A system and a process for dimerizing cyclopentadiene (CPD) including producing a C.sub.6+C.sub.7 rich bottoms stream and a C.sub.5 rich side draw from a debutanizer, where the C.sub.5 rich side draw and at least a portion of the C.sub.6+C.sub.7 rich bottoms stream are directed to a dimerizer where the CPD is thermally dimerized to dicyclopentadiene (DCPD). DCPD is more stable than CPD and thus safer to handle.

A compound is represented by a formula (1) below.

In the formula (1), n is 1 or 2. Ar.sup.1 is represented by a formula (2) below. Ar.sup.2 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heterocyclic group having 1 to 20 ring atoms. Ar.sup.3 is represented by a formula (3) below.

##STR00001##

The invention provides novel compounds having the general formula: ##STR00001##
and pharmaceutically acceptable salts thereof, wherein the variables R.sup.A, subscript n, ring A, X.sup.2, L, subscript m, X.sup.1, B, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.N have the meaning as described herein, and compositions containing such compounds and methods for using such compounds and compositions.

An onium salt having an anion moiety of a specific structure is an effective photoacid generator. A resist composition comprising the onium salt has the advantages of compatibility and reduced acid diffusion and forms a pattern with a good balance of sensitivity and MEF, rectangularity, and minimal defects.

A method for preparing a phenolic oligomer antioxidant with a very small residual content of butylated hydroxytoluene (BHT) is provided.

Specifically, the method for preparing the phenolic oligomer antioxidant relates to a method which is capable of a BHT-free phenolic oligomer antioxidant or a phenolic oligomer antioxidant containing a trace amount of residual BHT by removing the precursor of BHT as much as possible by performing the concentration under the reduced pressure while injecting an inert gas to an intermediate product and/or removing BHT by performing the concentration under the reduced pressure while injecting an inert gas to the final product.

A polyphenylene ether oligomer and a polyphenylene ether oligomer are provided. The polyphenylene ether oligomer has a structure represented by Formula (I):

##STR00001##

wherein each R.sup.1 can be independently hydrogen, C.sub.1-6 alkyl group, or phenyl group; each R.sup.2 can be independently hydrogen, C.sub.1-6 alkyl group, or phenyl group; a:(a+b) is from 0.05:1 to 1:1; n:(a+b) is from 0.05:1 to 5:1; Q can be

##STR00002##

m can be 0 or an integer from 1 to 4; Ra can be C.sub.1-6 alkylene group; Rb can be C.sub.1-6 alkylene group; each X is independently hydrogen, acryloyl group, allyl group, vinylbenzyl group, epoxypropyl group, methacryloyl group, propargyl group, or cyanol group; and wherein the polyphenylene ether oligomer can have a number average molecular weight from 400 to 2,000.

A resist composition which generates acid upon exposure and exhibits changed solubility in a developing solution under action of acid, and which includes a base component which exhibits changed solubility in a developing solution under action of acid and an acid-generator component including a compound (B0-1) represented by general formula (b0) shown below in which Ra.sup.1 represents an aromatic ring; Ra.sup.01 represents an alkyl group of 5 or more carbon atoms optionally having a substituent; Ra.sup.02 and Ra.sup.03 each independently represents an alkyl group of 1 to 10 carbon atoms optionally having a substituent; n1 represents an integer of 1 to 5; n2 represents an integer of 0 to 2; n3 represents an integer of 0 to 4; and X.sup. represents a counteranion. ##STR00001##

High heat monomer compounds, methods for preparing compounds, and compositions derived from the compounds are provided. Also provided are materials and articles derived from the compounds.

A process for inhibiting the polymerization of cyclopentadiene compounds (B) by contacting the cyclopentadiene compound with a quinone methide compound (A) of structure (I), ##STR00001##
Compositions (AB) comprising (A) and (B) are also provided.

The present invention relates to bi- and tricyclic compounds of the general formula (I) (I) wherein the dashed lines independently of each other represent a single or a double bond, X represents a group of the formulae X.sub.1 to X.sub.3 wherein the asterisk denotes the point of attachment to the rest of the molecule, R.sup.1a and R.sup.1b, independently of each other, are selected from hydrogen or methyl, or R.sup.1a together with R.sup.1b form a methylene or ethylene group, R.sup.2, R.sup.3a, R.sup.3b, R.sup.4, R.sup.5a and R.sup.5b, independently of each other, are selected from hydrogen or methyl, R.sup.6 is selected from hydrogen, methyl or ethyl, and R.sup.7 is methyl or ethyl, to a method of preparing said compounds, to the use of a bi- or tricyclic compounds or of mixtures of two or more bi- and tricyclic compounds or of a stereoisomer thereof or of a mixture of two or more stereoisomers thereof as aroma chemicals; to the use of a bi- or tricyclic compound for modifying the scent character of a fragranced composition; to an aroma chemical composition containing a bi- or tricyclic compound or a mixture of two or more bi- and tricyclic compounds or of a stereoisomer thereof or of a mixture of two or more stereoisomers thereof; and to a method of preparing a fragranced composition or for modifying the scent character of a fragranced composition, comprising incorporating a bi- or tricyclic compound or a mixture of two or more bi- and tricyclic compounds or of a stereoisomer thereof or of a mixture of two or more stereoisomers thereof into said composition. ##STR00001##