Graphite Oxide and Aromatic Amines: Size Matters

Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molecules prefer to covalently connect to the graphene oxide matrix via chemical grafting, while napthalene amine molecules bind with the graphene oxide surface through π–π interactions. The presence of intercalated aromatic molecules between the graphene oxide layers is demonstrated by X‐ray diffraction, while the type of interaction between graphene oxide and polycyclic organic molecules is elucidated by X‐ray photoelectron spectroscopy. Combined quantum mechanical and molecular mechanical calculations describe the intercalation mechanism and the aniline grafting, rationalizing the experimental data. The present work opens new perspectives for the interaction of various aromatic molecules with graphite oxide and the so‐called “intercalation chemistry”.     

Content of Vasoactive Amines in Sremski Kulen and Sremska Kobasica Traditional Dry Fermented Sausages From Vojvodina

The aim of this paper was to determine the content of vasoactive biogenic amines in Sremski kulen and Sremska kobasica and to estimate hygienic conditions and good manufacturing practice (GMP) according to proposed criteria. Formation of dansyl chloride derivatizated vasoactive amines were determined using HPLC–DAD. Tryptamine (47.6; 34.2 mg/kg), histamine (16.1; 6.42 mg/kg) and tyramine (95.1; 45.2 mg/kg) were detected in both investigated type of traditional dry fermented sausages while phenylethylamine was not detected. Total content of vasoactive amines did not exceed the sum (200 mg/kg) proposed as a possible indicator of hygienic conditions and GMP in sausage production.     

Long-chain fatty ammonium quaternaries in papermaking

A series of long-chain quaternary ammonium halogen esters (UKK-chemicals), quaternary dimethyl tallow epoxypropyl ammonium halogens (EPK1), quaternary ditallow methyl epoxypropyl ammonium halogens (EPK2), and EPK2 oligomers (EPK2P) were synthesized. At acidic, neutral, or slightly basic conditions, EPK1-, EPK2-, EPK2P-, and UKK-chemicals operate as cationic chemicals. They can be used, for example, as stock sizings, surface sizings, or fixatives. Stock sizing, surface sizing, and fixative experiments indicate that EPK1-, EPK2-, EPK2P-, and UKK-chemicals function at least as well as or better than the corresponding synthetic chemicals used in papermaking.     

Electrochemical behaviour of phenylethanolamine at gold in aqueous solution

The electrooxidation of phenylethanolamine (2-amino-1-phenylethanol) at a gold electrode in alkaline electrolyte has been studied. Measurement of the differential capacitance of the electric double layer versus the electrode potential has shown that the adsorption of phenylethanolamine at the gold-solution interface plays a significant role in the oxidation mechanism. The effect of amine concentration, electrolyte pH and potential scan rate on the electrooxidation is analysed.     

Effects of different cooking methods on the formation of food mutagens in meat

Hamburgers and chicken fillets were cooked in convection ovens, deep‐fried or contact fried and analysed for mutagenic activity using the Ames test. For the three different convection ovens, the cooking parameters studied included the presence of steam, air velocity, air temperature and holding time. For deep‐frying and contact frying, the cooking parameters included cooking temperature and cooking time. In cooked hamburgers, mutagenic activity was only detected in those that had been deep‐fried. In chicken fillets, mutagenic activity was detected in samples prepared with all cooking methods, being highest in the deep‐fried samples. Factorial analysis indicated that heat transfer was the most important factor affecting mutagenic activity. High temperature and high air velocity in the convection ovens enhanced mutagenic activity. The presence of steam reduced the mutagenic activity, except when high temperature was used in combination with high air velocity. In chicken fillets, high mutagenic activity correlated to high weight loss during cooking. Pan‐fried chicken fillets were analysed using high performance liquid chromatography (HPLC) and the mutagenic/carcinogenic heterocyclic amines 2‐amino‐3,8‐dimethylimidazo[4,5‐f ]‐quinoxaline (MeIQx), 2‐amino‐1‐methyl‐6‐phenylimidazo‐[4,5‐b]‐pyridine (PhIP) and the co‐mutagenic heterocyclic amine Norharman (9H‐pyrido[3,4‐b]‐indole) were identified. The HPLC fractions were tested for mutagenic activity and, apart from the mutagenic fractions corresponding to MeIQx and PhIP, several mutagenic fractions were detected that did not correspond to known heterocyclic amines.     

Alaska Pollock (Theragra chalcogramma) Mince and Surimi as Partial Meat Substitutes in Frankfurters: N-Nitrosodimethylamine Formation

Studies were conducted to determine the feasibility of using 3 forms of Alaska pollock (AP) as a partial substitute for meat in a nitrite-cured product. The effect of several pre- and post-processing storage conditions on N-nitrosodimethylamine (NDMA) were studied in frankfurters substituted with 15 and 50% unwashed and washed mince and surimi. In franks made with unwashed mince, frozen stored prior to processing, NDMA increased during frozen storage; little change was observed in franks containing washed mince and surimi. Refrigerated storage of franks generally showed a decrease in NDMA with all 3 forms of fish. Overall, the use of washed mince and surimi at the 15% substitution level gave mean values less than 2 ppb NDMA, even after boiling. The results indicate that 50% unwashed AP mince should not be used as a partial substitute for meat in frankfurters.     

Synthesis of tertiary poly(amido-amine)s with amido- and amino-groups randomly arranged along the macromolecular chain

A new synthesis of poly(amido-amine)s from bis (secondary amine)s and acryloyl chloride has been studied, leading to polymers in which the amido- and amino-groups are randomly arranged along the macromolecular chain. A poly(amido-amine) based on piperazine, chosen as the mother compound, has been fully characterized by ¹³C n.m.r. as well as by identification and quantitative evaluation of its hydrolysis products.     

8种新型7胺-基取代的1,4二-氢-3H-2,3苯-并噁嗪-3甲-酸乙酯衍生物的合成

1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯经过硝化、还原和重氮化溴代得到了7溴--1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯(C)。以Pd(OAc)2/R(+)B INAP(2,2′-二苯膦-1,1′-联萘)为催化体系,C与苯胺、N-甲基苯胺、对氟苯胺、对乙氧基苯胺、环己胺、吗啡、四氢吡咯及六氢吡啶等8种有机胺类化合物(Am ine1~8),在氮气保护下,以碳酸铯为碱于干燥的甲苯中100℃反应16~24 h,生成了相应的8种新的7胺-基取代的1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯类化合物(D1~8),反应收率分别为83%、85%、71%、90%、72%、63%、75%和83%。通过1HNMR、质谱和元素分析对这些化合物的结构进行了表征。     

羰基化法合成氨基甲酸酯催化剂的研究进展

对氧化羰基化法、还原羰基化法及氧化还原羰基化法3种羰基化合成氨基甲酸酯方法中催化剂的研究进展进行了综述,其中着重讨论了各种配体及助剂对催化剂活性的影响。指出今后的研究应集中在寻找高效、价廉及可重复使用的催化体系或对高效的均相催化体系进行负载化以及研究多相催化体系的催化机理。