Dodecene addition

Detergents have been manufactured from long-chain alkenes and sulfuhc acid, especially those obtained from shale oil or cracking of petroleum wax. These are sulfated with 90—98 wt % acid at 10—15°C for a 5-min contact time and at an acid—alkene molar ratio of 2 1 (82). Dialkyl sulfate initially forms when 96 wt % acid is added to 1-dodecene at 0°C, but it is subsequently converted to the hydrogen sulfate in 80% yield upon the further addition of sulfuhc acid. The yield can be increased to 90% by using 98 wt % sulfuhc acid and pentane as the solvent at -15°C (83). 

The mechanism of the polymerization contains ionic intermediate steps. The free H+ goes to a carbenium ion and, as shown in route B, rearranges to form tetrapropylene. It is highly likely that this actual tetrapropylene exists only in very small concentrations. The product variety is explained by the rearrangement of the carbenium ion to dodecene isomers according to route C. In addition, short-chain olefins formed by fragmentation (route D). Polymerization proceeds at almost 100% to mono olefins. Aromatics, paraffins, and diolefins exist only in trace amounts. The propylene tetramer is best characterized by its distillation range. 

Since it is well known that the higher the olefin, the more difficult it is to hydroformylate, we tried our approach on 1-dodecene. We found that when we used 50 50 ethanol/water (R24) and CTAB only (R33) systems they showed no activity for hydroformylation of 1-dodecene whereas, the addition of surfactant to the 50 50 ethanol/water mixture (R27) dramatically increased the reaction rate, as well as the selectivity. 

In summary, what we have found is that the combination of a thermomorphic system and a surfactant is very effective for the hydroformylation of 1-octene and 1-dodecene. We believe that although a 90 10 ethanol/water and heptane system becomes miscible at 70°C, the additional water in a 50 50 ethanol/water and heptane system raises the miscibility temperature to >100°C. When a surfactant is added, the miscibility temperature is lowered and the biphasic solution becomes monophasic below the reaction temperature, resulting in good reaction rates. In addition, the presence of the surfactant also enhances the selectivity compared to the completely homogeneous system from 1.8 to 5.3 L/B... 

Cross-metathesis of methyl oleate with 3-hexene under similar conditions led, in addition to the above products [Eq. (54)], to 3-dodecene and the methyl ester of 9-dodecenoic acid. 

Abstract A relatively small number of mammalian pheromones has been identified, in contrast to a plethora of known insect pheromones, but two remarkable Asian elephant/insect pheromonal linkages have been elucidated, namely, (Z)-7-dodecen-1-yl acetate and frontalin. In addition, behavioral bioassays have demonstrated the presence of a chemical signal in the urine of female African elephants around the time of ovulation. Our search for possible ovulatory pheromones in the headspace over female African elephant urine has revealed for the first time the presence of a number of known insect pheromones. This search has been facilitated by the use of a powerful new analytical technique, automated solid phase dynamic extraction (SPDE)/GC-MS, as well as by novel macros for enhanced and rapid comparison of multiple mass spectral data files from Agilent ChemStation . This chapter will focus on our methodologies and results, as well as on a comparison of SPDE and the more established techniques of solid phase microextraction (SPME) and stir bar sorptive extraction (SBSE). 

Silica-alumina particles coated with a permselective silicalite membrane is almost completely selective in the formation of p-xylene in the disproportionation of toluene.402 Friedel-Crafts alkylations were performed in ionic liquids. The strong polarity and high electrostatic fields of these materials usually bring about enhanced activity.403 404 Easy recycling is an additional benefit. Good characteristics in the alkylation of benzene with dodecene were reported for catalysts immobilized on silica or MCM-41 405... 

Dimethylcarbene The usual methods for generation of carbenoids lead to poor results in the case of dimethylcarbene. The most satisfactory method involves generation in the presence of an alkene by a-elimination with n-butyllithium from 2,2-dibromopropane (which must be completely free from acetone or 2-bromoacetone), used after a detailed study of cyclopropanation of tetramethylethylene (equation I). n-Butyllithium is superior to methyl- or isopropyllithium. Addition of TMEDA or KOC(CH3)3 completely supresses cyclopropanation. Yields are improved by a lower reaction temperature. In all experiments, 35-45% of the alkene is recovered. Yields decrease with a decrease of alkyl substituents on the double bond thus the yield is only 9% in the case of l-dodecene. No cyclopropane was obtained from 2-norbomene. 

Dodecene is an intermediate for surfactants, mainly through two routes. One, the larger user, produces dodecylbenzene sulfonate for anionic detergents. The other goes through the oxo process to tridecyl alcohol, which then is converted into a nonionic detergent by the addition of alkylene oxides. 

As a test reaction, the alkylation of benzene with dodecene was chosen. The batch reactor system consisted of a round-bottomed flask (slurry reactor) provided with a cooler, gas-inlet valve, and sampling exit. A magnetic stirrer equipped with a thermostat and a silicon oil bath were used to maintain the reaction temperature and ensure the homogeneity of reactants. The catalyst was weighed in the reactor and then benzene was added according to the proportion desired, followed by the addition of dodecene. 

There is little rate data available for addition and abstraction reactions involving higher alpha-olefins. Where such data are available, they have usually been obtained from lower temperature studies (12,13,14), However, the available information indicates that addition should be competitive with abstraction in the temperature range of this study. For example, Steacie s data for ethyl radical reactions with 1-hexene and 1-heptene indicate that at 525°C, the addition rate would be about seven-tenths of the abstraction rate. For dodecene, one would expect this ratio to decrease because of the increase in abstractable hydrogen, but addition should still be a significant pathway. For methyl radicals and H atoms, available data (13,14) indicate that addition is somewhat faster relative to abstraction. 

The relative contributions of the three proposed reaction paths remain to be determined. The products from both the retro-ene and the addition reactions can be predicted with some quantitative certainty. For dodecene, the former produces only 1-nonene and propylene. The product distributions from the addition paths should be identical to those from the cracking of the corresponding paraffins. These product distributions can be predicted using the method of Rice and Kossiakoff (16). This approach parallels excellently with experiments (16,17). (From available data we estimate its accuracy as d=10%.) For dodecene, the addition of hydrogen atoms, methyl radicals, and ethyl radicals will produce Ci2H25, Ci3H27, and Ci4H29 parent radicals. The product distributions predicted by the Rice-Kossiakoff method for the decomposition of these radicals at 525°C are shown in Table IV. 

Table IV. Calculated Product Distributions for Radical Addition to Dodecene at 525°C...

The estimated relative contributions of the three paths for dodecene cracking under a variety of conditions are shown in Table V. Two trends are visible in the data. First, at constant temperature and increasing dodecene partial pressure, the relative importance of the retro-ene path decreases while that of the abstraction path increases. The contribution of the addition path remains constant. The average estimated relative contributions of the retro-ene reaction at 525°C taken from Table V correspond to a reaction order of 0.95 0.4 in dodecene this satisfies the requirement that retro-ene reaction be first order. 

The reason for the increase in the importance of the H abstraction path with increasing pressure is more subtle. While the reaction order for the radical addition path is 1.33 (the same as the overall reaction), the abstraction path is 1.40 order in dodecene (from the data in Table V). This may be attributable to a decrease in [H ] with increasing pressure because more ethyl radicals are stabilized to ethane and fewer are decomposed to ethylene and H- as the pressure is increased (see Figure 7). If H atoms are the most efficient addition species, a decrease in their relative concentration would result in a relative decrease in the contribution of the addition path and a corresponding increase in the role of the H abstraction route. 

The second trend is that at constant dodecene partial pressure as the temperature is increased, the relative importance of the retro-ene reaction decreases slightly, while the H abstraction path and the radical addition path show much more marked temperature dependences. The former increases while the latter decreases in relative importance. This suggests that the activation energy for hydrogen abstraction is significantly higher... 

Given the /3-scission hypothesis, an examination of possible dodecenyl radicals indicates no reasonable mechanism of formation of Ci0H20 or CnH22. These products are formed only from the radical addition path. They can be used then to predict the relative importance of this path, XA. Decene is used to do this since it is better separated by GC from the corresponding diolefin than is undecene. XA is given by the ratio of the predicted value for decene from Table IV to the actual experimental yield. (Values for hydrogen atom addition are used here they are fairly close to those for CH3 and C2H5- addition, and available rate data (13, 14) indicate that H- atoms are the most likely radicals to add to dodecene.)... 

Conjugated diynes can be reduced to cis enynes by the well-known hydroboration-protonolysis sequence . cw-5-Dodecen-7-yne (215) is obtained from the diyne 213 in 76% yield as shown in equation (23). The orientation of addition of the disiamyl-borane was established by using CH3CO2D in the second step. Addition of a second mole of disiamylborane to 214 is very slow, but reduction to the cis,cis diene can be accomplished by using dicyclohexylborane instead . 

When 1-dodecene, tellurium dioxide in coneentrated hydroehloric acid, and ethanol or isopropanol were reacted and the products reduced with disodium disulfite, bis[2-hydroxydodecyl] ditellurium (m.p. 64°) was isolated in 21 % yield (R OH = ethanol) or 29% yield (R = /-C3H7OH) in addition to the corresponding bis[2-alkoxydodecyl] ditelluriums. Bis[2-tetrahydrofurylmethyl ditellurium (62% yield) and his[henzo-2-dihydrqfurylmethy[ ditellurium (83% yield) were similarly prepared . ... 

In addition, Ox-Ti-P samples were found to be efficient catalysts in the epoxidation of bulky organic substrates such as norbornylene (Table 2). For comparison, the reaction was also carried out in the absence of any catalyst. As seen, the catalytic activity of Ox-Ti-p samples was comparable to that of Ti-P. We also obtained very high conversions in the epoxidation of 1-dodecene over Ox-Ti-P. 

Pyrolysis process for poly(2-hydroxyethyl methacrylate) occurs similarly to that for other methacrylic acid esters. The formation of 2-methyl-2-propenoic acid 2-hydroxyethyl ester, the monomer, shows that unzipping is a significant part of the process. Some other compounds in the pyrolysate also are generated from the polymer cleavage, such compounds including 2-methyl-2-propenoic acid ethenyl ester, propanoic acid, 2-methyl-2-propenoic acid, ethanol, etc. On the other hand, some compounds are not expected in the pyrolysate and they can be impurities or additives. Examples of such compounds are the hydrocarbons (undecene, dodecane, 1-dodecene, etc.), the esters of ethylene diol and the free 1,2-ethandiol, etc. The initiator AIBN and its decomposition products 2-methyl-2-propenenitrile and 2-methylpropanenitrile identified in the pyrolysate show that the polymer was obtained using AIBN as initiator. 

The structural similarities between the putative mammalian chemosignals and the pheromones identified previously in the insect world are quite striking. The farnesenes [257, 258] (entries 66, 67) and 2-heptanone [259] (entry 68) have been implicated previously as insect pheromones. There is only one double bond distinguishing the male mouse pheromone 3,4-dehydro-exo-brevicomin (entry 65) from a bark beetle pheromone [260], brevicomin. In addition, the elephant pheromone (Z)-7-dodecen-l-yl acetate (entry 69) is also known to be an insect pheromone [259]. While the potency may not compare to the insect system, investigators are beginning to find evidence that many mammals ranging from pigs to elephants can have a pheromone-type response to a sniff of secretions even humans appear to respond [261],... 

In addition to the alkylation activity, all acid catalysts possess the ability to shift the olefinic double bond position along the chain. Researchers have shown that the position of the phenyl group in the final product is specific to the catalyst system used. Table 4 summarizes some of this work for the reaction of 1-dodecene (112-41-4) with benzene. 

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