Organikum (Wonderful Personality) 07-05-04 07:58 No 517569				Cumene by H2SO4 catalyzed Friedel-Crafts reaction (Rated as: good read)
						For up to now I thought the FC reactions for producing cumene would call for AlCl3 or equal catalyst I was glad to find the following prepartion in the "Gattermann, Praxis des Organischen Chemikers". I decided to translate it for the HIVE community. It should be as valid as Vogel`s preparations. "... Cumol 400 ml 80proz. Schwefelsäure, ..... , werden in einem 1 liter Kolben mit Rückflußkühler, mechanischem Rührer und Tropftrichter, in einem Ölbad auf 65°C (Badtemperatur) erwärmt. Bei dieser Temperatur läßt man unter starkem Rühren (wichtig, da  Zweiphasenreaktion)  innerhalb von 2 h die  Mischung  aus 38 ml (30 g, 0,50 mol) Isopropylalkohol und  89,0 ml (78,0 g, 1,00 mol) thiophenfreiem  Benzol  zutropfen, rührt noch weitere 2 h bei 65°C, läßt abkühlen und gießt in einen 1-I-Schütteltrichter. Man wäscht die obere Schicht mit 50 ml Wasser, 100 ml 2N  Natriumcarbonat-Lösung sowie  2mal mit je 50 ml Wasser und trocknet über Natriumsulfat. ....  Das Reaktionsprodukt wird über eine etwa 20cm lange Kleinfüllkörperkolonne oder eine entsprechende Vigreux-Kolonne fraktionierend destilliert. Nach einem Vorlauf von Ether und Benzol und einer geringen Zwischenfraktion geht Cumol bei 149-152°C (Hauptmenge bei 151°C) über. Ausbeute 38-39 g (63-65%). ...." Translation: (text in italics added by me) Cumene 400 ml H2SO4 of 80% strength are put into a 1000 ml flask which is placed on an oilbath (waterbath will suffice) and equipped with a reflux condensor a mechanical stirrer and an addition funnel. This is heated to 65°C (temp. of the bath). At this temperature are under strong stirring (important as two-phase reaction) added a mixture of 38 ml (30 g, 0,50 mol) IPA and 89,0 ml 78,0 g, 1,00 mol) of benzene free from thiophene. Stirring is continued for 2 more hours at 65°C. Then the mixture is let cool down and poured into a 1000 ml seperation funnel. The upper layer is washed with 50 ml water, 100ml 2N sodiumcarbonate solution and again two times with 50ml water and  obviously the lower layer is removed before these washings dried with NaSO4.  The reaction product is fractionated using a short (20cm) column. Between 149°C and 152°C cumene is retrieved (main part comes over at 151°C). Yields: 38-39 g (63-65%). I hope somebody will find this helpful. ORG xyz
		GC_MS (Hive Addict) 07-06-04 04:03 No 517743				cuminic aldehyde
						If you are interested in cuminic aldehyde, you may be interested in reading Patent US2158518. It describes a one pot synthesis of cuminic aldehyde from benzene, aluminium chloride, CuCl, isopropyl chloride and bubbling in CO gas. The end product is not pure, but a raw purification should be possible by first isolating the bisulfite adduct, followed by a fractionated distillation to isolate fairly pure cuminic aldehyde. Cuminic aldehyde is a very pleasantly odoring substance and used as precursor for cyclamenaldehyde (sowbread), something every bee should have synthesized at least once in his/her lifetime. Aztecunnilingus Maximus