Xylenol Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
WEISSE BIS GELBE FLüSSIGKEITODER KRISTALLE MIT CHARAKTERISTISCHEM GERUCH.
PHYSIKALISCHE GEFAHREN
Staubexplosion der pulverisierten oder granulierten Substanz in Gemischen mit Luft m?glich.
CHEMISCHE GEFAHREN
Reagiert mit S?ureanhydriden, S?urechloriden, Basenund Oxidationsmitteln.
ARBEITSPLATZGRENZWERTE
TLV nicht festgelegt (ACGIH 2005).
MAK nicht festgelegt (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den K?rper durch Inhalation, über die Haut und durch Verschlucken.
INHALATIONSGEFAHREN
Nur ungenügende Angaben vorhanden über die Geschwindigkeit, mit der eine gesundheitssch?dliche Konzentration in der Luft beim Verdampfen bei 20°C erreicht wird.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Die Substanz ver?tzt die Augen und die Haut. ?tzend beim Verschlucken. Die Substanz reizt die Atemwege (s. Anm.)
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
(S. Anm.)
LECKAGE
Zündquellen entfernen. Ausgelaufene Flüssigkeit in abdichtbaren Beh?ltern sammeln. Verschüttetes Material in abdichtbaren Beh?ltern sammeln. NICHT in die Umwelt gelangen lassen. Pers?nliche Schutzausrüstung: Chemikalienschutzanzug mit umgebungsluftunabh?ngigem Atemschutzger?t.
Chemische Eigenschaften
White, crystalline solid. Only slightly
soluble in water; soluble in most organic solvents
and caustic soda solution. Combustible.
Verwenden
Disinfectants, solvents, pharmaceuticals, insecticides
and fungicides, plasticizers, rubber chemicals,
additives to lubricants and gasolines, manufacture
of polyphenylene oxide (2,6-isomer only),
wetting agents, dyestuffs.
Vorbereitung Methode
Xylenes are obtained mainly (80%) from petroleum reformate streams in the form of "mixed xylenes." A typical composition of this stream is about 18 percent p-xylene, 40 percent m-xylene, 22 percent o-xylene, and 20 percent ethylbenzene. The major chemical uses of xylene, however, require the pure isomers. The purification process involves a number of steps. First the a-xylene is separated from the other aromatics by distillation, with the meta and para isomers going overhead along with the ethylbenzene. p-Xylene can be recovered by either adsorption or crystallization processes. In the adsorption process, the stream is charged to a fixed bed of molecular sieves, and the selectively adsorbed p-xylene is recovered by washing the bed with solvent. Because the demand for p-xylene is far greater than that for m-xylene, the raffinate usually is isomerized to form more ofthe para isomer. Toluene may also be disproportionated to form equivalent amounts of benzene and xylenes without any ethylbenzene. Recently, this TOP process became more favorable. Today, it contributes to 18.5 percent of xylene production.
In 1999, the total demand for the xylenes (12.3 billion lb) was roughly comparable to that for toluene. The volume of 0-, m- and p-xylene were approximately 1.1 , 0.27, and 9.9 billion lb, respectively. The principal uses of the three xylene isomers are the production of terephthalic acid (or di-methyl terephthalate), phthalic anhydride, and isophthalic acid, respectively.
Chemische Reaktivit?t
Reactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Sicherheitsprofil
A poison. When heated
to decomposition it emits acrid smoke and
irritating fumes. See also other xylenol
entries.
Xylenol Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
