91-25-8Relevant articles and documents
Method for synthesizing O-sulfonic acid benzaldehyde under normal pressure
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Paragraph 0025-0049, (2020/03/09)
The invention relates to a method for synthesizing o-sulfonic acid benzaldehyde under normal pressure. The method comprises the following steps: by using o-chlorobenzaldehyde as a raw material and metasulfite as a sulfonating agent, carrying out sulfonation reaction under the catalytic action of tert-butylamine salt or quaternary ammonium salt to generate benzaldehyde-2-sulfonate, and acidifying to obtain the o-benzaldehyde sulfonate. The preparation method is mild in condition, capable of preparing the o-sulfonic acid benzaldehyde at normal pressure and low temperature, few in side reaction,high in yield, simple in post-treatment, high in safety, low in cost, simple to operate and easy to control in industrial production.
Degradation of fluorescent whitening agents in sunlit natural waters
Kramer,Canonica,Hoigne,Kaschig
, p. 2227 - 2234 (2007/10/03)
Stilbene-type fluorescent whitening agents (FWAs), such as the distyryl biphenyl (DSBP) and the diaminostilbene types (DAS 1 and DAS 2), are commonly used in detergents and papers. They are not readily biodegradable, but due to their ability to absorb part of the terrestrial sunlight, they can be photochemically degraded in natural surface waters. Following a fast preceding photoisomerization, the three compounds are degraded by direct photochemical processes yielding mainly aldehydes and alcohols. Their degradation quantum yields are similar, about 10"SUP -4" . Nevertheless, in samples of a eutrophic Swiss lake water, DSBP is photochemically degraded three times faster (t"SUB 1/2" =87 min) in summer noon terrestrial sunlight at 25 degrees C than DAS 1 and DAS 2 (t"SUB 1/2" =278 and 313 min) because of a higher rate of sunlight absorption by the DSBP isomer mixture. All FWAs are degraded faster if the oxygen concentration is increased. Dissolved natural organic material partly inhibits the degradation of DSBP in the reaction with molecular oxygen. The behavior of these compounds illustrates the influence of a preceding isomer equilibrium on degradation rate coefficients. (Authors)
Certain derivatives of particular 3-thiolated cephalosporins
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, (2008/06/13)
Compounds of the formula STR1 wherein A is hydrogen, hydroxy, methyl or methoxy, R1 is hydrogen, sodium or potassium, R2 is carboxyl or an aliphatic, aromatic or heterocyclic radical to which there is also attached a strongly acidic group in the form of its sodium or potassium salt, and R3 is 1,2,3-triazol-5-yl, such group being unsubstituted or substituted with one or two lower alkyl groups of one to four carbon atoms are prepared by reacting the appropriate aldehyde with the corresponding amphoteric cephalosporin. A preferred product has the structure STR2