天然胶乳氯化反应历程研究

采用红外光谱和化学分析方法 ,对天然胶乳的氯化反应进行了跟踪分析 ,其反应历程应与溶液法工艺氯化历程相似 :1)取代氯化和环化 ,由Cl+ 进攻天然橡胶分子 ,产生的最初取代 ,伴随环化 ,导致二个异戊二烯单元中一个CC双键转化为C—C单键 ;2 )加成 消除 ,伴随C—C基团的转移 ;3)纯粹取代 .但胶乳法在第三步“纯粹取代”的同时 ,生成了一定量的叔碳C—Cl键 ;红外光谱还跟踪纪录了胶乳法CNR中ClCCO和ClC—COOH基团的生成 ,此二点为胶乳法CNR和溶液法CNR结构上最大的不同之处 ,也是导致胶乳法CNR稳定性差于溶液法CNR的主要因素 .从1 3C NMR对胶乳法CNR分析得出样品中含有的伯、仲、叔碳C—Cl键的比例 ,结合IR光谱和裂解色谱 质谱分析 ,得出胶乳法CNR氯化反应的历程 ,氯原子的取代与加成顺序 ;并由结果分析可知 ,胶乳法CNR的结构不如溶液法CNR规整 ,其主要原因为氯化起始阶段有HOCl加成、生成了较多的叔碳C—Cl键以及氯化后期有一定量的ClCCO和ClC—COOH基团生成 .此外 ,还得出结论 :胶乳法制备CNR的氯化反应在所有的NR分子上均匀发生 .     

Structure of chlorinated poly(vinyl chloride). X. Conclusions on the chlorination mechanism

The chlorination of poly(vinyl chloride) (PVC) was investigated by using deuterated polymeric models of PVC, viz., α-deuterated PVC (α-d-PVC) and β,β-dideuterated PVC (β,β-d₂-PVC). The chlorinated samples of PVC, α-d-PVC, and β,β-d₂-PVC were examined by combining infrared (IR), ¹H-NMR, ¹³C-NMR, and mass spectroscopy. The results obtained were used in a study of the reaction mechanism of PVC chlorination. The selectivity of chlorination and the extent of the substitution and elimination-addition mechanism of chlorination are discussed with respect to the degree of chlorination and chlorination conditions.     

Heterogeneous reactions of polyethylene. II. Distortion of crystallites due to chlorination

The effect of heterogeneous chlorination of high-density polyethylene on its crystalline regions was investigated by NMR, x-ray diffraction, differential scanning calorimetry, and infrared spectroscopy. Crystallites remained inaccessible to attack by chlorine, even after extensive chlorination, however, their perfection was affected by extensive chlorination of the adjacent amorphous regions.     

固相氯化法合成氯化聚乙烯的红外光谱研究

本文研究在不同条件固相氯化聚乙烯(CPE)的红外光谱,探讨了一步和两步氯化合成的CPE的结构差别,着重讨论了两步氯化的CPE结构特点。从观察表征结晶结构和—(CH_2)_n—链段氯分布的特征频率变化表明,低温固相氯化主要发生在无定形区,并且在CPE中形成高氯化和低氯化链段(或未氯化)的嵌段结构。在两步固相氯化时,晶区受到较大程度的破坏,氯化作用已不局限在无定形区,其结晶结构的破坏主要同第二步氯化程度有关,即使CPE氯含量相同,若前后两步氯化程度不同,结构有很大差异。     

A Convenient Method for Chlorination in Allylic Position

A convenient method for the chlorination in allylic position was developed by using the aqueous solution of sodium hypochlorite(2%-5% active chlorine) and an acid as chlorination reagent in a diphase system.The method has the advantage of cheap reagents, mild reaction conditions and good yields. The quantity and the feeding rate of the chlorination reagent can be controlled easily. The method is particularly suitable for the chlorination in laboratories.     

电石渣在煅烧/氯化反应中的HCl脱除特性研究

采用钙基废弃物———电石渣煅烧后脱除HCl。在煅烧/氯化反应器上研究脱氯反应温度、HCl体积分数、颗粒粒径和煅烧温度对电石渣脱氯性能的影响。结果表明,电石渣在700℃时取得最高氯化转化率;脱氯反应温度高于650℃后,电石渣氯化转化率均高于石灰石,电石渣高温脱氯更有优势。电石渣氯化转化率随反应气氛中HCl体积分数提高呈线性增长。随电石渣颗粒粒径增大,氯化转化率缓慢降低。高于900℃的煅烧温度不利于电石渣脱除HCl。煅烧后电石渣分布在2~10 nm的孔隙较多,氯化后分布在此孔径范围内的孔容和孔面积分别降低了56.2%和62.2%,2~10 nm孔隙是煅烧后电石渣吸收HCl的主要区域。     

氯化反应合成聚甲基氯硅烷的研究

以四氯化碳为氯化剂。利用聚甲基硅烷(PMS)Si-H键的反应活性。在室温条件下即可通过氯化反应制备PCMS。研究发现。随着反应时间的增长。硅氢反应程度增大,所得PCMS的氯含量相应增大。但分子量分布变化不大。PCMS仍保持其离域结构;同时。PMS分子的支化程度越高,氯化反应的速度越快。PCMS的结构以^1H-NMR和^29Si CP MAS-NMR等手段予以表征和确认。初步讨论认为反应属于自由基反应,四氯化碳对Si-H具有较高的选择性。     

Studies on Kinetics of Chlorination Reaction of Polyethylene

Through kinetic method, the reaction mechanism and the rate equations of chlorination of polyethylene are suggested in this paper. The rate of chlorination is second order with respect to the concentration of methylene remained and chlorine, respectively. Apparent changes in crystallinity during chlorination processes were determinated by differential scanning calorimetry(DSC). The mathematical model relating crystallinety with kinetic parameters and function of sequence length distribution are derived.     

2—氧代—3,5,7—三氯吲哚丁酸乙酯的结构分析

为研究吲哚丁酸类氯化物的生理活性，对吲哚丁酸进行酯化、氯化和水解。用高分辨率的质子磁共振谱、质谱和红外光谱、元素分析确证了吲哚丁酸乙酯氯化产物为化合物２－氧代－３，５，７－三氯吲哚丁酸乙酯，该化合物未见文献报道，提出了其生成的可能机理。     

Chlorination and characterization of natural rubber and its adhesion to nitrile rubber

Chlorinated natural rubber (CNR) vulcanized sheets were prepared by immersing the NR sheets in sodium hypochlorite solution for various chlorination times ranging from 0 to 30 min. The degree of chlorination as indicated by X-ray Absorption Near-Edge Spectroscopy (XANES) implied that the chlorine content increases with the chlorination time from 0 to 10 min then levels off. Atomic Force Microscopy (AFM) showed an evolution of the surface roughness and stiffness. These two properties increased gradually with chlorination time. The bond strength between CNR and nitrile rubber (NBR) also increased gradually. The data showed cohesive failure beginning at 1 min and extending throughout the 30 min of the study. The maximum peel strength was found at 1 min of chlorination time and decreased afterwards. The decrease in peel strength was caused by the increase in surface stiffness of NR that acted as weak boundary layer. The surface stiffness governed the peel strength between NR and NBR.     

Preparation of 1,1,3,-Tetraisopropyl-l,3-Dichlorodisiloxane and Triisopropylchlorosilane

A facile, hydrochloric acid-free chlorination of silanes was developed. This allows for the elimination of siloxane bond cleavage and chlorination of carbon-hydrogen bonds during the chlorination of the Si-H bond.     

氯化聚乙烯弹性体的固相法合成

讨论了以固相法合成氯化聚乙烯（ＣＰＥ）弹性体的过程．实验结果表明，以固相氯化反应所得的ＣＰＥ，其大分子链上Ｃｌ取代基的分布比水相悬浮法更均匀．氯化过程的温度直接影响氯化速度及分子结构，如残留结晶、氯分布等．而聚乙烯颗粒表面与内部的氯化程度取决于氯化速度．大分子链上Ｃｌ取代基对邻近基团的氯化起阻碍作用     

Preparation,Properties and Reactions of Polychloroamine Derivatives

Highly chlorinated amine derivatives can be prepared by the high-temperature chlorination of amines and amine derivatives. Essential for the success of this reaction is an adequate temperature control suited to the constitution of the amines. In many cases the chlorination products achieve stability by cleavage reactions with formation of the imidic acid chloride or isocyanide dichloride grouping. Cyclic compounds are formed under special conditions. The chlorination process described can be used to obtain e.g. polychloroaryl and polychloroalkyl isocyanide dichlorides, polychloroaryl and polychloroalkyl imidic acid chlorides, and polychloroheterocyclic compounds.     

成黄成色剂2-十六烷氧基苯甲酰乙酰基-(2'-氯-5'-苯胺磺酰基)苯胺氯化产物的鉴识

Much work has been recorded in the literature concerning chlorination of photographic couplers. However, no detailed report can be found with the coupler of the structure 1. In this paper, the chlorination of 1 using SO2Cl2 in CHCl3 was shown to give the chlorination product 2. UV, IR, 1H NMR and MS of the chlorination product are compared with that of 1, and with those reported in the literature for benzoylacetanilide. Thermolysis of 2 gives a liquid fraction, HPLC shows one peak, which was identifield by 1H NMR and MS to be o-CH3COC6H4OCH2CHClC14H29. Elemental analyses as well as MS of its 2, 4-dinitrophenylhydrazone agree well with the structure assigned.     

Interactions during the chlorination of a copper–zinc alloy

In this paper several aspects involved in the chlorination of a Zn 48% wt.–Cu alloy between 250 and 500 °C are investigated. The starting temperature for the chlorination of the alloy is determined, which is different from those of pure metals. Analysis of the chlorination thermogravimetric curves and reaction products reveal that there are interactions between reactants and products during the reaction, and that volatilization of ZnCl₂ is diminished during the alloy chlorination. Metallic copper is detected at intermediate stages of the chlorination, and this element, which is not present in the initial sample, appears during the chlorination reaction. An oxidation–reduction type reaction between copper chlorides and metallic zinc is proposed to explain the behaviour observed. The occurrence of this reaction at room temperature was confirmed in separate experiments. At the beginning of the reaction, formation of zinc oxichloride was detected that is being formed from the zinc oxide layer that covers the alloy surface. According to the results obtained, a reaction mechanism is presented for the alloy chlorination.     

Low-temperature radical polymerization of acrylamide in ethanol and glycerol under the action of molecular chlorine

It is shown by means of calorimetry, IR and EPR spectroscopy, elemental analysis, chromatography, and viscosimetry that radicals formed during the low-temperature action of molecular chlorine on acrylamide or its solutions in ethanol or glycerol initiate the polymerization reaction of acrylamide. It is established that during the low-temperature chlorination of pure acrylamide, polymerization takes place in the temperature range of 180–210 K with a polymer yield of ∼10%. The low-temperature chlorination of 20% solutions of acrylamide in ethanol or glycerol was performed to increase the product yield. It is shown that the low-temperature chlorination of acrylamide solution in glycerol increases the polymer yield by a factor of approximately two, and the content of chlorine in it falls by a factor of around ten. The low-temperature chlorination of acrylamide solution in ethanol did not lead to an increase in the polymer yield. A small reduction was noted in the chlorine content of the polymer.     

Theoretical analysis of reactions of electrophilic iodination and chlorination of benzene and polycyclic arenes in density functional theory approximation

Quantum-chemical method DFT B3LYP/6-311G* was applied to stage by stage thermodynamic calculation of reactions of electrophilic iodination of benzene, naphthalene, phenanthrene, and anthracene with iodine and iodine monochloride, and comparison with chlorination reactions was performed. The main distinction of iodination process from chlorination was an enhanced reversibility owing to protodeiodination. The reversibility of iodination grows with the electron-donor properties of aromatic substrates. The calculations permit an assumption that the chlorination of anthracene and phenanthrene with iodine monochloride occurs most probably through stages of electrophilic iodination-dehydroiodination.