Piperylene concentrate is a complex mixture of 5-carbon unsaturated hydrocarbons obtained as by-products when naptha or gas oils are cracked. The major component in this mixture is 1,3-pentadiene. The cyclodimerization of 1,3-pentadience in piperylene concentrate by using a nickel catalyst was studied. Various types of ligands were used in the preparation of the nickel catalyst. The effect of each ligand on activity of the catalyst in dimerization of diene, on conversion, and on yield of reaction were investigated. The effect of reaction conditions, such as temperature, pressure, and reaction time, on conversion of monomer, yield of dimer, and selectivity of catalyst were determined. The activity of catalyst on domerization of pure 1,3-pentadiene and isoprene also were studied. Production of various by-products during cyclodimerization of 1,3-pentadiene in piperylene concentrate mixture was a major problem in separation of dimer from these by-products.

Piperylene concentrate, the five-carbon olefin and diolefin by-product of ethylene production, is being produced in increasing quantities as liquid feedstocks become more prevalent. At present, the concentrate is used primarily in resin production for the adhesives industry. Since this use is economically unattractive, a separation of the concentrate into pure compounds is industrially desirable. The evaluation of the effectiveness of several solvents for extractive distillation of piperylene concentrate was performed. This study resulted in the selection of acetonitrile as the most effective and most economical solvent investigated. Various distillation conditions were studied and optimization was based on these results.

Piperylene concentrate is a complex mixture of 5-carbon unsaturates. The major components are trans-1,3-pentadiene and cyclopentene. The object of this work is to form a product high in cyclopentene and a product high in the pentadienes, through the use of 13X zeolite molecular sives. Separation by molecular sieves is difficult because of the tendency of trans and cis pentadience to polymerize o the sieve and to thus decrease the adsorptive capacity of the sieve. Nitrogenous bases (dimethylamine, pyridine, and piperidine) were used in an attempt to neutralize any acid sites on the sieve. Dealumination by EDTA was used to decrease the number of electron deficient aluminum cations. cation exchange with iron, copper, potassium, and barium were used in an attempt to decrease polymerization. Silylation, esterification, and methylation were attempted to decrease the number of polymerization sites. The degree of polymerization inhibition achieved by the different treatment procedures was determined by a comparison of adsorptive capacity (g adsorbate/g sieve) and by percent desorption ((g recovered adsorbate/g adsorbate) X 100). The copper exchanged 13X sieve showed very high initial adsorptive capacity at 0.42 g adsorbate/g sieve and the highest percent desorption at nearly 100% for the first two runs. The methylated and silylated 13X sieves showed high adsorptive capacity but low percent desorption.

The vapor phase oxidation of 1.3-pentadiene, over heterogeneous catalysts, was investigated with the objective of producing 2,4-pentadienal and 2,4-pentadienoic acid. Copper and cobalt-molybdenum catalysts, both supported and unsupported, were utilized at various reaction temperatures, residence times and feed ratios. The matter of 1,3-pentadiene vaporization and introduction into the reactor system proved to be critical. Low temperature vaporization of the hydrocarbon and dilution with the oxidant, air, was found to be necessary to avoid polymerization of the feed. Alumina-supported catalysts were found to be very active, leading to severe cracking of the hydrocarbon feed and subsequent carbonization of the catalysts. Silica-supported catalysts did not suffer from this problem. At all conditional studied the oxidations were non-selective, with numerous products being observed. The desired product, 2,4-pentadienoic acid, was observed only in trace amounts over cobalt molybdate. 2,4-Pentadienal was observed over all catalysts. The highest yield of 2,4-pentadienal, 11%, occurred over cobalt molybdate.

Piperylene concentrate is a complex mixture of 5-carbon unsaturated hydrocarbons obtained as a by-product when naphtha or gas oils are cracked. The major component in this mixture is 1,3-pentadiene. During the course of this study, a number of trials, utilizing liquid phase reaction conditions, were made to investigate the geometric isomerization of 1,3-pentadiene and its separation from the piperylene concentrate. Isomerization was accomplished employing catalytic amounts of iodine at temperatures ranging from 0°C to reflux. Using this method, the maximum amount of trans-1,3-pentadiene obtained was 70% as compared to 51% in the piperylene concentrate. Recovery of the product was 90%, with the remainder being diiodo compounds and polymer. Isomerizations employing catalytic amounts of potassium tert-butoxide were also investigated. Using this anionic isomerization, the theoretical amount of trans-1,3-pentadiene (84% @ 20°C) was obtained in the product. The greatest drawback with this technique was the low recover (50%), due to the extensive polymer formation. Successful separation of 1,3-pentadiene from the mixture was accomplished through cuprous chloride complexing. Utilizing this technique, 54% of the 1,3-pentadiene was recovered from the mixture, with the separated product being 99.9% pure 1,3-pentadiene. Separation of trans-1,3-pentadiene from the mixture was accomplished through a Diels-Alder reaction with maleic anhydride. Since this dienophile will react readily with trans-1,3-pentadiene but not cis-1,3-pentadiene, this method offered an easy and efficient means of removing the former isomer from the mixture. In attempting to reverse this Diels-Alder, via pyrolysis, many products were obtained; including those present in the original mixture. The gas phase dehydrocyclization of 1,3-pentadiene was investigated in a 316 stainless steel tubular flow reactor utilizing various heterogeneous and homogeneous catalysts. The selectivity to cyclopentadiene was greatest (60%) in the presence of a hydrogen sulfide promoter. For all other catalysts, the selectivity remained relatively constant (30%). This constant selectivity over a wide range of parameters indicates that a significant amount of competing side reactions are prevailing within the preheater section of the apparatus.

The implementation of sustainable solvents and processes is critical to new developments in reducing environmental impact, improving net efficiency, and securing economic profitability in the chemical and pharmaceutical industries. In order to address the challenge of sustainability, researchers have used switchable solvents for both reaction and separation by utilizing a built-in switch to undergo a step change in chemical and physical properties. This allows us to facilitate reactions in the solvent then activate the switch to enable separation and facile product recovery. Subsequently, we can recover the solvent for reuse and avoid energy- or waste-intensive separation processes; thus we are developing and using these switchable solvents as sustainable and environmentally benign alternatives to traditional processes. In this research, we enable the sustainable scale-up of a switchable solvent - piperylene sulfone - a "volatile" and recyclable DMSO replacement. In the development of this process, we improved the reaction performances and developed a green purification method. Furthermore, we enable and demonstrate the implementation of a Meerwein-Ponndorf-Verley (MPV) reduction, a pharmaceutically relevant reaction, into a continuous flow platform. The innovation of continuous flow processes can replace traditional batch reaction technology, and is indeed a key research area that has been acknowledged by the pharmaceutical industry. Additionally, we utilize the switchable sulfone solvents, piperylene and butadiene sulfone, for reaction and separation of HMF produced from monosaccharides as an alternative to a process which has been limited by an inefficient separation step.

This work seeks to develop new solvents for environmentally benign chemical synthesis. Switchable solvents are a new class of compounds that change properties upon the application of some stimulus such as heat, UV light, or pH. We have developed the use of a new solvent, thiirane oxide, that has chemical properties similar to DMSO. Thiirane oxide, however, undergoes facile decomposition to two gases at temperatures above 100 C, which is much lower than the temperature required for removing DMSO. Thus we have a solvent with excellent solvation properties, but with a built-in switch for easier removal. However, thiirane oxide leaves behind sulfurous products which make the reverse reaction to reform the solvent unfeasible. We are also developing the use of another solvent, piperylene sulfone, which is expected to have good solvent properties, yet with decomposition products that can be reacted to reform the solvent. This thesis also details the work to date on piperylene sulfone. Gas-expanded liquids (GXLs) also show promise as a new reaction medium. In order to design solvent systems that take full advantage of this medium, we desire to understand the microstructure of these fluids. To that end, we are using cage reactions to probe solute-solvent and solvent-solvent interactions at the molecular level. This thesis discusses the current research on using cage reactions to probe the structure of GXLs.