Abstract: The invention relates to a record carrier (1) comprising a pattern of substantially parallel tracks (2) for storing data in the form of marks, in which the data is encoded by means of a channel code. The record carrier further includes a watermark (3) which is provided by controlling the parameter of the channel code so as to introduce a predetermined run length distribution in the marks on the record carrier. Brightness differences are caused by introducing this run length distribution. The invention also relates to a device for reading a record carrier, a method of providing a watermark on the record carrier, and a device for providing a watermark on a record carrier.

Abstract: 2-trihalogenomethyl-3-halogeno-4-cyano pyrrole derivatives which are substituted in position 5 and optionally in position 1 are used as barnaclecide in antifouling paints, which can therefore be formulated as light- or bright-colored, particularly as bright white. The halogens in positions 2 and 3 are independently selected from the group consisting of florine, chlorine and bromine, preferably florine in position 2 and bromine in position 3. The substituent in position 5 is selected from the group consisting of C1-8 alkyl, C1-8 monohalogenoalkyl, C5-6 cycloalkyl, C5-6 monohalogenocycloalkyl, benzyl, phenyl, mono- and di-halogeno-benzyl or -phenyl, mono- and di-C1-4 alkyl benzyl or phenyl, and monohalogeno mono-C1-4-alkyl benzyl or phenyl, the halogen being selected from the group consisting of chlorine and bromine, prefereably chlorine; the most preferred substituent in position 5 is parachlorophenyl.

Abstract: Nitrophenylalkanols are prepared by hydroxyalkylation of nitrotoluene(s) by the reaction with an aldehyde in the presence of a solid catalyst prepared by depositing an alkali metal compound on an alumina support.

Abstract: Novel compounds of the formula I ##STR1## in which each of Y.sup.1 and Y.sup.2 independently represents a fluorine, chlorine or bromine atom and each of R.sup.1 and R.sup.2 independently represents a hydrogen atom or an alkyl group having up to 10 carbon atoms, or R.sup.1 and R.sup.2 together represent an alkylene group having from 2 to 5 carbon atoms, may be converted by the action of base into the corresponding dihalovinylcyclopropane carboxylic acids.

Abstract: When the reaction of aldehydes with alkali metal trihaloacetates is carried out in the presence of a highly polar aprotic solvent (DMF, DMSO), novel organic alkali metal carbonates, which are precursors of pyrethroid insecticides, are formed in high yields and at a high rate. Novel sulfonates and dihalophosphites, derived from these carbonates have also been claimed.

Abstract: Novel compounds of the formula I ##STR1## in which each of Y.sup.1 and Y.sup.2 independently represents a fluorine, chlorine or bromine atom and each of R.sup.1 and R.sup.2 independently represents a hydrogen atom or an alkyl group having up to 10 carbon atoms, or R.sup.1 and R.sup.2 together represent an alkylene group having from 2 to 5 carbon atoms, may be converted by the action of base into the corresponding dihalovinylcyclopropane carboxylic acids.

Abstract: Novel compounds of the formula I ##STR1## in which each of Y.sup.1 and Y.sup.2 independently represents a fluorine, chlorine or bromine atom and each of R.sup.1 and R.sup.2 independently represents a hydrogen atom or an alkyl group having up to 10 carbon atoms, or R.sup.1 and R.sup.2 together represent an alkylene group having from 2 to 5 carbon atoms, may be converted by the action of base into the corresponding dihalovinylcyclopropane carboxylic acids which are intermediates for preparing known pyrethroid insecticides.

Abstract: A process for the preparation of dihalovinyl compounds of the formula ##STR1## wherein each Hal is fluorine, chlorine or bromine, R.sup.1 is an optionally substituted hydrocarbyl group, R.sup.2 is a methyl group or a hydrogen atom, or R.sup.1 and R.sup.2 together with the carbon atom to which they are attached form cycloalkylidene group, which process comprises treating a trihalo compound of the formula ##STR2## wherein Hal, R.sup.1 and R.sup.2 have the above meanings and R.sup.3 is a hydrogen atom or ##STR3## in which M is an alkali atom, with PHal.sub.3.

Abstract: The novel dihalomethylenelactone of formula (I) can be prepared by the trihalomethylation of an anhydride of formula (II). Reaction of compound (II), wherein R.sub.1 =R.sub.2 =methyl, with CBr.sub.3 COONa in DMF gave at -25.degree. C. the dibromovinyllactone and with CCL.sub.3 COONa in DMF at 0.degree. C. the dichlorovinyllactone. ##STR1## X.sub.1, X.sub.2 and X.sub.3 are halogen atoms and R.sub.1 and/or R.sub.2 are hydrogen atoms and/or alkyl groups with 1-10 carbon atoms;M is alkali, e.g. Na or K. The novel dihalomethylenelactones can also be prepared by treating a compound of formula (III) ##STR2## with phosphorus halide and zinc in an inert, polar aprotic solvent. The compounds are pyrethroid intermediates.

Abstract: Conversion of esters (R.sup.1)(R.sup.2)C(C Hal.sub.3)OX, X being-P Hal.sub.2, --C(O)OR.sup.3 or ##STR1## R.sup.1, R.sup.3 and R.sup.4 being optionally substituted hydrocarbyl groups and R.sup.2 methyl or hydrogen, with zinc in acetic acid gives a very high yield of a dihalovinyl compound (R.sup.1)(R.sup.2)C.dbd.C Hal.sub.2, e.g., of the ethyl ester of the parent acid of pyrethroid insecticides.

Abstract: When the reaction of aldehydes with alkali metal trihaloacetates is carried out in the presence of a highly polar aprotic solvent (DMF, DMSO), novel organic alkali metal carbonates, which are precursors of pyrethroid insecticides, are formed in high yields and at a high rate. Novel sulfonates and dihalophosphites, derived from these carbonates have also been claimed.

Abstract: Preparation of novel alkyl 2,2-dihalovinylcyclopropylacetates (intermediates in the preparation of insecticides) by reaction of a phosphine with a compound generating a dihalocarbene and reaction of the product resulting therefrom with an alkyl formylcyclopropylacetate, both reactions being carried out in a solvent.

Abstract: Isolation of cis acids of the formula ##STR1## wherein each of the groups X.sup.1 and X.sup.2 represents a fluorine, chlorine or bromine atom or a hydrocarbyl group, from a mixture of cis and trans acids of this formula, by idolactonization, forming novel cis-lactones of the formula ##STR2## isolation of these cis-lactones and reduction thereof to the said cis acids.The process may be used for the isolation of cis precursors to insecticides from mixtures with their trans isomers.

Abstract: When the reaction of aldehydes with alkali metal trihaloacetates is carried out in the presence of a highly polar aprotic solvent (DMF, DMSO), novel organic alkali metal carbonates, which are precursors of pyrethroid insecticides, are formed in high yields and at a high rate. Novel sulfonates and dihalophosphites, derived from these carbonates have also been claimed.

Abstract: 2-Formyl-3,3-dimethylcyclopropylacetic acid is prepared by ozonolysis of 3-acetyl-6,6-dimethylbicyclo[3.1.0]-2-hexene followed by reductive cleavage of the ozonolysis product thus formed. The 3-acetyl-6,6-dimethylbicyclo[3.1.0]-2-hexene is prepared by contacting 2-(2-acetyl-3-oxobutyl)-3,3-dimethylcyclopropanecarbaldehyde with a base in the presence of a solvent.

Abstract: The invention relates to 2-(2,2-dihalovinyl)-3,3-dimethylcyclopropylacetones which are intermediates for the preparation of pyrethroids which have good insecticidal properties.

Abstract: New 2-(2,2-dihalovinyl)-3,3-dimethylcyclopropane derivatives of the formula ##STR1## wherein each Hal is a halogen atom and R is dimethoxyethyl, 2-acetyl-3-oxobutyl, 2-methoxycarbonylpropyl or 2-acetyl-2-hydroxy-3-oxobutyl, are useful chemical intermediates for the preparation of pesticidally active cyclopropanecarboxylates.

Abstract: A process for the preparation of an aldehyde or a ketone by ozonolysis of an ethylenically unsaturated compound in the presence of an anti-oxidant followed by reductive cleavage of the ozonolysis product.

Abstract: .alpha.,.beta.-Unsaturated nitriles are prepared from carbonyl compounds and then reduced by reaction with an alkanol and magnesium in the presence of an ammonium salt.

Abstract: A novel process is disclosed for the preparation of cyclopropanecarbonitriles of the general formula: ##STR1## wherein R.sub.1, R.sub.2 and Hal have the meanings given in the description; which comprises heating the corresponding ammonium or aminium cyclopropanecarboxylate in the presence of a polar aprotic solvent. The process produces cyclopropanecarbonitriles, in high yields, which are useful as intermediates in the production of insecticidally active compounds.