-11 carbon tetrachloride
to toluene

 

Some solvents have such a long tradition of use, they are our old friends and we use very informal names for them: alcohol. Ethyl alcohol; ethanol. ether.

Diethyl ether; ethoxyethane. pet. ether. Petroleum ether. Not a true ether, but a low boiling (3060 °C) hydrocarbon fraction like gasoline.

Ligroin. Another hydrocarbon mixture with a higher boiling range (60-90°C) than pet. ether. 10. Ref. Bl4258 Reference to listing in a set of German handbooks called “Beilstein.” Pronounce the German “ei” like the long i and stop yourself from saying “Beelsteen” or some such nonsense. 1-Bromobutane is in the fourth supplement (4), Volume 1 (Bl) on page 258.

Sample CRC entries from the 61st edition.

Fig. 11 Sample CRC entries from the 61st edition.

Entry: Benzoic Acid (Fig. 11)

There are a few differences in the entries, what with benzoic acid being a solid, and I’ll point these out. If I don’t reexamine a heading, see the explanation back in the 1-Bromobutane entry for details.

1. Color, . . . mcl If or nd. Monoclinic leaflets or needles. This is the shape of the crystals. There are many different crystalline shapes and colors and I can’t list them all—but here’s a few:

 

pi plates mcl monoclinic
nd needles rh rhombus
If leaves ye yellow
pr prisms pa pale

 

I’ve included #2532 (Benzoic acid, 2-acetamido) to show that you sometimes get a bonus. Here nd(aa) means you get needle-like crystals from acetic acid. Acetic acid (aa) is the recrystallization solvent (see Chapter 10, “Recrystallization”), and you don’t have to find it on your own. Thus, pa ye nd (al) means that pale yellow needles are obtained when you recrystallize the compound from ethanol.

2. Density. 1.0749130. This is an actual density of benzoic acid taken at 130 °C. There is no temperature ratio as there is for the specific gravity (1.265915/4).

Nostalgia

I’ve included the entries from the 43rd and 49th editions of the CRC to show you that not all things improve with age.

1. General Organization. The 43rd and 49th editions make use of boldface type to list parent compounds, and lighter type to list derivatives. Benzoic acid is a parent; there are many derivatives (Fig. 12). The 61st edition lists all compounds with the same weight (Fig. 11).

2. Solubility tables. Here the older editions really shine. The 43rd edition gives numerical solubility data for benzoic acid: 0.184,0.2718,2.275. These are the actual solubilities, in grams of benzoic acid per 100 g of water at 4, 18, and 75 °C, respectively. The butyl bromide (1-bromobutane) entry has helpful solubility indicators: i, insoluble in water; miscible in alcohol; miscible in diethyl ether.

Sample CRC entries from the 49th edition.

Fig. 12 Sample CRC entries from the 49th edition.

There are other abbreviations used for the solubility of a compound. Some of the more popular abbreviations are

tmp30-14 soluble tmp30-15 insoluble
tmp30-16 slightly soluble tmp30-17 miscible, mixes in all
tmp30-18 tmp30-19 proportions.
tmp30-20 solvent must be hot tmp30-21 very

 

What a big change from the 43rd to the 61st edition. Numerical solubility data missing, solubility indications gone, and even incomplete solubility reporting (Benzoic acid: chl, CC14, acet., me. al., bz, CS2-43rd ed.; where are CC14, me. al., and CS2 in the 61st?). The decrease in organizational structure, I can live with. But the new way of presenting the solubility data (what there is of it) is useless for many things you need to do in your lab. Reread the sample synthesis experiment (see Chapter 2, “Keeping a Notebook”). You need more useful solubility data for that experiment than you can extract from the most recent CRC Handbook. For my money, you want a fancy $17.50 doorstop, get a CRC 61st and up. You want useful information, get a CRC 60th and back. Or consult the handbook I want to talk about next.

LANGE’S

(Lange’s Handbook of Chemistry, McGraw-Hill Book Company, New York, New York.) A fairly well known, but not well used handbook. The entries are similar to those in the CRC Handbooks so I’ll only point out the interesting differences.

Sample CRC entries from the 41st edition. Sample CRC entries from the 41st edition.

Fig. 13 Sample CRC entries from the 41st edition.

Entry: 1-Bromobutane (Fig. 14)

1. Name. Butyl bromide(n). Here, 1-bromobutane is listed as a substituted butyl group much like in the 43rd CRC. The systematic name is listed under synonyms.

2. Beil. Ref. 1-119. The Beilstein reference; Volume 1, page 119, the original work (not a supplement).

tmp30-24_thumb[1]tmp30-25_thumb[1]

3. Crystalline form . . . Iq. It’s a liquid.

4. Specific gravity 1.27520/4. The tiny temperature notation is presented a bit differently, but the meaning is the same.

5. Solubility in 100 parts water. O.O610 0.06g of 1-bromobutane will dissolve in 100 g of water at 16 °C. After that, no more.

Table 7-4 PHYSICAL CONSTANTS OF ORGANIC COMPOUNDS

No. Name Synonym Formula Beil. Ref. Formula Weight
711 Benzoic

acid

tmp30-27 tmp30-28 IX-92 122.12
712 Na salt sodium benzoate tmp30-29 IX-107 162.12
Benznaphthalide 765 Benzoic acid sulfamide 5671-3

Table 7-4 PHYSICAL CONSTANTS OF ORGANIC COMPOUNDS

Beil. Formula
No. Name Synonym Formula Ref. Weight
1040 Butyl amine (sec) tmp30-30 tmp30-31 IV-160 73.14
1041 amine (iso) tmp30-32 tmp30-33 IV-163 73.14
1057 bromide (n) 1-bromo-butane tmp30-34 1-119 137.03
1058 bromide (sec) 2-bromo-butane tmp30-35 1-119 137.03
1059 bromide (/so) 1 -Br-2-Me-propane tmp30-36 1-126 137.03
1060 bromide (tert) 2-Br-2-Me-propane tmp30-37 1-127 137.03
Butyl borate 6117 Butyl carbinol (iso) 406 Butyl carbinol (tert) 410
Butyl carbamide 1138-9 Butyl carbinol (sec) 411 Butyl carbitol 2232
Butyl carbinol (n) 404

Fig. 14 Sample entries from Lange’s 11 th edition. Entry: Benzoic Acid (Fig. 14)

1. Melting point. subl> 100. Benzoic acid starts to sublime (go directly from a solid to a vapor) over 100 °C, before any crystals left melt at 122.4°C.

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