摘要:
A process for the preparation of butyrolactones of the formula I ##STR1## where the substituents R.sup.1 and R.sup.2 are hydrogen, alkyl or hydroxyalkyl groups, or aryl and trialkylsilyl groups, if appropriate carrying inert: substituents, is described in which an alkyne of the formula IIR.sup.1 --C.tbd.C--R.sup.2 IIwhere the substituents have the meanings indicated above, is reacted under reducing conditions at elevated pressure and elevated temperature with carbon monoxide CO and hydrogen in the presence of a transition metal catalyst or with carbon monoxide and water in the presence of a transition metal catalyst.
摘要:
The process for carbonylating olefins with carbon monoxide in the presence of water, an alcohol or a carboxylic acid and a halogen-free catalyst comprises using a catalyst comprising nickel or a nickel compound and at least one of the metals of the group consisting of chromium, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver and gold, or a compound of these metals.
摘要:
A process for preparing tetrahydrofuran, which comprises reacting 1,4-butenediol diethers of the formulae I and/or IIRO--CH.sub.2 --CH.dbd.CH--CH.sub.2 --OR IRO--CH.sub.2 --CH.sub.2 .dbd.CH--CH.sub.2 --OR II,where the R radicals can be identical or different and are C.sub.1 -C.sub.15 -alkyl or cycloalkyl radicals, C.sub.6 -C.sub.12 -aryl radicals or C.sub.7 -C.sub.15 -aralkyl radicals, with water and hydrogen at from 20 to 300.degree. C. under from 1 to 300 bar in the presence of catalysts or catalyst combinations which comprise components which are both capable of hydrogenation and have acidic or basic centers and a novel process for preparing 1,4-butanediol diethers of the formula I by metathesis are described.The invention furthermore relates to the separate preparation of 1,4-butanediol monoethers of the formula IIIHO--CH.sub.2 --CH.sub.2 --CH.sub.2 --CH.sub.2 --OR III,where R has the meanings indicated for formulae I and II, for which purpose 1,4-butanediol diethers of the formulae I and/or II are reacted as claimed in claim 1 with water and hydrogen in the presence of a hydrogenation catalyst at from 20 to 300.degree. C. under from 1 to 300 bar.
摘要:
1,6-Hexanediol is prepared bya) Reacting epoxybutadiene in the presence of a metathesis catalyst with elimination of ethene to give bisepoxyhexatrienes of the formulae Ia and Ib ##STR1## and b) hydrogenating these bisepoxyhexatrienes with hydrogen to give 1,6-hexanediol.
摘要:
A process for selectively preparing a carboxylic acid by reacting an olefin with carbon monoxide in the presence of at least an equimolar amount of water with respect to the olefin at a temperature of from 50.degree. to 150.degree. C. and a pressure of from 30 to 150 bar and also in the presence of a halogen-free catalyst system consisting of rhodium or a rhodium compound and at least one nitrogen-containing heterocyclic compound as a promoter
摘要:
A process is described for preparing acid formates in which methyl formate is reacted with water and a basic compound having a pKa of the conjugate acid of the corresponding dissociation state of ≧3 measured at 25° C. in aqueous solution, the methanol formed is separated off and, optionally, the desired acid content is set by adding formic acid.
摘要:
The invention provides an anti-fogging agent comprising an ester product and at least one further anti-fogging agent. The invention also relates to shaped articles and polymer compositions comprising such anti-fogging agents, and the preparation and use thereof.
摘要:
The invention relates to a process for the preparation of methyl formate by reacting methanol with carbon monoxide at a pressure of from 0.5 to 10 MPa abs. and a temperature of from 50 to 150° C. in the presence of a metal alkoxide as catalyst in a reactor, in which a gas stream is withdrawn from the reactor, entrained methyl formate is removed from this gas stream by condensation, and all or some of the remaining gas stream is returned to the reactor as circulating-gas stream and a mean gas superficial velocity of from 1 to 20 cm/s is set in at least one region of the reactor in which the gas flows essentially in one direction.
摘要:
A device for performing fetotomy on a dead fetus or repositioning of a live fetus has a primary attachment in the form of a looped brace that is provided around a fetal limb within the birth canal of the mother animal and engages the armpit or groin of the fetus. An extension bar connects the brace to a tensioning device. A secondary attachment such as a cable or chain is attached at the foot of the fetal limb and connected to the tensioning device. The tensioning device is operated to provide tension between the brace and the secondary attachment, thereby placing the fetal limb in traction. Sufficient traction causes removal of the entire limb without exposing sharp bone edges. Variations of the device may be used for a fetal repositioning procedure.
摘要:
This invention relates to novel compounds F-18 radio-labeled amino-alcohols suitable for labeling or already labeled by 18F methods of preparing such a compound, compositions comprising such compounds, kits comprising such compounds or compositions and uses of such compounds, compositions or kits for diagnostic imaging by positron emission tomography (PET).