reference will now be made in detail to representative embodiments of the invention . while the invention will be described in conjunction with the enumerated embodiments , it will be understood that they are not intended to limit the invention to those embodiments . on the contrary , the invention is intended to cover all alternatives , modifications , and equivalents that may be included within the scope of the present invention as defined by the claims . one skilled in the art will recognize many methods and materials similar or equivalent to those described herein , which could be used in and are within the scope of the practice of the present invention . the present invention is in no way limited to the methods , materials , and compositions described . unless defined otherwise herein , technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs . although any methods , devices , and materials similar or equivalent to those described herein can be used in the practice or testing of the invention , the preferred methods , devices and materials are now described . compounds of formulas i and ii can be formed by the reductive alkylation of a compound such as bis ( 2 -( piperazin - 1 - yl ) ethyl ) amine ( bpea ). the preparation of bpea and other cyclic amines having a bis - piperazinyl - amine structure is described in commonly assigned u . s . provisional patent application ser . no . 61 / 581 , 323 entitled formation of higher molecular weight cyclic polyamine compounds from cyclic polyamine compounds , filed dec . 29 , 2011 ( king ). a compound of formula i or ii can be prepared by the reductive alkylation of a compound of formula iii or iv , as shown below . in formula iii : r 2 , r 2 ′ , r 3 , r 3 ′ , r 4 , and r 4 ′ , independently selected from hydrogen , — ch 3 , and — ch 2 ch 3 ; and x and x ′ are independently 0 ( a covalent bond ) or 1 . examples of cyclic amines of formula iii that can be reductively alkylated include bis ( 2 -( piperazin - 1 - yl ) ethyl ) amine ( bpea ), bis ( 3 -( piperazin - 1 - yl ) propyl ) amine , bis ( 1 -( piperazin - 1 - yl ) propan - 2 - yl ) amine , and bis ( 2 -( piperazin - 1 - yl ) propyl ) amine . examples of cyclic amines of formula iv that can be reductively alkylated include 2 -( 4 -( 2 -( piperazin - 1 - yl ) ethyl ) piperazin - 1 - yl ) ethanamine , 3 -( 4 -( 3 -( piperazin - 1 - yl ) propyl ) piperazin - 1 - yl ) propan - 1 - amine , 1 -( 4 -( 1 -( piperazin - 1 - yl ) propan - 2 - yl ) piperazin - 1 - yl ) propan - 2 - amine , and 2 -( 4 -( 2 -( piperazin - 1 - yl ) propyl ) piperazin - 1 - yl ) propan - 1 - amine . reductive alkylation is an effective method to synthesize secondary and tertiary amines from primary and secondary amines using aldehydes and ketones . reductive alkylation can be carried out by reacting a compound of formula iii or iv with a c1 - c8 aldehyde or a c3 - c8 ketone in the presence of a reducing agent . exemplary aldehydes include formaldehyde , acetaldehyde , propionaldehyde , butyraldehyde , and 2 - ethylhexanal . exemplary ketones include acetone , 2 - butanone , 3 - pentanone , and methyl isobutyl ketone . the reaction can be carried out with a desired amount of a compound of formula iii or iv and an aldehyde or a ketone to provide a partially or fully alkylated product ( formula i or ii ). partial alkylation can be carried out using less than the molar equivalents of the ketone or aldehyde relative to the molar equivalents of nitrogen on a compound of formula iii or iv ( e . g ., 2 molar equivalents , or 1 molar equivalent for 3 nh functionalities ). full alkylation can be carried out using an equimolar number of equivalents , or greater , of the ketone or aldehyde relative to the equivalents of nh functionality . reductive alkylation can be carried out in the presence of hydrogen and a hydrogenation catalyst , such as a nickel - based catalyst , at elevated temperatures , and in a suitable solvent , such as methanol . partial or full reductive alkylation can provide a cyclic amine compound of formula i : in formula i or ii , r 1 , r 1 ′ , and r 1 ″ are independently selected from hydrogen and c1 - c8 hydrocarbyl groups , wherein at least one of r 1 , r 1 ′ , or r 1 ″ is a c1 - c8 hydrocarbyl group . r 2 , r 2 ′ , r 3 , r 3 ′ , r 4 , and r 4 ′ are independently selected from hydrogen , — ch 3 , and — ch 2 ch 3 . also in formula i or ii x and x ′ are independently 0 ( a covalent bond ) or 1 . hydrocarbyl groups as referred to herein are substituted or unsubstituted , linear , branched , or cyclic hydrocarbyl groups , such as alkyl , aryl , aralkyl , or the like . more specifically , in some cases , in formula i or ii , at least one of r 1 , r 1 ′ , or r 1 ″ is a c1 - c3 hydrocarbyl group . for example , if one or two of r 1 , r 1 ′ , and / or r 1 ″ is / are a c1 - c3 hydrocarbyl group ( s ), the non - c1 - c3 hydrocarbyl group ( s ) of r 1 , r 1 ′ , and / or r 1 ″ can be hydrogen . in this case the compound of formula i or ii can be partially alkylated . in other cases in formula i or ii , all r 1 , r 1 ′ , and groups are independently selected from c1 - c3 hydrocarbyl groups , which can be the same of different . in this case the compound of formula i or ii can be fully alkylated . in some cases of full alkylation , all of r 1 , r 1 ′ , and r 1 ″ are independently selected from — ch 3 , — ch 2 ch 3 , — ch 2 ch 2 ch 3 , — ch ( ch 3 ) 2 , — ch 2 ch 2 ch 2 ch 3 , — ch 2 ch ( ch 2 ch 3 ) ch 2 ch 2 ch 2 ch 3 , and — ch ( ch 3 ) ch 2 ch ( ch 3 ) 2 . in more specific cases of full alkylation , all of r 1 , r 1 ′ , and r 1 ″ are — ch 3 . included as chemical species in the compounds of formula i and ii are n - methyl - 2 -( 4 - methylpiperazin - 1 - yl )- n -( 2 -( 4 - methylpiperazin - 1 - yl ) ethyl ) ethanamine ( methyl - bpea ; mebpea ), n - ethyl - 2 -( 4 - ethylpiperazin - 1 - yl )- n -( 2 -( 4 - ethylpiperazin - 1 - yl ) ethyl ) ethanamine ( ethyl - bpea ; ebpea ), n , n - bis ( 2 -( 4 - isopropylpiperazin - 1 - yl ) ethyl ) propan - 2 - amine ( isopropyl - bpea ; ibpea ), and 2 - ethyl - n , n - bis ( 2 -( 4 -( 2 - ethylhexyl ) piperazin - 1 - yl ) ethyl ) hexan - 1 - amine ( 2 - ethylhexyl - bpea ; 2 - ebpea ), n , n - dimethyl - 2 -( 4 -( 2 -( 4 - methylpiperazin - 1 - yl ) ethyl ) piperazin - 1 - yl ) ethanamine , n , n - diethyl - 2 -( 4 -( 2 -( 4 - ethylpiperazin - 1 - yl ) ethyl ) piperazin - 1 - yl ) ethanamine , n - isopropyl - n -( 2 -( 4 -( 2 -( 4 - isopropylpiperazin - 1 - yl ) ethyl ) piperazin - 1 - yl ) ethyl ) propan - 2 - amine , and 2 - ethyl - n -( 2 - ethylhexyl )- n -( 2 -( 4 -( 2 -( 4 -( 2 - ethylhexyl ) piperazin - 1 - yl ) ethyl ) piperazin - 1 - yl ) ethyl ) hexan - 1 - amine . in some embodiments , the invention provides cyclic amine derivatives of formula i or ii where any one or more of the nitrogen ( s ) in the cyclic amine derivative carry a positive charge and are electrostatically blocked by an acid anion . such acid blocked cyclic amine derivatives can be formed by protonating any one or more of the nitrogen atom ( s ) of compounds of formula i and ii , thereby creating quaternary ammonium cation ( s ), which are electrostatically blocked by the anionic group of an acid ( s ). as used herein , a “ derivative ” refers to an acid - blocked species of formula i and ii . an exemplary process for acid blocking involves mixing a non - acid blocked compound of formula i or ii with a desired acid , or combination of acids , in solution . solvents that can be used include water , ethylene glycol , diethylene glycol , dipropylene glycol , or butanediol , or mixtures thereof . an exemplary catalyst amount is at weight ratio in the range of 10 - 80 % in the solvent . the non - acid blocked compound of formula i or ii is mixed with the acid to provide a ph value of 7 . 0 or higher in an aqueous solution . techniques for acid blocking using a dicarboxylic acid are described in ep0989146 ( kometani , et . al ). exemplary acid blocking compounds include anions of saturated dicarboxylic acids such as succinic acid , glutaric acid , adipic acid , pimelic acid , suberic acid , azelaic acid , sebacic acid , undecanedioic acid , decane - dicarboxylic acid , 1 , 11 - undecane - dicarboxylic acid , 1 , 12 - dodecane - dicarboxylic acid , and hexadecanedioic acid . exemplary acid blocking compounds also include anions of saturated monocarboxylic acids such as acetic acid , propionic acid , butyric acid , valeric acid , caproic acid , caprylic acid , caproic acid , 2 - ethylhexanoic acid , and 2 - cyanoacetic acid . exemplary acid blocking compounds can also be obtained from the ring opening of fatty acid anhydrides . the extent of acid blocking can be determined from factors such as the chemical structure of a compound of formula i or ii , and the amount and type of acid reagent used for blocking . the acid blocked cyclic amine derivatives can include partially blocked cyclic amine derivatives and fully blocked cyclic amine derivatives . a monoacid which has one anionic group will be able to block one cationic group of a protonated amine , whereas a diacid having two anionic groups will be able to block two cationic group ( s ), such as on the same or on different cyclic amine compounds . exemplary acid blocked cyclic amine derivatives showing acid blockage at the protonated amines of r 1 — n , r 1 ′ — n , or r 1 ″ — n include those of formula v : in formula v , r 1 , r 1 ′ , and r 1 ″ are independently selected from hydrogen and c2 - c8 hydrocarbyl groups . optionally , at least one or more of r 1 , r 1 ′ , and r 1 ″ is a c1 - c8 hydrocarbyl group . in formula v , r 2 , r 2 ′ , r 3 , r 3 ′ , r 4 , and r 4 ′ are independently selected from hydrogen , — ch 3 , and — ch 2 ch 3 . also in formula v x and x ′ are independently 0 ( a covalent bond ) or 1 . a , a ′, and a ″ are independently selected from — r 5 r 6 , where r 5 is a linear , branched , or cyclic c2 - c14 hydrocarbylene group , and r6 is — h or — c ( o ) o − . for full blocking of the protonated amines as illustrated , formula v shows a 1 : 3 molar ratio of cyclic amine to acid , when the acid blocking compound is a monocarboxylic acid . however , if the acid blocking compound is a dicarboxylic acid , the molar ratio of cyclic amine to acid is 2 : 3 for full blocking ( the other cyclic amine is not shown ). prior to inclusion in a composition , such as a polyurethane foam - forming composition , the compound of formula i or ii can be separated ( refined ) by any method known in the art . methods for purification or separation include conventional distillation technology using dividing wall columns , membrane separation , melt crystallization , and reactive distillation . compounds of formula i or ii can be used in “ neat ” form , as , for example , a liquid , with no solvent present . for example , n - methyl - 2 -( 4 - methylpiperazin - 1 - yl )- n -( 2 -( 4 - methylpiperazin - 1 - yl ) ethyl ) ethanamine ( methyl - bpea ; mebpea ) is a liquid at room temperature (˜ 25 ° c . ), and has a boiling point ( 760 torr ) of ˜ 338 ° c . alternatively , the compounds of formula i or ii can be used along with a solvent , or combination of solvents . desirably , the solvent is not unduly reactive with the cyclic amine product of formula i or ii . some examples of solvents that could be in mixture with the cyclic amine include saturated hydrocarbons such as pentane , hexane , octane , nonane , decane , or the like ; aromatic hydrocarbons such as toluene , benzene , xylene , ether , combinations of these , and the like . cyclic amine compounds of formula i or ii can also be described in terms of the molecular weight . exemplary cyclic amine compounds of formula i or ii have a molecular weight in the range of about 255 da to about 690 da , about 269 da to about 600 da , or about 283 da to about 578 da . a compound of formula i or ii , an acid blocked cyclic amine derivative thereof , or a mixture of compounds of formula i or ii or acid blocked derivatives thereof , can be present in a composition with components used for making foams . for example , other aspects of the invention are directed to compositions for making polyurethane foams , methods for making polyurethane foams , and polyurethane foams made using a cyclic amine of formula i or ii , or an acid blocked derivative thereof . in some modes of practice , a cyclic amine compound of formula i or ii or an acid blocked derivative thereof can be used in a composition to provide catalytic activity during the foam forming reaction . included in the composition along with ( a ) the cyclic amine or acid - blocked derivative are ( b ) a polyol compound , and ( c ) a polyisocyanate . cyclic amine compounds of formula i or ii , or acid blocked derivates thereof , can be used in a composition at a desired concentration to provide catalytic activity during the foam forming reaction . exemplary concentrations of the cyclic amine compound of formula i or ii , or acid blocked derivate thereof , may be different for flexible or rigid foams . for flexible foams , exemplary concentrations of the cyclic amine or derivative thereof are in the range of about 0 . 02 wt . % to about 1 . 5 wt . %, 0 . 05 wt . % to about 1 wt . %, or 0 . 1 wt . % to about 0 . 8 wt . % by weight of the polyol . for rigid foams , exemplary concentrations of the cyclic amine or derivative are in the range of about 0 . 1 wt . % to about 3 wt . %, 0 . 2 wt . % to about 2 wt . %, or 0 . 5 wt . % to about 1 . 5 wt . % by weight of the polyol . one or more catalysts that are different than the cyclic amine of formula i or ii , or acid blocked derivate thereof , may optionally be used in the composition along with the cyclic amine or derivative . exemplary gelling catalysts that can optionally be used in combination with the cyclic amine or derivative thereof include , but are not limited to , n , n - bis ( 3 - dimethylamino - propyl ) n - isopropanol - amine ; n , n - dimethylaminoethyl - n ′- methyl ethanolamine ; n , n , n ′- trimethylaminopropyl ethanolamine ; n , n - dimethylethanolamine ; n , n - dimethyl - n ′, n ′- 2 - hydroxy ( propyl )- 1 , 3 - propylenediamine ; dimethylaminopropylamine ; ( n , n - dimethylaminoethoxy ) ethanol ; methylhydroxyethylpiperazine , bis ( n , n - dimethyl - 3 - aminopropyl ) amine ; n , n - dimethyl - aminopropyl urea ; n , n ′- bis ( 3 - dimethylaminopropyl ); bis ( dimethylamino )- 2 - propanol ; n -( 3 - aminopropyl ) imidazole ; n -( 2 - hydroxypropyl ) imidazole ; and n -( 2 - hydroxyethyl ) imidazole . the type and amount of optional gelling catalyst can be chosen based on the factors such as the components in the foam - forming composition and desired properties of the formed foam . exemplary blowing catalysts that can optionally be used in combination with the cyclic amine or derivative thereof include non - fugitive blowing catalysts include , but are not limited to , 2 [ n -( dimethylaminoethoxy - ethyl )- n - methylamino ] ethanol ; dimethylaminoethoxy - ethanol ; n , n , n ′- trimethyl - n ′- 3 - amino - propyl - bis ( aminoethyl ) ether ; and n , n , n ′- trimethyl - n ′- aminopropyl - bis ( aminoethyl ) ether . the type and amount of optional blowing catalyst can be chosen based on the factors such as the components in the foam - forming composition and desired properties of the formed foam . exemplary polyols that can be used to produce polyurethane materials with the cyclic amine catalysts of formula i or ii , include those that are well known in the art . these include polyols described herein , commercially available polyol , and polyols described in the literature . general classes of polyols that can be used in the polyurethane foam forming composition include polyether polyols , polyester polyols , polyhydroxy - terminated acetal resins , hydroxyl - terminated amines , and polyamines ( see , for example , u . s . pat . no . 4 , 394 , 491 ). other polyols classes include polyalkylene carbonate - based polyols and polyphosphate - based polyols . copolymer polyols , some of which can be prepared by grafting methodologies , include styrene / acrylonitrile ( san ) copolymer polyols , polyisocyanate poly addition ( pipa ) polyols , and polyharnstoff dispersion ( phd ) copolymer polyols . copolymer polyols can include polymer segments other than the polyol portion to introduce desirable properties into the copolymer polyol , such as hardness . exemplary polyols are also described in the polyurethane handbook ( g . oertel , hanser publishers ). the polyurethane foam forming composition can optionally include mixtures of one or more different polyol types , such as mixtures of two different polyols selected from polyol homopolymers and polyol copolymers . exemplary polyols that can be used in the foam - forming composition include alkylene oxide - based polyols prepared from polyol - generating monomers such as ethylene oxide , propylene oxide , butylene oxide , or combinations thereof . alkylene oxide - based polyols can be made from monomer initiators with active hydrogen atoms , such as those having two or more hydroxyl or amine groups . in some polyol preparations , monomer initiators have from 2 to 8 , or more specifically 2 to 6 active hydrogen atoms . exemplary monomer initiators include organic dicarboxylic acids , such as succinic acid , adipic acid , phthalic acid and terephthalic acid and polyhydric alcohols , in particular dihydric to octahydric alcohols or dialkylene glycols , for example , ethanediol , 1 , 2 - and 1 , 3 - propanediol , diethylene glycol , dipropylene glycol , 1 , 4 - butanediol , 1 , 6 - hexanediol , glycerol , trimethylolpropane , pentaerythritol , sorbitol , and sucrose , or blends thereof . other initiators include linear and cyclic compounds containing an amine such as n - methyldiethanolamine , triethanolamine , and various isomers of toluene diamine . the particular polyol or polyol mixture , and polyol amount used in the polyurethane foam forming composition can be chosen based on the factors such as the desired polyurethane foam properties and / or the particular end use of the foam product . properties of the polyol such as molecular weight or hydroxyl number can be chosen to provide foam characteristics selected from : low density , high density , conventional , high resilient , hot molding , cold molding , flexible , and rigid , and desired combinations thereof . for many applications or foam properties , the hydroxyl number of the polyol is in the range of about 15 to about 800 , with a preferred hydroxyl number for flexible foams in the range of about 20 to about 60 , and a preferred hydroxyl number for flexible foams in the range of about 200 to about 800 . compositions for the production of flexible polyurethane foams typically include a polyether polyol and / or a polyester polyol . the polyol generally has an average functionality ranging from 2 to 5 , preferably 2 to 4 , and an average hydroxyl number ranging from 20 to 100 mg koh / g , preferably from 20 to 70 mg koh / g ( see , for example , u . s . pat . no . 7 , 361 , 695 ). for flexible foams , the hydroxyl number of the base polyol can be in the range of about 20 to about 60 with ethylene oxide ( eo ) capping , and for slabstock foams the hydroxyl number can be in the range of about 25 to about 75 ( see , for example , u . s . pat . no . 7 , 361 , 695 ). polyurethane foam - forming compositions also include a polyisocyanate , such as a polyisocyanate selected from aliphatic , cycloaliphatic , arylaliphatic , and aromatic polyisocyanates . aromatic polyisocyanates are preferred for the production of flexible foams . exemplary polyisocyanates include the 4 , 4 ′-, 2 , 4 ′ and 2 , 2 ′- isomers of diphenylmethane diisocyante ( mdi ), blends thereof ; polymeric and monomeric mdi blends ; toluene - 2 , 4 - and 2 , 6 - diisocyanates ( tdi ), blends thereof ; biuret modified tdis , tdi / mdi blends ; polymerized isocyanates , m - and p - phenylenediisocyanate , chlorophenylene - 2 , 4 - diisocyanate , diphenylene - 4 , 4 ′- diisocyanate , 4 , 4 ′- diisocyanate - 3 , 3 ′- dimethyldiphenyl , 3 - methyldiphenyl - methane - 4 , 4 ′- diisocyanate , diphenyletherdiisocyanate , 2 , 4 , 6 - triisocyanatotoluene , and 2 , 4 , 4 ′- triisocyanatodiphenylether ( see , for example , u . s . pat . no . 7 , 361 , 695 ). examples of aliphatic polyisocyanates include ethylene diisocyanate , 1 , 6 - hexamethylene diisocyanate , isophorone diisocyanate , cyclohexane 1 , 4 - diisocyanate , 4 , 4 ′- dicyclohexylmethane diisocyanate , saturated analogues of the above mentioned aromatic isocyanates , and mixtures thereof . isocyanate - terminated prepolymers are prepared by reacting an excess of polyisocyanate with polyols , including aminated polyols or imines / enamines thereof , or polyamines ( see , for example , u . s . pat . no . 7 , 361 , 695 ). for some foam products such as flexible polyurethane foams , water can optionally be used as a blowing agent . exemplary amounts of water are in the range of about 0 . 5 to about 10 parts by weight , or more specifically in the range of about 1 to about 6 parts by weight based on 100 parts by weight of the polyol . carboxylic acids or salts can also optionally be used as blowing agents . use of carbon dioxide , either as a gas or as a liquid , as auxiliary blowing agent , in addition to water can optionally be used . during foam formation , atmospheric pressure can be adjusted , frothing can be used , or combinations thereof , as described in u . s . pat . no . 5 , 194 , 453 to vary foam density . for the preparation of some thermally insulating polymeric foams , a low - conductivity gas such as a hydrochlorofluorocarbon ( hcfc ) or a hydrofluorocarbon ( hfc ) can be used as a blowing agent . polyurethane insulating foams can be prepared using hcfcs or hfcs to provide polyurethane closed - cell foam insulation materials . the high thermal resistance of the hcfcs or hfcs can provide polyurethane insulation with r - values generally in the range of about r - 6 to about r - 8 per inch . r - values are a measure of thermal resistance being a ratio of the temperature difference across an insulator and the heat flux ( heat transfer per unit area ) through it . a “ hydrochlorofluorocarbon ” ( hcfc ) refers to a compound having carbon , hydrogen , chlorine , and fluorine atoms ; a “ hydrofluorocarbon ” ( hfc ) refers to a carbon compound having carbon , hydrogen , and fluorine groups . typical hcfcs and hfcs are derived from methane , ethane , propane , and butane . exemplary hydrofluorochlorocarbons and hydrofluorocarbons are selected from the group consisting of chlorodifluoromethane ; 1 - chloro - 1 , 1 - difluoroethane ; 1 , 1 - difluoroethane ; 1 , 2 - difluoroethane ; 1 , 1 , 1 , 2 - tetrafluoroethane ; 2 , 2 - dichloro - 1 , 1 , 1 - trifluoroethane ; 1 , 2 , 2 - trifluoroethane ; 1 , 1 , 1 , 2 , 3 , 3 , 3 - heptafluoropropane ; 1 , 1 , 1 , 3 , 3 - pentafluoropropane ; 1 , 2 - dichloro - 3 , 3 , 3 - trifluoropropene ; 1 - chloro - 1 , 3 , 3 , 3 - tetrafluoropropane ; 1 - chloro - 3 , 3 , 3 trifluoropropene ; cis - 1 , 3 , 3 , 3 - tetrafluoropropene ; 1 , 2 , 2 , 3 , 3 - pentafluoropropane ; 1 , 1 , 1 , 3 , 3 - pentafluorobutane ; and 1 , 1 , 2 , 2 - tetrafluoroethyl methyl ether . in some preparations , the amount of the hcfc and hfc blowing agent is in the range of about 1 to about 40 parts by weight , about 4 to about 35 parts by weight , or more specifically about 6 to about 30 parts by weight based on 100 parts by weight of the polyol . mixtures of blowing agents can also be used . for example , the blowing agent can comprise a mixture of two or more hcfc and / or hfc blowing agents , or the mixture can comprise a mixture of one or more hcfc or hfc blowing agents and a non - halogenated hydrocarbon blowing agent such butane , pentane , or cyclopentane . other components can be used in addition to the cyclic amine of formula i or ii , or acid blocked derivative thereof and the foam - forming reagents ( polyol and polyisocyanate components ). these other components include , but are not limited to surfactants , preservatives , flame retardants , colorants , antioxidants , reinforcing agents , stabilizers , and fillers . in making polyurethane foam , it is generally preferred to employ an amount of a surfactant to stabilize the foaming reaction mixture until it cures . in some formulations , the composition includes a liquid or solid organosilicone surfactant . other surfactants include polyethylene glycol ethers of long - chain alcohols , tertiary amine or alkanolamine salts of long - chain alkyl acid sulfate esters , alkyl sulfonic esters , and alkyl arylsulfonic acids . surfactants can be used in amounts sufficient to stabilize the foaming reaction mixture against collapse and the formation of a desired cell structure . exemplary amounts of surfactant are in the range of about 0 . 2 to about 3 parts of the surfactant per 100 parts by weight total polyol . mixtures of surfactants can be used . in some formulations , the composition can include an organometallic catalyst to promote the reaction of the polyol with the polyisocyanate . exemplary organometallic catalysts include organomercury , organolead , organoferric and organotin catalysts . exemplary tin catalysts include stannous chloride , tin salts of carboxylic acids such as dibutyltin di - laurate , as well as other organometallic compounds such as disclosed in u . s . pat . no . 2 , 846 , 408 . a catalyst for the trimerization of polyisocyanates , resulting in a polyisocyanurate , such as an alkali metal alkoxide may also optionally be used in the foam forming compositions . exemplary amounts of optional organometallic catalysts range from about 0 . 001 to about 1 percent in the composition . other components that can optionally be added to the foam forming composition include crosslinking agents and chain extenders . exemplary crosslinking agents and chain extenders include low - molecular polyhydric alcohols such as ethylene glycol , diethylene glycol , 1 , 4 - butanediol , and glycerin ; low - molecular weight amine polyols such as diethanolamine and triethanolamine ; diamines such as ethylenediamine , xylenediamine ; and methylene - bis ( o - chloroaniline ). the use of such crosslinking agents or chain extenders is known in the art as disclosed in u . s . pat . nos . 4 , 863 , 979 and 4 , 963 , 399 , and ep 549 , 120 . in some modes of practice , a polyurethane foam forming composition including ( a ) a compound of formula i or ii , or an acid - blocked derivative thereof ; ( b ) a hcfc or hfc ; ( c ) a polyol ; and ( d ) a polyisocyanate is used for a sprayed or foamed - in - place application . low - density foams formed using a composition including these components can be sprayed into a desired area and rapidly expanded to seal and fill the cavity . exemplary uses of sprayed or foamed - in - place compositions include residential and commercial building insulation . foams produced using a compound of formula i or ii , or an acid - blocked derivative thereof , can be used in applications known in the industry . for example , flexible foams find use in applications such as vehicle parts , such as seats , armrests , dashboards or instrument panels , sun visors , door linings , noise insulation parts either under the carpet or in other parts of the car interior or in the engine compartment , as well as in many domestic applications such as shoe soles , cloth interliners , appliance , furniture and bedding . processes for producing polyurethane products are well known in the art . in general components of the polyurethane - forming reaction mixture can be mixed together in any convenient manner , for example by using any of the mixing equipment described in the prior art for the purpose such as described in polyurethane handbook , by g . oertel , hanser publisher . the polyurethane products are either produced continuously or discontinuously , by injection , pouring , spraying , casting , calendering , etc . the foams can be made under free rise or molded conditions , at atmospheric pressure , reduced or increased air pressure , with or without release agents , in - mold coating , or any inserts or skin put in the mold . flexible molded foams can be mono - or dual - hardness . the polyurethane foams can optionally be described by one or more foam properties , including , but not limited to : airflow , density , indentation force deflection ( ifd ), sag factor , recovery ratio , guide factor , compression load deflection ( cld ), percent (%) compression set , tensile strength , elongation , tear , permeability , impact resilience , and thickness . density is weight per unit volume ( weight / volume ) and typically expressed as lbs / ft3 ( pcf ) or g / l . exemplary foam densities are in the range of about 0 . 4 lbs / ft 3 to about 50 lbs / ft 3 , about 0 . 5 lbs / ft 3 to about 30 lbs / ft 3 , about 1 lbs / ft 3 to about 10 lbs / ft 3 , about 1 . 5 lbs / ft 3 to about 5 lbs / ft 3 , or more specifically in the range of about 1 . 75 lbs / ft 3 to about 3 lbs / ft 3 . compression force deflection ( cfd ), such as measured by the iso 3386 / 1 standard , is a testing standard designed to measure the compression stress / strain ( load divided by specimen surface area at a certain compression percentage ) characteristic of foam . cfd is also a measure of firmness and is expressed in kilopascals ( kpa ) or pounds per square inch ( psi ), at a given percentage deflection . foam compositions can be prepared to provide foam with a desired cfd , or a cfd within a desired range . percent compression set ( cs ), such as measured by the iso 1856 standard , is a measure of the permanent deformation of foam after it has been compressed between two metal plates for a controlled time period and temperature condition . the standard conditions are 22 hours at 70 ° c . ( 158 ° f .). exemplary compression set values are less than 20 %, less than 10 %, or more specifically less than 5 %. tensile strength is a measure of the amount of force required to break an area of foam as it is pulled apart , and is generally expressed in pounds per square inch ( psi ). exemplary tensile strength values are greater than about 10 psi or more specifically greater than about 14 psi . impact resilience ( ball rebound ), such as measured by the astm d - 3574 - h standard , is a measure of elasticity , bounce , or springiness of foam and is expressed as a % of return , or % resilience . foam compositions can be prepared to provide a foam with a desired resilience , or a resilience within a desired range . 27 . 3 grams ( 0 . 11 mol ) of bis ( 2 -( piperazin - 1 - yl ) ethyl ) amine ( bpea ) dissolved in 80 ml of methanol was charged to a 300 ml 3 - neck flask . with stirring under nitrogen , 23 . 7 grams ( 0 . 43 mol ) of methyl formal ( 55 % formaldehyde ) was added slowly with cooling to the flask while maintaining a temperature of & lt ; 40 ° c . to give a light yellow colored solution . the material was diluted with an additional 100 ml of methanol and charged to a pressure reactor which contained 10 . 1 grams of raney ® ni grade r3111 ( grace davison ) catalyst which had been washed three times with methanol . the reactor was purged and evacuated three times with nitrogen , followed by three times with hydrogen . hydrogen was added to the reactor at room temperature to an initial pressure of ca . 500 psig . for one hour additional hydrogen was added to maintain a reactor pressure of 360 - 580 psig . the reactor was then heated to 70 ° c . and held at that temperature for ca . 2 . 5 hours . the reactor was cooled , the contents filtered via vacuum and the filtrate concentrated on a rotovap to give 31 grams ( 100 %) of n - methyl - 2 -( 4 - methylpiperazin - 1 - yl )- n -( 2 -( 4 - methylpiperazin - 1 - yl ) ethyl ) ethanamine ( methylated bpea ) as a yellow oil . foams of examples 2 - 4 were made in the laboratory on the bench by pre - blending polyols , surfactant , catalysts , and water of the types and amounts according to table 1 . the pre - blends were conditioned at 25 ° c . isocyanate , also conditioned at 25 ° c ., was added to the pre - blends under stirring at 2800 rpm for 5 seconds . at the end of mixing the reactants were poured into a 30 × 30 × 10 cm aluminum mold heated at 50 ° c . which was subsequently closed . prior to use , the mold was sprayed with a release agent . after 6 minutes the cured foam part was manually demolded and allowed to sit for 7 days at 23 ° c . in 50 % relative humidity . afterwards , testing of the foam properties was conducted . various foam properties were tested and are shown in table 2 . two 100 ml jars were filled each with 38 . 4 g of 1 - chloro - 3 , 3 , 3 - trifluoro - 1 - propene and 3 g of either polycat ™ 5 ( pentamethylated diethylenetriamine ; air products ) or mebpea respectively . both jars were sealed and hand shaken for 30 sec . almost immediately , the polycat ™ 5 solution generated a cloudy white precipitate , reflecting incompatibility of the polycat ™ 5 amine catalyst with the hydrochlorofluorocarbon in mixture . the mebpea remained clear for the initial 2 . 5 h . after standing overnight at room temperature , the polycat ™ 5 solution had become more colored in nature , with a dark ring formed around the surface of the jar / solution interface , whereas the mebpea had only a white cloudiness to its appearance , reflecting compatibility of the mebpea catalyst with the hydrochlorofluorocarbon in mixture .