New group 4 complexes and their use as homogeneous polymerization catalysts for the production of polyolefins

Tetrahydro-2-methylbenz[e]indanone (5) and tetrahydro-2-methyl benz[f]indanone (11) were produced from the reaction of 2-bromoisobutyryl bromide with tetralin, contrary to what has been previously published in the literature. Indanones 5 and 11 were readily converted into their corresponding indene derivatives tetrahydro-2-methylbenz[e]indene (6) and tetrahydro-2-methylbenz[f]indene (12), respectively. Two new half sandwich titanium trichlorides based on 6 and 12 were synthesized and were shown to polymerize styrene to s-PS with activities in the low 107 range. Two efficient synthetic routes to the novel titanatrane complexes, indenyl titanatrane (19) and 2-methylbenz[e]indenyl titanatrane ( 20) have been presented. These new titanatranes along with the known titanatranes, Cp titanatrane (17) and Cp* titanatrane ( 18) were tested as potential catalyst precursors for the polymerization of styrene and ethylene. Complex 17 was a very efficient catalyst for the polymerization of ethylene at 0°C, exhibiting a 100 fold increase over its corresponding trichloride derivative (CpTiCl3) Complex 18 proved to be the most versatile catalyst producing very high activities in the polymerization of styrene and moderate activities in the polymerization of ethylene. A new versatile synthetic route to substituted alkyl bridged bis-indanones and bis-indenes was developed. In addition, these bis-indenes can be employed as useful ligands in the synthesis of ansa-titanocenes. Ansa-titanocene complexes 22 and 63 were active in catalyzing the polymerization of olefins when activated by MAO, exhibiting activities of ca. 1 × 107 for the polymerization of ethylene and ca. 1.5 × 104 in catalyzing the polymerization of propylene. Four new C1 symmetric metallocenes containing a substituted indenyl moiety were synthesized. Metallocenes 68– 70 and 72 were active for both the polymerization of ethylene and propylene when activated with MAO. In general, diphenylsilylene-bridged catalysts produce polymers of higher molecular weights than do dimethylsilylene-bridged catalysts. Overall, one obtains a higher activity but polymers of lower molecular weights with ethylene-bridged catalysts versus silylene-bridged catalysts. In addition, four new C1 symmetric metallocenes containing 2,7-disubstituted fluorenyl moieties were synthesized. Three of the four metallocenes, 86–88, were highly active for the polymerization of both ethylene and propylene. In general, the most sterically hindered catalysts were more active and produced polymers of higher molecular weights than do their less hindered counterparts

Simple Epoxide Formation for the Organic Laboratory Using Oxone

We present an epoxide formation experiment for a second-semester organic chemistry laboratory. This oxidation utilizes Oxone, a commercially available oxidizing agent, in the industrially relevant process of epoxide formation. The oxidant performing the oxidation is dimethyldioxirane, which is formed in situ. This experiment demonstrates a simple synthesis of an epoxide and formation of a secondary oxidizing agent

A Simple SN2 Reaction for the Undergraduate Organic Laboratory

A simple procedure for the synthesis of n-butyl naphthyl ether is presented. This procedure represents an easy method for the production of an aryl ether by an SN2 reaction, uses ethanol as an environmentally friendly solvent, and does not require the use of a lachrymator. Product isolation is done by pouring the reaction mixture over ice and collecting the solid by suction filtration. Students typically recover from 7–95% of the ether

A Solvent-Free Claisen Condensation Reaction for the Organic Laboratory

An experiment involving the Claisen condensation reaction for a first-year organic chemistry laboratory is presented. Claisen condensations are routinely covered in organic textbooks but owing to the long reaction times required to reach equilibrium in solution they are seldom explored in the undergraduate teaching laboratory. In this experiment, potassium tert-butoxide and ethyl phenylacetate are heated to 100 °C for 30 minutes under solvent-free conditions to produce 2,4-diphenyl acetoacetate in 80% yield. The solvent-free nature of this procedure greatly reduces the quantity of waste generated by students relative to typical carbonyl condensation experiments

Cautionary Comments (author response)

Reply to concerns about a safety factor in the paper, “A Solvent-Free Oxidation of Alcohols in an Organic Laboratory

Cautionary Comments (author response)

Reply to concerns about a safety factor in the paper, “A Solvent-Free Oxidation of Alcohols in an Organic Laboratory

Technology for the Organic Chemist: Three Exploratory Modules

The ability to use computer-based technology is an essential skill set for students majoring in chemistry. This exercise details the introduction of appropriate uses for this technology in the organic chemistry series. The incorporation of chemically appropriate online resources (module 1), scientific databases (module 2), and the use of a chemical drawing program (module 3) are detailed here

A Solvent-Free Oxidation of Alcohols in an Organic Laboratory

An oxidation experiment for a first-year organic chemistry class is presented. This oxidation utilizes a solid mixture of CuSO4•5H2O and KMnO4 prepared by mortar and pestle. The oxidations take place under solvent-free conditions and near quantitative yields are obtained for the reactions. Thin-layer chromatography is used to monitor the progress of the reaction. This experiment provides for the simple oxidation of a secondary alcohol to a ketone using a relatively nontoxic oxidizing agent under solvent-free conditions

Projects That Assist with Content in a Traditional Organic Chemistry Course

Projects that engage undergraduate students in content-based courses, such as organic chemistry, must relate to the material and provide useful tools for the divergent needs of the students. There are few examples of these types of projects in the literature. Herein, we describe two projects, the reaction notebook and the end-of-semester synthesis activity. Each project is designed to stimulate student ownership of the material and leads to engagement with the content of the course

Solvent-Free Conversion of alpha-Naphthaldehyde to 1-Naphthoic Acid and 1-Naphthalenemethanol: Application of the Cannizzaro Reaction

The Cannizzaro reaction is routinely covered in organic textbooks, but owing to the shortage of suitable procedures for the undergraduate teaching laboratory, this reaction is seldom performed in a first-year organic chemistry class. In this experiment, powdered potassium hydroxide and α-naphthaldehyde are heated under solvent-free conditions to produce 1-naphthoic acid and 1-naphthalenemethanol in 86% and 79% yields, respectively. The solvent-free nature of this procedure greatly reduces the quantity of waste generated by students relative to the typical solvent-based method of preparation. Note:Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information will be required for access. Users not affiliated with Butler University should contact their local librarian for assistance in locating a copy of this article