|0.05 mg; 0.9 mg; 0.18 mg; 1.4 mg; 1.2 mg; 0.67 mg; 0.28 mg; 0.85 mg; 0.14 mg
||With sodium silicate solution; CuN2O6; In water; at 80℃; for 24h;pH 7.57;
||General procedure: To model the chemical environment on the outer side of thetubular structures, NH2CHO (200 muL) was mixed with thesodium silicate solution (2.0 mL) in the presence of preformedMSH [ZnCl2, FeCl2·4H2O, CuCl2·2H2O, Fe2(SO4)3·9H2O,and MgSO4] (2.0% w/w) at 80 C for 24 h. In two selectedcases [FeCl2 and Fe2(SO4)3·9H2O], NH2CHO (200 muL) wasmixed with the sodium silicate solution (2.0 mL) in the presence of selected growing MSH (starting from 2.0% w/w ofthe corresponding salt?s pellet) at 80 C for 24 h. For the innerenvironment, NH2CHO (200 muL) was mixed with distilledwater (2.0 mL) in the presence of selected MSH (2.0% w/w) at80 C for 24 h. The reaction of NH2CHO (10% v/v) with thesodium silicate solution (pH 12) without MSH membranes wasalso analyzed under similar experimental conditions. Theproducts were analyzed by gas chromatography associatedwith mass spectrometry (GC-MS) after treatment with N,Nbis-trimethylsilyl trifluoroacetamide in pyridine (620 muL) at 60C for 4 h in the presence of betulinol (CAS Registry Number473-98-3) as the internal standard (0.2 mg). Mass spectrometrywas performed by the following program: injection temperature280 C, detector temperature 280 C, gradient 100 C for 2min, and 10 C/min for 60 min. To identify the structure of theproducts, two strategies were followed. First, the spectra werecompared with commercially available electron mass spectrumlibraries such as NIST (Fison, Manchester, U.K.). Second, GCMSanalysis was repeated with standard compounds. Allproducts have been recognized with a similarity index (SI)greater than 98% compared to that of the reference standards.The analysis was limited to products of ?1 ng/mL, and theyield was calculated as micrograms of product per startingformamide. For further experimental details, see the SupportingInformation.