Ruthenium catalyzed equilibrium ring-opening metathesis polymerization of cyclopentene

Polypentenamer was synthetized by equilibrium ring-opening metathesis polymerization (ROMP) using well-defined ruthenium catalyst systems. It was found that the equilibrium time is influenced by the catalyst loading or the catalyst activity, however as expected, the overall cyclopentene conversion is determined only by the applied reaction temperature. Equilibrium of the growing chain and monomer was observed and the activation enthalpy and entropy were determined as: ΔH = −5.6 kcal mol^(−1); ΔS = −18.5 cal mol^(−1) K^(−1). So far these values are the lowest which are reported for cyclopentene polymerization catalyst systems. This unique feature of the equilibrium polymerization opens a way for the synthesis of durable, environmentally friendly elastomers where tires can be not only synthetized but also readily recycled by the same transition metal catalyst system

Katalízis karbén-komplexekkel = Catalysis with carbene complexes

Rendkívül hatásos új kobalt-katalizált szén-szén kötéshez vezető, általánosan alkalmazható szintézis utat fedeztünk fel karbonsav-származékok előállítására, amelynek lényege egy ketén intermedier képződése a diazo-csoport szén-monoxiddal való kicserélése által. A karbonsav származékok a ketén intermedierből vezethetők le változatos B-H típusú reagensekkel. A karbonsav származékok 100%-ot megközelítő kitermeléssel nyerhetők ezen egyszerűen megvalósítható egyreakcióedényes katalitikus reakcióval. A trimetilszilil-diazometán Co2(CO)8-katalizált karbonilezését szobahőfokon és légköri nyomáson alkalmas preparatív módszerré fejlesztettük trimetilszilil-ketén minden eddiginél egyszerűbb előállítására. Ródium- és palládium-komplexek alkalmas katalizátoroknak bizonyultak CFC és HCFC vegyületek homogénfázisú katalitikus dehidrohalogénezésére. A kidolgozott módszerek lehetővé teszik e környezetre káros anyagok hasznos termékekké való átalakítását. | We discovered a very efficient new cobalt-catalyzed carbon-carbon bond-forming synthesis leading to carboxylic acid derivatives. The essence of this high-yield one-pot synthesis is the catalytic substitution of a diazo group by carbon monoxide to form a ketene intermediate, which can be trapped with different B-H type reagents to give various carboxylic acid derivatives in up to 100% yield. The Co2(CO)8-catalyzed carbonylation of trimethylsilyldiazomethane at ambient conditions give trimethylsilylketene in excellent isolated yields, which seems to be the best preparative method so far to obtain this precious synthetic intermediate. Rhodium and palladium complexes proved to be effective catalysts in hydrodechlorination of CFC and HCFC compounds in homogeneous phase. By this way these harmful chemicals can be converted to useful products

Detecting Vital Signs with Wearable Wireless Sensors

The emergence of wireless technologies and advancements in on-body sensor design can enable change in the conventional health-care system, replacing it with wearable health-care systems, centred on the individual. Wearable monitoring systems can provide continuous physiological data, as well as better information regarding the general health of individuals. Thus, such vital-sign monitoring systems will reduce health-care costs by disease prevention and enhance the quality of life with disease management. In this paper, recent progress in non-invasive monitoring technologies for chronic disease management is reviewed. In particular, devices and techniques for monitoring blood pressure, blood glucose levels, cardiac activity and respiratory activity are discussed; in addition, on-body propagation issues for multiple sensors are presented

Concert recording 2016-04-02

[Track 01]. Moondance / John Stevens -- [Track 02]. Turkish march / W.A. Mozart ; translated by Keith Mehlan -- [Track 03]. To a wild rose from Woodland sketches / E. MacDowell ; arranged by J. Lockhart -- [Track 04]. Fantasy movements. Adagio - Allegro vivace ; [Track 05]. Allegro ; [Track 06]. Slowly ; [Track 07]. Very fast & manic ; [Track 08]. Adagio - Allegro / Anthony Plog -- [Track 09]. Saint James infirmary / Joe Primrose ; arranged by Mike Forbes

Guest Artist: Western Brass Quintet

This recital is in partial fulfillment of the graduation requirements for the degree, Master of Music in Performance. Kemp Recital HallApril 7, 2015Tuesday Evening7:30 p.m

Guest Artists Recital: Western Brass Quintet: Donald Bullock, Trumpet; Stephen Jones, Trumpet; Neil Sanders, Horn; Russell Brown, Trombone; Robert Whaley, Tuba; September 27, 1976

Hayden AuditoriumMonday EveningSeptember 27, 19768:00 p.m

Student Brass Quintet: Robert Fund, Trumpet; Jim Cassens, Trumpet; Peter Johnson, Horn; David Kotowski, Trombone; Brian Frederiksen, Tuba; October 15, 1973

Hayden AuditoriumMonday EveningOctober 15, 19738:15 p.m

Synthesis of recyclable tire additives via equilibrium ring-opening metathesis polymerization

Linear <i>trans</i>-polypentenamers are highly desired materials among synthetic tire additives due to their comparable physical properties to natural rubber. <i>trans</i>-Polypentenamer can be prepared by equilibrium ring-opening metathesis polymerization (ROMP) using well-defined ruthenium catalyst systems. This unique feature of the equilibrium polymerization reaction opens a way for the synthesis of durable, environmentally benign elastomers where polymers including synthetic tire additives can be synthesized and readily recycled using the same transition metal catalyst system. The addition of silica fillers significantly improves the physical properties of the composite materials in comparison to the use of polymeric material. It is also known that the structural effects and the polymer–filler surface interaction are of prime importance. Herein, we report on the synthesis of silica filler compatible recyclable polypentenamer copolymers via equilibrium ROMP of cyclopentene <b>1</b> and 4-(triethoxy)­siloxy cyclopentene <b>11</b>. It has been demonstrated that polypentenamer tire additives can be synthesized via equilibrium ROMP affording polymers with high yields (>80%) at 0 °C and can be readily depolymerized at 40 °C and/or under diluted conditions using the same metathesis catalyst systems. Furthermore, the polypentenamer can also be synthesized in neat at room temperature and at very low (10⁵) monomer/catalyst ratio. This methodology is based on the synthesis of polyolefins utilizing a ruthenium-based metathesis catalyst via equilibrium ROMP of cyclopentenes and their silylated derivatives

One-pot Synthesis of 1,3-Butadiene and 1,6-Hexanediol Derivatives from Cyclopentadiene (CPD) via Tandem Olefin Metathesis Reactions

A novel tandem reaction of cyclopentadiene (CPD) leading to high value linear chemicals via ruthenium catalyzed ring opening cross metathesis (ROCM), followed by cross metathesis (CM) is reported. The ROCM of cyclopentadiene (CPD) with ethylene using commercially available 2nd gen. Grubbs metathesis catalysts (1‐G2) gives 1,3‐butadiene (BD) and 1,4‐pentadiene (2) (and 1,4‐cyclohexadiene (3)) with reasonable yields (up to 24 % (BD) and 67 % (2+3) at 73 % CPD conversion) at 1–5 mol % catalyst loading in toluene solution (5 V% CPD, 10 bar, RT) in an equilibrium reaction. The ROCM of CPD with cis‐butene diol diacetate (4) using 1.00 ‐ 0.05 mol % of 3rd gen. Grubbs (1‐G3) or 2nd gen. Hoveyda‐Grubbs (1‐HG2) catalysts loading gives hexa‐2,4‐diene‐1,6‐diyl diacetate (5), which is a precursor of 1,6‐hexanediol (an intermediate in polyurethane, polyester and polyol synthesis) and hepta‐2,5‐diene‐1,7‐diyl diacetate (6) in good yield (up to 68 % or TON: 1180). Thus, convenient and selective synthetic procedures are revealed by ROCM of CPD with ethylene and 4 leading to BD and 1,6‐hexanediol precursor, respectively, as key components of commercial intermediates of high‐performance materials