Chemistry of marine resources——XVI. A new potassium reagent and its enrichment behaviour for potassium ion in seawater

-This paper first presents a new potassium reagent and efficient enrichment agent for direct recovery of potassium from seawater, i. e. , 1, 2, 4, 5-tetrahydroxybenzen -O, O' , O', O'''- tetraacetic acid (TTAH4). The synthetic method of TTAH4, its enrichment behaviour for potassium ion in low concentration solution and seawater, and the chemical structure of its corresponding potassium salt have been investigated. A mechanism which caused the uptake of potassium ion is suggested. Elementary analysis and IR-spectrum determination of the potassium salt proved correct evidence for a polynuclear complex, i. e. , (TTAH3K)n. Thus, the mechanism which caused the uptake of potassium ion may be interpreted in terms of the formation of polynuclear chains as a continual sandwich type coordination complex.

DCHA AS A NEW REAGENT FOR THE ESTERIFICATION OF OBSTINATED AMINO ACIDS BY THE MERRIFIELD'S RESIN

The obstinated amino acid,Boc-Asn(or Boc-Gln),was directly anchored onto the Merrifield's resin using DCHA as the base in present reaction.The yield(71.88%)of Boc-Asn-OCH_2-resin was much better than those(0-33.5%)using Cs_2CO_3,KOH,KF.DEA and TEA as the base.which are efficient reagents for other amino acids in the same reaction.

A New Reagent for the Reduction of Aromatic Nitro Compounds

Aromatic nitro compounds were reduced to the corresponding anilines by refluxing with potassium selenated borohydride (KBH2Se3) prepared from potassium borohydride and selenium in refluxed formamide.

MECHANISM OF ELECTROCHEMILUMINESCENCE OF THE NEW REAGENT 6-(2-HYDROXY-DIETHYLAMINOPHENYLAZO)-2, 3-DIHYDRO-1, 4-PHTHALAZINE-1, 4-DIONE CATALYZED BY SILVER (Ⅰ)

The electrochemi luminescence <ecl> of a new reagent 6-<2-hydroxy-4-diethylaminophenylazo>-2, 3-dihydro-1, 4-phthatazine-1, 4-dione <HDEA> in basic aqueous solution was studied. Trace amount of silver showed significant effect on the efficiency of light emission of HDEA during a positive trigonometrical wave pulse was exerted on the electrodes In the present paper, the ecl spectra of HDEA have been measured. λ_(max) is 410 nm. The reaction of HDEA chemiluminescence and the circular voltammetry, ultraviolet-visible spectrometry for the system have been investigated. The possible mechanism of the ecl of HDEA-KCL-KOH-Ag(I) system has been proposed.

SYNTHESIS AND CHARACTERIZATION OF 2-(2-HYDROXY-3,5-DINITROPHENYLAZO)-7-(4-CHLORO-PHOSPHONPHENYLAZO)-1, 8-DIHYDROXY-NAPHTHALENE-3, 6-DISULF-ONIC ACID (CPAP) AS NEW REAGENT FOR DETERMINATION OF TOTAL PARE EARTHS

This paper reports the synthesis and general properties of the new reagent CPFP. Its dissociation constants have been determined. The characterization in determinating total RE with CPAP reagent has been investigated in detail. Analytic data for synthetic sample are satisfactory.

A NEW SULFINATODEHALOGENATION REAGENT:THIOUREA DIOXIDE

The reaction of perfluoroalkyliodides,perfluoroalkylbromide,1,1, 1-trifluoro-2,2,2-trichloro-ethane,and carbon tetrachloride with thiourea dioxide in aqueous acetonitrile solution gave the corresponding sulfinate in good yield.

Separation of sulfide lead-zinc-silver ore under low alkalinity condition

A complex lead-zinc-silver sulfide ore containing 2.98% Pb, 6.49% Zn and 116.32×10^-4 % Ag （mass fraction） from Yunnan Province, China, was subjected to this work. Research on mineral processing was conducted according to the properties of the lead-zinc-silver ore. Under low alkalinity condition, the lead minerals are successfully separated from the zinc minerals with new reagent YZN as zinc depressant, new reagent BPB as lead collector, CuSO4 as zinc activator and ethyl xanthate as zinc collector. The associated silver is mostly concentrated to the lead concentrate. With the process utilized in this work, a lead concentrate of 51.90% Pb with a recovery of 82.34% and a zinc concentrate of 56.96% Zn with a recovery of 81.98% are produced. The silver recovery in the lead concentrate is 80.61%. Interactions of flotation reagents with minerals were investigated, of which the results indicate that the presence of proper amount of Na2S can precipitate Pb^2＋ and has a sulfidation on oxidized lead minerals. The results also show that NazCO3 and YZN used together as combined depressants for sphalerite can signally improve the depressing effect of new reagent YZN on sphalerite.

Asymmetric trifluoromethoxylation with new reagent

Subject Code:B02 With the support by the National Natural Science Foundation of China,the research group led by Prof.Tang Pingping(汤平平)from Nankai University reported the asymmetric and direct trifluoromethoxylation with trifluoromethyl aryl sulfonate(TFMS)as a new

Studies on sulfinatodehalogenationⅩⅫ.A new sulfinatodehalogenation reagent system:NaHSO3/K3[Fe(CN)6]

Sodium dithionite-initiated addition of R_FI(1)[R_F.=1a,Cl(CF_2)_4;1b,Cl(CF_2)_6;1c, Cl(CF_2)_6;1d,n-C_6F_(13);1e,n-C_8F_(17)]to the properly protected glucose derivatives 2,9,12 and 15 gave polyfluoroalkylated glucose derivatives 7,11,14 and 17 respectively in good yields after reduction and deprotection.These compounds are strongly surface active.

A new reagent pair sodium percarbonateacetic anhydride for epoxidation of olefins

A new convenient method for epoxidation of olefins by sodium percarbonate-acetic anhydride is reported.It is found that the epoxides in 60—80% yields can be obtained in 18—24 h without ultrasonication.However,higher yields(some nearly quantitative)can be reached only within 1—3 h under ultrasonication.A comparison between the ultrasonicated epoxidations by use of sodium percarbonate and sodium perborate is also made.The experimental results have revealed that ultrasonication plays a main role in accelerating the interaction of both sodium percarbonate and sodium perborate with acetic anhydride,but it does not alter the mechanism of these two epoxidations.

Design, Synthesis and Application of a Robust d_(3)-Methyithiolating Reagent

A deuterated methylthiolating reagent with a broad spectrum,designated as DMTp,has been ingeniously formulated.This new reagent can be produced with high efficiency through the simple combination of commercially available methyl 3-thiopropanoate and CD_(3)l.This novel SCD_(3) reagent exhibits excellent reactivity with electrophiles such as alkyl iodides,benzyl chlorides,aryl halides(l,Br)and aryl triflates,resulting in high levels of deuterium content(99%D).Representative deuterated methylthiolated biomolecules,such as Sulfoxaflor,havebeen synthesizedforuse in pharmaceutical discoveryand development.