3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

Chemical Routes for the Transformation of Biomass into Chemicals

Structural polymers are susceptible to damage in the form of cracks, which form deep within the structure where detection is difficult and repair is almost impossible. Cracking leads to mechanical degradation of fibre-reinforced polymer composites; in microelectronic polymeric components it can also lead to electrical failure. Microcracking induced by thermal and mechanical fatigue is also a long-standing problem in polymer adhesives. Regardless of the application, once cracks have formed within polymeric materials, the integrity of the structure is significantly compromised. Experiments exploring the concept of self-repair have been previously reported, but the only successful crack-healing methods that have been reported so far require some form of manual intervention. Here we report a structural polymeric material with the ability to autonomically heal cracks. The material incorporates a microencapsulated healing agent that is released upon crack intrusion. Polymerization of the healing agent is then triggered by contact with an embedded catalyst, bonding the crack faces. Our fracture experiments yield as much as 75% recovery in toughness, and we expect that our approach will be applicable to other brittle materials systems (including ceramics and glasses).

Autonomic healing of polymer composites

In recent years, the olefin metathesis reaction has attracted widespread attention as a versatile carbon−carbon bond-forming method. Many new applications have become possible because of major advances in catalyst design. State-of-the-art ruthenium catalysts are not only highly active but also compatible with most functional groups and easy to use. This Account traces the ideas and discoveries that were instrumental in the development of these catalysts, with particular emphasis on (PCy3)2Cl2RuCHPh and its derivatives. The discussion includes an analysis of trends in catalyst activity, a description of catalysts coordinated with N-heterocyclic carbene ligands, and an overview of ongoing work to improve the activity, stability, and selectivity of this family of L2X2RuCHR complexes.

http://web4.uwindsor.ca/users/j/jlichaa/reference.nsf/0/10ff8b04ff3a317885256d88005720f6/$FILE/acr-2001-34-18-metath-grubbs.pdf

The Development of L2X2RuCHR Olefin Metathesis Catalysts: An Organometallic Success Story

Synthesis and activity of a new generation of ruthenium-based olefin metathesis catalysts coordinated with 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene ligands.

The reactions of RuCl2(PPh3)3 with a number of diazoalkanes were surveyed, and alkylidene transfer to give RuCl2(CHR)(PPh3)2 (R = Me (1), Et (2)) and RuCl2(CH-p-C6H4X)(PPh3)2 (X = H (3), NMe2 (4), OMe (5), Me (6), F (7), Cl (8), NO2 (9)) was observed for alkyl diazoalkanes RCHN2 and various para-substituted aryl diazoalkanes p-C6H4XCHN2. Kinetic studies on the living ring-opening metathesis polymerization (ROMP) of norbornene using complexes 3−9 as catalysts have shown that initiation is in all cases faster than propagation (ki/kp = 9 for 3) and that the electronic effect of X on the metathesis activity of 3−9 is relatively small. Phosphine exchange in 3−9 with tricyclohexylphosphine leads to RuCl2(CH-p-C6H4X)(PCy3)2 10−16, which are efficient catalysts for ROMP of cyclooctene (PDI = 1.51−1.63) and 1,5-cyclooctadiene (PDI = 1.56−1.67). The crystal structure of RuCl2(CH-p-C6H4Cl)(PCy3)2 (15) indicated a distorted square-pyramidal geometry, in which the two phosphines are trans to each other, and the alkyli...

Synthesis and Applications of RuCl2(CHR‘)(PR3)2: The Influence of the Alkylidene Moiety on Metathesis Activity

In einem Verfahren zur Oligomerisierung von C¶6¶-Olefinen durch Umsetzung eines C¶6¶-Olefine enthaltenden Reaktionsgemisches an einem Nickel enthaltenden Festbettkatalysator, wird die Umsetzung am Festbettkatalysator mit einem Umsatz zu oligomerisierten C¶6¶-Olefinen, bezogen auf das Reaktionsgemisch, von maximal 30 Gew.-% gefahren.

Verfahren zur Oligomerisierung von C¶6¶-Olefinen

A homogeneous catalyst containing ruthenium complexes is used in the production of olefinic 6 carbon (C) compounds (I), comprising hex-3-en-1,6-dioic acid, diester or diamide, -dialdehyde, -dinitrile or mixed difunctional compounds of this type, by catalytic auto- or co-metathesis (disproportionation) of the corresponding but-3-ene or 4-alkyl- or (alkyl)aryl-but-3-ene compound(s) (II). A homogeneous catalyst containing ruthenium compounds or complexes is used in the production of olefinic 6 carbon (C) compounds of formula (I), comprising hex-3-en-1,6-dioic acid, diester or diamide, -dialdehyde, -dinitrile or mixed difunctional compounds of this type, by catalytic auto- or co-metathesis (disproportionation) of the corresponding but-3-ene or 4-alkyl- or (alkyl)aryl-but-3-ene compound(s) (II) of formulae (IIA) and/or (IIB), E-CH2-CH=CH-CH2-E (I) R-CH=CH-CH2-E (IIA) R -CH=CH-CH2-E (IIB) E, E = -CHO, -COOH, -COOR , -C(O)NR R or -CN; R, R = hydrogen (H), 1-12 C alkyl, 6-12C aryl or 7-13C alkylaryl; R , R , R = H, 1-12C alkyl or 7-13C aralkyl.

Process for the preparation of substituted olefins

<h3>Objective:</h3> Describe a case of Manganism encountered in Zambia. <h3>Background:</h3> Manganism is a neurodegenerative syndrome due to manganese toxicity and its excessive accumulation in the brain. <h3>Design/Methods:</h3> Case presentation <h3>Results:</h3> A 37-year-old man presented with a four-month history of mild, intermittent headache and three-month history of chest pain, dry cough and symmetrical distal-predominant paresthesias. He developed progressive cognitive decline associated with slowness in talking, low volume speech and difficulty completing activities of daily living two months prior to presentation. He reported fever and night sweats. Past medical history was unremarkable. Social history only notable for working as a manganese smelter for the past eight years. Neurological exam revealed memory and language deficits with psychomotor slowing, subtle left upper motor neuron facial weakness, hypomimia, bradykinesia and had a hyperkinetic tongue and upper limb tremor with normal tone and power in all limbs. Deep tendon reflexes were normal, but frontal release signs and an applause sign were present. Small and large fiber length-dependent sensory loss was noted with a cock-walk gait. MRI brain with gadolinium showed non-enhancing symmetric T1 hyperintensities in the globus pallidum and midbrain with corresponding T2 hypointensities in the same areas. <h3>Conclusions:</h3> A diagnosis of Manganism was made based on clinical history, strong occupational exposures, and neurological examination and imaging findings. Blood manganese levels and other heavy metals could not be obtained due to unavailability of tests in our setting, although blood manganese levels are often normal when obtained in cases of Manganism. The cough, headache, chest pain and fever were ascribed to metal fume fever and improved after a three-month withdrawal of manganese exposure, though neurologic symptoms did not improve during this period. This case demonstrates the importance of thorough history (including social history), examination, and correlation with limited investigations in diagnosing even rare diseases in resource-limited settings. <b>Disclosure:</b> Dr. Munkombwe has nothing to disclose. Dr. Asukile has nothing to disclose. Dr. Schwab has nothing to disclose. The institution of Dr. Saylor has received research support from National Institutes of Health. The institution of Dr. Saylor has received research support from National Multiple Sclerosis Society. The institution of Dr. Saylor has received research support from American Academy of Neurology. The institution of Dr. Saylor has received research support from United States Department of State. Dr. Saylor has a non-compensated relationship as a Member of multiple committees and task forces focused on improving access to MS medications to people across the world with Multiple Sclerosis International Federation that is relevant to AAN interests or activities. Dr. Saylor has a non-compensated relationship as a Member of the Neurology and COVID19 committee with World Health Organization that is relevant to AAN interests or activities. Dr. Saylor has a non-compensated relationship as a Member of the International Outreach Committee, Junior and Early Career Membership Committee, and Educational Innovation Commitees with American Neurological Association that is relevant to AAN interests or activities. 

Parkinsonism in a Zambian Man with an unusual occupational exposure (P3-4.002)

The present invention relates to a process for preparing alcohol mixtures to give contains a) a hydrocarbon mixture which contains cyclopentene and at least one acyclic mono-olefin, is reacted in a metathesis reaction, b) isolated from the reaction mixture of the metathesis an olefin fraction, which essentially contains olefins having 6 to 12 carbon atoms, c) optionally at least partially subjected to the olefin contained in the di- or poly-unsaturated compounds to selective hydrogenation to mono-olefins, and d) optionally selectively hydrogenated olefin catalytically hydroformylated by reaction with carbon monoxide and hydrogen, and hydrogenated, Alcohol mixtures which are obtainable by such a process, a process for the esterification of the alcohol mixtures, the ester so obtained and the use thereof.

Peter Schwab

Papers

Verfahren zur Oligomerisierung von C¶6¶-Olefinen

Process for the preparation of substituted olefins

Parkinsonism in a Zambian Man with an unusual occupational exposure (P3-4.002)

Process for the preparation of alcohol mixtures

Ruthenium und Osmium Metall-Carben-Komplexe von hoher Metathese Aktivität