Organikum
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Benzoic Acid and its salts
I believe this compound is worth its own thread.
Found this on the net for a start:
http://18.1911encyclopedia.org/B/BE/BENZOIC_ACID.htm
BENZOIC ACID, C6H6O2 or C6H5COOH, the simplest representative of the aromatic acids. It occurs naturally in some resins, especially in gum benzoin
(from Styrax benzoin), in dragons blood, and as a benzyl ester in Peru and Tolu balsams. It can be prepared by the oxidation of toluene, benzyl
alcohol, benzaldehyde and cinnamic acid; by the oxidation. of benzene with manganese dioxide and concentrated sulphuric acid in the cold (L. Carius,
Ann. 1868, 148, p. 51); by hydrolysis of benzonitrue (?) or of hippuric acid; by the action of carbon dioxide on benzene in the presence of aluminium
chloride (C. Friedel and J. M. Crafts, Ann. chini. p/iys. 1888 , 14, p. 441); by the action of carbon dioxide on monobrombenzene in the presence of
sodium; by condensing benzene and carbonyl chloride in presence of aluminium chloride, the benzoyl chloride formed being subsequently hydrolysed; and
similarly from benzene and chlorformamide :
C6H6 +ClCONH1 = HCl+C6H5CONH
the benzamide being then hydrolysed. It may also be prepared by boiling benzyl chloride with dilute nitric acid (G. Lunge, Berichite, f877, 10, p.
1275); by fusing sodium benzene sulphonate with sodium formate: C1H5SO,NaH-HCO2Na=s C6H5COONa+ NaHSO1 by heating calcium phthalate with calcium
hydroxide to 3300_3500 C.; by heating benzotrichloride with water in a sealed tube, and from the hippuric acid which is found in the urine of the
herbivorae. For this purpose the urine is concentrated and the hippuric acid precipitated by the addition of hydrochloric acid; it is then. filtered
and boiled for some time with concentrated hydrochloric acid, when it is hydrolysed into benzoic and amido-acetic acid. It is made commercially by
boiling benzotrichloride (obtained from toluene) with milk of lime, the calcium benzoate so obtained being then decomposed by hydrochloric acid
2C6HfCC1, +4Ca(OH), = (C6H5COO)zCa +3CaC1, +4H10.
Benzoic acid crystallizes in glistening leaflets (from water) which melt at 121.4 C. and boil at 249.2 C. (H. Kopp). Its specific heat is o1946. It
sublimes readily and is volatile in steam. It is readily soluble in hot water and the ordinary organic solvents, but is only slightly soluble in cold
water. When heated with lime, it is decomposed, benzene being formed; if its vapours are passed over heated zinc dust, it is converted into
benzaldehyde (A. Baeyer, Ann. 1866, 140, p. 296). Distillation of its calcium salt gives benzophenone (q.v.) with small quantities of other
substances, but if the calcium salt be mixed with calcium formate and the mixture distilled, benzaldehyde is produced. By the action of sodium amalgam
on an aqueous solution of the acid, benzyl alcohol, tetrahydrobenzoic acid and hexahydrobenzoic acid are formed. The salts of benzoic acid are known
as the benzoates and are mostly soluble in water. They are readily decomposed by mineral acids with the production of benzoic acid, and on addition of
ferric chloride to their neutral solutions give a reddish-brown precipitate of ferric benzoate.
Benzoic anhydride, (C6H5CO),O, is prepared by the action of benzoyl chloride on sodium benzoate, or by heating benzoyl chloride with anhydrous oxalic
acid (R. Anschutz, Ann. 1884, 226, p. 15). Itcrystallizesinneedles, meltingat42C., andboiling at 36oC. It is insoluble in water but readily soluble in
alcohol and ether.
Benzoyl chloride, C6H1COC1, is formed by distilling a mixture of phosphorus pentachloride and benzoic acid; by the action of chlorine on benzaldehyde,
or by passing a stream of hydrochloric acid gas over a mixture of benzoic acid and phosphorus pentoxide heated to 200C. (C. Friedel, Ber. 1869, 2, p.
80). It is a colorless liquid of very unpleasant smell, which boils at 198 C., and solidifies in a freezing mixture, the crystals obtained melting at
r C. It shows all the characteristic properties of an acid chloride.
Ethyl benzoate, C6H5COOC1H5, is best prepared by boiling benzoic acid and alcohol with a small quantity of sulphuric acid for some hours (E. Fischer
and A. Speier, Berichte, 1896, 28, p. 3252). It is a colorless liquid of boiling point 213 C.
Bcnzamide, C6H5CONH1, is prepared by the action. of benzoyl chloride on ammonia or ammonium carbonate, or from ethyl benzoate and ammonia. It
crystallizes (from water) in glistening leaflets which melt at 130 C. and boil at 288 C. Its silver salt behaves as if it were the salt of an imido
benzoic acid, since it yields benzimido ethyl ether C6H5C(:NH)OC,Hi with ethyl iodide (J. Tafel and C. Enoch, Berichite, 1890, 23, p. 1550).
Chlor-, brom-, iodo- and fluor-benzoic acids are known and can be obtained by oxidizing the corresponding halogen toluenes, or from the amido acids,
or by substitution. Nitration of benzoic acid gives chiefly meta-nitro-benzoic acid. The ortho- and para-nitro-benzoic acids can be obtained by
oxidizing orthoand para-nitro-cinnamic acids. Ortho-amino-benzoic acid, C61-I4NH2.COOH (anthranilic acid), is closely related to indigo (q.v.),
Gum benzoin, which contains from 12 to 20 % of benzoic acid, is used in medicine as the essential constituent of benzoated lard, Adeps benzoatus,
which owes its antiseptic properties to benzoic acid; and in friars balsam, Tinctura benzoini composita, which is an ancient and valuable medicament,
still largely used for inhalation in cases of laryngitis, bronchitis and other inflammatory or actually septic conditions of the respiratory tract. It
owes its value to the benzoic acid which it contains. A fluid drachm of friars balsam may be added to a pint of water at a temperature of about 140
F., and the resultant vapour may be inhaled from the spout of a kettle or from a special inhaler. Benzoic acid itself, ammonium benzoate and sodium
benzoate are all administered internally in doses of from five to thirty grains. The ammonium salt is most often employed, owing to the stimulant
character of the ammonium base. The acid itself is a powerful antiseptic. When administered internally, it causes the appearance of hippuric acid in
the urine. This is due to its combination in the body with glycocoll. The combination probably occurs in the kidney. The hippuric acid in the urine
acts as a stimulant and disinfectant to the urinary mucous membrane. Benzoic acid is also excreted by the bronchi and tends to disinfect and stimulate
the bronchial mucous membrane. Hence the value of friars balsam. The acid and its salts are antipyretic and were used in Germany instead of
salicylates in rheumatic fever. But the most important fact is that ammonium benzoate is largely usedoften in combination with urinary anodynes such
as tincture of hyoscyamusas a urinary antiseptic in cases of cystitis (inflammation of the bladder) and pyelitis (inflammation of the pelvis of the
kidney).
Sorry the article has a lot of mistakes from scanning in special in the formulas, I will try to clean it up later.
Nevertheless interesting stuff with nice references.
Never forget: 1911 ! 
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vulture
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The tidbit about benzaldehyde is quite interesting.
Do you have any information on copperbenzoate? I once prepared this compound but I couldn't find much useful info.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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Mephisto
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Copper benzoate
Unfortunately I couldn't find anything about its properties, if it's that what is useful for you. Only a preparation again. Maybe
some Beilstein-Crossfire-users have more success. (It's easier to do a search with the CAS-number of copper benzoate [14067-34-6], than with its
name.)
Here the preparation:
The reactions of Bz2O with excess CuO are carried out in cyclohexane at several temps. for 1 hr. The conversion of Bz2O into a Cu benzoate, which is
different from Cu(I) or (II) benzoates, was detd. by 3 methods (solvent extn., elemental anal., and hydrolysis) which showed consistent results (20.9,
27.3, and 23.4 mole %, resp., at 240°, 1 hr). An increase in conversion was obsd. at temps. > 240°. The X-ray diffraction diagram of the
product contg. the above Cu salt differed from those of CuO, BzOCu, and (BzO)2Cu.
Source: [Copper benzoate formed in the reaction of benzoic anhydride with excess cupric oxide. Yamauchi, Shinji; Fuji, Shuya. Sch. Sci. Eng.,
Waseda Univ., Tokyo, Japan. Nippon Kagaku Kaishi (1974), (4), 727-31. CODEN: NKAKB8 ISSN: 0369-4577. Journal written in Japanese. CAN
81:3539 AN 1974:403539 CAPLUS (Copyright 2004 ACS on SciFinder (R))]
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ordenblitz
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I have experimented with copper benzoate in an attempt to make blue pyrotechnic whistle composition.
That was a failure but I did find that it was a good fuel in combination with most common pyrotechnic oxidizers.
I made it via:
C7H6O2 + CuCO CU(OH)2 => Cu(C6H5COO)2 + CO2
It couldn't be easier, but since the solubility of C7H6O2 is .029 g/10 ml @ 20° C it takes a few hours for the reaction at room temperature. The
product is fairly insoluble so once through a filter followed by a DH2O rinse and you have reasonably pure copper benzoate.
[Edited on 14-9-2004 by ordenblitz]
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JohnWW
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As an experimental exercise involving benzoic acid and its derivatives such as benzaldehyde, how about making benzoin (not to be confused with gum
benzoin), C6H5-CHOH-CO-C6H5, also known as phenyl-alpha-hydroxybenzyl ketone, or benzoyl benzyl alcohol? I once made some in a stage 2 Chemistry
organic laboratory class, as a creamy powder, by the condensation of benzaldehyde in the presence of KCN.
It is an important intermediate for further organic syntheses, e.g. tetraphenylcyclopentadienone (which I also made, see http://jade6.truman.edu/~patter/organic/patterson/cyclopenta... ) involving oxidation to benzil, C6H5-CO-CO-C6H5. (However, I have been unable to
find out anything about what its dehydration product would be with H2SO4 - it has no H alpha to the -OH, so cannot dehydrate in the normal ways for a
secondary alcohol. A possibility is a dimeric ether which is also an alkene).
John W.
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