Reference

Prevention of corrosion caused by naphthenic acids in refineries

Prevention of corrosion caused by naphthenic acids in refineries. Humblot, Francis (Atofina, Fr.). Fr. Demande FR 2857372 A1 14 Jan 2005, 11 pp.Chemicals with cas numbers 2365-48-2 and 25103-09-7 also play role. (French). (France). CODEN: FRXXBL. CLASS: ICM: C10G075-02. ICS: C10G007-10. APPLICATION: FR 2003-8250 7 Jul 2003. DOCUMENT TYPE: Patent CA Section: 51 (Fossil Fuels, Derivatives, and Related Products) Section cross-reference(s): 56 Corrosion of metal walls in refinery units by naphthenic acids is prevented by injection of a compd. having a formula of HS-B-COOR (I) (where B = a bivalent satd. hydrocarbon radical contg. 1-18 C atoms (preferably 1-4); R = H, alkali metal, alk.-earth metal, NH4, or an alkyl radical (linear or branched), cycloalkyl, aryl, alkylaryl, or arylalkyl contg. 1-18 C atoms (preferably 1-10)) into a hydrocarbon stream. Preferably, I is thioglycolic acid or its esters. Amt. of I addn. is 10-5,000 wt. ppm (as S), preferably 50-500 ppm. The treatment is carried out at 200-450° (preferably at 250-350°). The treatment is suitable for crude oil, a residue of atm. distn., a residue and a distillate of vacuum distn., and gas oil fractions. .

Amino Acids, 2

Amino Acids, 2. N-Acetyl a,b-didehydro a-amino acid esters from a-azidocarboxylic acid esters by nitrogen elimination with rhenium catalysts. Effenberger, Franz; Beisswenger, Thomas (Inst. Org. Chem., Univ. Stuttgart, Stuttgart D-7000/80, Fed. Rep.In this article, certain chemicals are used. Some of their cas registry numbers are 2365-48-2 and 90237-73-3 Ger.). Chem. Ber., 117(4), 1497-512 (German) 1984. CODEN: CHBEAM. ISSN: 0009-2940. DOCUMENT TYPE: Journal CA Section: 34 (Amino Acids, Peptides, and Proteins) a-Azido carboxylic acid esters RR1CHCH(N3)CO2R2 (R = H, R1 = H, Pr, Ph, SCH2CO2Me, OMe, CO2Me, SPh, R2 = Me; R-R2 = Me; R = OH, R1 = Me, R2 = Et) were treated with Ac2O in the presence of Re2S7 to give the N-acetylated dehydroamino acids RR1C:C(NHAc)CO2R2 (I) and/or RR1C:C(NAc2)CO2R2. I were formed exclusively when H2O was added before work up. .