A New Efficient Synthesis of p-Nitrocalix[4]arene

A new efficient synthesis of p-nitrocalix[4]arene from calix[4]arene by using nitrogen dioxide is described.The compound is an useful intermediates for the introduction of other functional groups to obtain N containing substituted calix[4]arene.The reaction mechanism is briefly discussed.     

Uncoupled metabolism stimulated by chemical uncoupler and oxic-settling-anaerobic combined process to reduce excess sludge production

The effects of three uncoupled metabolic systems (conventional activated sludge process with the addition of 3,3′,4′,5-tetrachlorosalicylanilide [TCS], oxic-settling-anaerobic [OSA] process modified by insertion of a sludge-holding tank in the sludge return line, and TCS and OSA combined process) on reducing excess sludge production were studied. Compared with the control conventional activated sludge process, the most effective system was the combined process, which could reduce excess sludge production by 46.90%. The 180-d operation results confirmed that TCS is an effective chemical uncoupler in reducing the sludge yield but that it had an adverse effect on substrate removal capability, effluent nitrogen concentration, and sludge settleability. The OSA process decreased excess sludge production by only 26% but had less adverse effect on effluent quality and could improve sludge settleability. The effluent total phosphorous concentration of the three systems was slightly lower than of the control unit. Microbial populations were monitored by both microscopic and molecular biologic analysis method (polymerase chain reaction [PCR]-denaturing gradient gel electrophoresis [DGGE]). The presence of TCS caused metazoans to disappear and decreased the number and activity of protozoa. PCR amplification of 16S rRNA and sequent DGGE analysis found a shift in the diversity of the predominant species. The results imply that OSA combined with the chemical uncoupler process may effectively reduce excess sludge yield and not affect process performance significantly.     

Facile synthesis of 9-（N-amino-4-fluoromethyl-3-pyrrolidinyl）-2- fluoro-6-aminopurine from trans-4-hydroxy-L-proline

A novel and simple procedure for synthesis of azanucleoside by Mitsunobu reaction between N-(p-nitrobenzyloxycarbonyl)- trans-4-hydroxy-D-proline methyl ester obtained from trans-4-hydroxy-L-proline after six-step reaction and 2-fluoro-6-azidopurine is described,and azanucleoside is fluorinated by new fluridizer 2,2-difluoro-1,3-dimethylimidazolidine (DFI).All reactions could be carded out under mild condition.     

Selective dimerization of α-methylstyrene catalyzed by a solid acid

A novel solid acid prepared from concentrated sulfuric, boric and phosphoric acid is a highly selective catalyst for the dimerization of α-methylstyrene at room temperature to generate 4-methyl-2,4-diphenyl-1-pentene.     

A New HPLC Method to Determine Carbonyl Compounds in Air

In this paper,a new HPLC method was established to determine the earbonyl compounds in air.As the absorbent,2,4-dinitrophenylhydrazint(2,4-DNPH)reaeted with earbonyls specifieally,which form the corresponding 2,4-dinitrophenylhydrazones,then analyzed by HPLC.The chromatographic conditions,the recovery rate,stability of samples,reagent blank,sampling efficiency were all studied systematically.The results showed that this established method had high sensitivity and good selectivity compared with other analytical methods,and it can detemine ten earbonyl compounds in air in 26 min simultancously.     

铜基催化剂的结构、物性及其对混合碳四选择加氢反应的催化性能

 用XRD，XPS，SEM和H2－TPR等手段研究了铜基负载型催化剂的结\r\n构和物性及其对混合碳四加氢脱炔的催化性能．结果表明，在负载铜催\r\n化剂中加入一定量的Co可提高催化剂的加氢脱炔活性，而Co含量较少时\r\n加入少量的Ce也能提高催化剂的活性和选择性．Cu和Co之间存在着相互\r\n协同作用，使得活性组分在催化剂表面偏析，CuO在催化剂表面呈非晶\r\n相分散状态，催化剂颗粒粒径变小，催化剂更容易被还原，从而改善了\r\n催化剂的催化性能．     

ADSORPTION OF 2,4-DICHLOROBENZOXYACETIC ACID ONTO HYPERCROSSLINKED RESIN MODIFIED BY PHENOLIC HYDROXYL GROUP (AM-1)

INTRODUCTIONAdsorption has been considered to be the best available technology for removing organics from water in the USSafe Drinking Water Act[1]. Due to many drawbacks of activated carbon[2-7], the most widely used adsorbent,hypercrosslinked polymeric adsorbents developed by Tsyurupa and Davankov[8] have been increasingly viewedas an alternative to activated carbon for selective removal of specific organic substances from contaminatedwater[9-12], and series of researches have been do…     

A simple synthesis of (±)-2,6-dimethylocta-5(<Emphasis Type="Italic">Z</Emphasis>),7-diene-4-ol and its attractant activity for the bark beetle <Emphasis Type="Italic">Ips typographus</Emphasis>

A simple method for the synthesis of (±)-2,6-dimethylocta-5(Z),7-diene-4-ol possessing a high pheromone activity for the bark beetle Ips typographus was developed.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2245–2247, October, 2004.     

A short synthesis of 4-amino-3-hydroxybutyric acid (GABOB) via allyl cyanide

4-Amino-3-hydroxybutyric acid was synthesized from allyl cyanide in four steps in an overall yield of 38%. Ultrasonically promoted epoxidation of allyl cyanide with m-chloroperoxybenzoic acid giving oxiranylacetonitrile was used as a key step.