An extraction solvent comprised of one or more ethyleneamines having structure (I), (II), or (III):

##STR00001##

where R.sub.1-R.sub.6 can independently be H, C.sub.1-C.sub.4 linear or branched alkyl, amido (RRNCO), or hydroxyalkyl, where each R in the amido group independently H or C.sub.1 alkyl, and where x ranges from 1 to 6, may be contacted with a hydrocarbon stream to remove or extract non-acidic contaminants, such as thiophenes, benzothiophenes, alkyl sulfides, alkyl disulfides, mercaptans, aromatics, oxygenates, metals, olefins, and combinations thereof, from the hydrocarbon stream. The extraction solvent may include co-solvents and the hydrocarbon stream may be in gas and/or liquid form.

The embodiments provide an acidic gas absorbent, an acidic gas removal method using the absorbent, and an acidic gas removal apparatus using the absorbent. The absorbent absorbs an acidic gas in a large amount and is hardly diffused. The acidic gas absorbent according to the embodiment comprises an amine compound represented by the following formula (1):

##STR00001##

[In the formula, each R.sup.1 is independently hydrogen, an alkyl group, or a primary or secondary amino-containing aminoalkyl group provided that at least one of R.sup.1s is the aminoalkyl group, each R.sup.2 is independently hydrogen, an alkyl group, hydroxy, amino, hydroxyamino, or a primary or secondary amino-containing aminoalkyl group, the alkyl or aminoalkyl group contained in R.sup.1 or R.sup.2 has a straight-chain or branched-chain skeleton and may be substituted with hydroxy or carbonyl, and p is 2 to 4.]

The invention relates to a process for dehumidifying a moist gas mixture. The invention further relates to an apparatus for dehumidifying a moist gas mixture and to the use of said apparatus in the process according to the invention.

The invention relates to a process for dehumidifying a moist gas mixture and to the absorption medium used in the process. The invention further relates to an apparatus for dehumidifying a moist gas mixture and to the use of said apparatus in the process according to the invention.

An aqueous solvent composition is provided, comprising a nucleophilic component having one or more sterically unhindered primary or secondary amine moieties, a Brnsted base component having one or more basic nitrogen moieties, a water-soluble organic solvent, and water. A biphasic composition is provided, comprising one or more carbamate compounds, one or more conjugate acids of Brnsted base, a water-soluble organic solvent, and water. A biphasic CO.sub.2 absorption process is also provided, utilizing the biphasic solvent composition.

A process for absorbing carbon dioxide from a gas stream containing carbon dioxide, including contacting the gas stream with an aqueous composition having a substituted heteroaromatic compound including a six-membered heteroaromatic ring comprising from 1 to 3 nitrogen atoms in the heteroaromatic ring and at least one substituent wherein at least one of the substituents is of formula R.sup.1NH.sub.2 wherein R.sup.1 is selected from C.sub.1 to C.sub.6 alkylene and ethers of formula R.sup.2OR.sup.3 wherein R.sup.2 and R.sup.3 are C.sub.1 to C.sub.3 alkylene.

Systems comprising a composition where an imidazole is tethered to an amine and a solvent are described herein. Methods of their preparation and use are also described herein. The methods of using the systems include the reduction of volatile compounds from gas streams and liquid stream.

A process for absorbing carbon dioxide from a gas stream containing carbon dioxide, including the steps of contacting the gas stream with an aqueous composition including a substituted heteroaromatic compound having a six-membered heteroaromatic ring with from 1 to 3 nitrogen atoms in the heteroaromatic ring and at least one substituent wherein at least one of the substituents is of formula R.sup.1NH.sub.2 wherein R.sup.1 is selected from C.sub.1 to C.sub.6 alkylene and ethers of formula R.sup.2OR.sup.3 wherein R.sup.2 and R.sup.3 are C.sub.1 to C.sub.3 alkylene.

A filter for binding constituents of a gas stream includes a supporting member and a filter layer applied to surfaces of the supporting member. The filter layer includes a component for the physisorption of constituents, a component for the chemisorption of constituents, and a component for dissolving oil constituents which comprises ionic liquids.

The present invention relates to a dehydration composition and method of use thereof for drying gas streams, in particular natural gas streams, wherein the dehydration composition comprises (i) a glycol, (ii) an imidazole compound, and optionally (iii) one or more of an alkali metal carboxylate, an additional glycol different than (i), an alkanolamine, a phosphate acid, a salt of a phosphate acid, a borate acid, a salt of a borate acid, a sweetening agent, a low temperature viscosity improver, a corrosion inhibitor, an antifoaming agent, or mixtures thereof.