| 摘要 |
<p>#CMT# #/CMT# Lightening color of polyol ester, comprises: reacting polyol with linear or branched aliphatic monocarboxylic acid having 3-20 carbon atoms; subsequently reprocessing the reaction mixture without using adsorbent material; treating the reaction product with ozone or ozone containing gases with an amount of 0.01-5 g of ozone per liter of polyol ester, after separating the unreacted starting compounds; carrying out steam treatment immediately and subsequently without further intermediate steps; and drying the remaining polyol ester. #CMT#USE : #/CMT# The method is useful for: lightening the color of polyol esters; and producing triethylene glycol di-2-ethylhexanoate, tetraethylene glycol di-n-heptanoate, triethylene glycol di-2-ethyl butyrate or triethylene glycol di-n-heptanoate, or tetraethylene glycol di-2-ethylhexanoate (all claimed). #CMT#ADVANTAGE : #/CMT# The method: does not make use of adsorbent materials during reprocessing and thus avoids additional filtration steps and loss of product in the filtering device. The light colored polyol ester obtained by the method: exhibits extremely low peroxide content and thus exhibits high quality; and is self-stable for a longer storage period. #CMT#INORGANIC CHEMISTRY : #/CMT# Preferred Method: The treatment of reaction product with ozone or ozone containing gas is carried out at -30 to 130[deg] C, preferably 30-80[deg] C. The amount of ozone added is 0.1-5 g of ozone per hour and per liter of polyol ester, preferably 0.2-0.9 g of ozone per hour and per liter of polyol ester. The steam treatment is carried out at a temperature of 100-250[deg] C, preferably 170-200[deg] C. The gaseous steam discharged during the steam treatment is contacted with noble metals of group 9-11 of the periodic system of the elements. The steam discharged during the steam treatment is condensed first and the condensed liquid distillate is contacted with the noble metals. The noble metals are fixedly arranged or applied on a carrier. Preferred Components: The amount of ozone per liter of polyol ester is 0.2-0.8 g. The ozone containing gas comprises a gas mixture of ozone with air, oxygen, nitrogen, carbon dioxide or noble gas. The concentration of ozone in the gas mixture amounts to 2-200 g of ozone/m 3>, preferably 10-100 g of ozone/m 3>. The carrier comprises silicon dioxide, aluminum oxide, activated carbon, titanium dioxide or zirconium dioxide. The noble metals are arranged in the form of fabric, net, gauze, wire, clew or sponge. The noble metals comprise palladium or platinum. #CMT#ORGANIC CHEMISTRY : #/CMT# Preferred Method: The polyol ester is dried at a temperature of 80-250[deg] C, preferably 100-180[deg] C and at a pressure of 0.2-500 hPa, preferably 1-20 hPa. The remaining polyol ester is dried immediately and subsequently after the steam treatment without further intermediate steps. Preferred Components: The polyol is of formula (R(OH) n) or (H-(-O-(-CR 1>R 2>-) m-) o-OH). The polyol comprises: 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 2,2-dimethylol butane, trimethylolethane, trimethylolpropane, trimethylol butane, 2,2,4-trimethylpentane-1,3-diol, 1,2-hexanediol, 1,6-hexanediol, pentaerythritol, ethylene glycol or 3(4),8(9)-dihydroxymethyltricyclo[5.2.1.0(2,6)]decane; or di-trimethylolpropane, dipentaerythritol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol or tetrapropylene glycol. The aliphatic monocarboxylic acid comprises propionic acid, n-butyric acid, isobutyric acid, n-pentanoic acid, 2-methyl butyric acid, 3-methylbutyric acid, 2-methylpentanoic acid, n-hexanoic acid, 2-ethylbutyric acid, n-heptanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, n-nonanoic acid, 2-methyloctanoic acid, isononanoic acid, 3,5,5-trimethylhexanoic acid or 2-propylheptanoic acid. R : 2-20C, preferably 2-10C (cyclo)aliphatic hydrocarbon; n : 2-8, preferably 2-6; R 1>, R 2> : H, 1-5C alkyl, preferably methyl, ethyl or propyl, or 1-5C hydroxyalkyl, preferably hydroxymethyl; m : 1-10, preferably 1-4; and o : 2-15, preferably 2-5. #CMT#EXAMPLE : #/CMT# Triethylene glycol and 2-ethylhexanoic acid (2.6 moles) were esterified without using the catalyst and without adding entraining agent to obtain crude triethylene glycol di-2-ethylhexanoate with a color number of 89 Hazen units. Then the reprocessing of the crude ester was carried out in a heated 2-liter four-necked flask. Then ozone containing oxygen stream (with an ozone concentration of 21 g of ozone/m 3>of oxygen) was conducted into crude triethylene glycol di-2-ethylhexanoate at a rate of 0.025 m 3>/hour and at 70[deg] C for 0.5 hours with vigorous stirring. Then the crude triethylene glycol di-2-ethylhexanoate was subjected to steam distillation at 180[deg] C for 1 hour in a distillation apparatus, where a platinum net was arranged in the distillation column, over which the peroxide-loaded steam was conducted. Then the distillate was dried at a pressure of 10 hPa and at a temperature of 140[deg] C for 0.5 hours to obtain light colored triethylene glycol di-2-ethylhexanoate having a color number of 16 Hazen units.</p> |
