the present invention provides a new use for certain amino alcohol compounds , which are derivatives of 4 - hydroxyacetophenone , a well - known basic building block for numerous organic compounds . these novel amino alcohols have the general formula : ## str3 ## wherein : n is 1 to 1000 ( preferably 1 - 100 ); r 1 = r 2 , and r 1 and r 2 are from the group : -- ch 2 -- ch 2 --, -- ch 2 -- c ( ch 3 ) h --, and -- c ( ch 3 ) h -- ch 2 -- r 3 and r 4 are each independently selected from the group : -- h , -- ch 3 , -- ch 2 ch 3 , -- ch 2 oh , and -- ch 2 -- ch 2 -- oh ; and the compounds are useful as algistats . in particular , the compounds are useful as additives in paints , particularly water - based paints , coatings , polymers , paper manufacturing , swimming pools , decorative ponds and fountains , evaporative coolers ( cooling towers ), cleaning solutions , and the like water - containing materials . solutions containing the compound may be used to treat surfaces as for example showers , bath compartments , saunas , steam rooms , and similar areas which are moisture . in certain areas of the world where the average humidity is high , a solution of the compounds may be used to treat roofs , walls , cloth used for clothing , tents , dining flies , ground cloths , and the like . the compound useful for the present invention is prepared by reacting an alkali metal salt of 4 - hydroxyacetophenone with an organic oxide , such as ethylene oxide or propylene oxide , in the presence of a suitable catalyst ; then subjecting the reaction product to reductive amination under pressure to form the compound . processes for the manufacture of the compound useful for the present invention are disclosed and claimed in u . s . pat . no . 5 , 300 . 691 . useful concentrations of the compound , when used to control the growth of algae in liquid applications , can be from about 1 to about 100 mg / l ., preferably from about 2 . 5 to about 10 mg / l . for use , the compound is preferably dissolved in a minimum amount of a solvent therefore and then disbursed in the water at the desired concentration . solvents may include alcohols , ketones , esters , ethers , and the like . when a compound is used to control the growth of algae on surfaces is can be applied to the surface as a solution in an appropriate solvent or from a slurry in any non - interferring liquid . test compound : compound ( 1 ) wherein n = 30 , r 1 = r 2 =-- ch 2 -- ch ( ch 3 )--, and r 3 = r 4 = h test species : freshwater green alga ( selenastrum capricomutum ); 4 - day old culture at test initiation dilution medium : freshwater algal growth medium with an initial ph of 7 . 5 + 0 . 1 ; test temperature ranged from 23 . 0 to 25 . 6 ° c . nominal concentrations : control , 0 . 63 , 1 . 25 , 2 . 50 , 5 . 00 , and 10 . 0 mg whole material ( wm )/ l results : the 96 - hour ec50 to s . capricornutum was 1 . 38 mg wm / l ( based on nominal concentrations ). the 96 - hour noec was 0 . 63 mg wm / l based on the lack of significant inhibitory effects observed at this test concentration . the test substance was a golden brown viscous liquid and purity was & gt ; 98 %. the test substance was stored in the dark at ambient room temperature . nominal test concentrations are reported as milligrams ( mg ) of compound as whole material ( wm ) per liter ( l ) of freshwater algal medium . the freshwater alga tested was the green alga , selenastrum capricornutum ( utex # 3648 ). the culture originated from an inoculum received from the university of texas at austin and maintained since oct . 4 , 1989 . the algae were cultured on freshwater algal medium under continuous illumination yielding approximately 50 micromols per square meter per second ( pmols / m 2 / s ). cultures were maintained at approximately 24 + 2 ° c . prior to test initiation and were checked for purity weekly . the inoculum culture was 4 days old at test initiation . the base water for the test medium was deionized water . the base water was sterilized and enhanced with reagent - grade nutrients . the ph of the test medium was adjusted to a ph of 7 . 5 with 0 . 1 n naoh or hcl prior to use in the test . the test medium was filtered through a 0 . 45μ membrane filter prior to use . two static range - finding tests were conducted prior to performing the definitive test . both tests were conducted at nominal test concentrations of 0 . 10 , 1 . 00 , 10 . 0 , 100 , and 1000 mg wm / l . the first test was aborted due to irregular algal growth among the controls and treatments . for the second range - finding test , inhibition of cell growth ( based on cell number ) compared to the pooled controls ranged from 23 percent at 1 . 00 mg wm / l to 99 percent at 1000 mg wm / l after 96 hours of exposure . there was a stimulation effect to algal growth ( 5 %) at 0 . 10 mg wm / l . undissolved chemical was observed at 100 and 1000 mg wm / l . based upon these results , nominal test concentrations of 0 . 63 , 1 . 25 , 2 . 50 , 5 . 00 , and 10 . 0 mg wm / l were selected for the definitive test . the definitive exposure was conducted under static conditions in an environmentally controlled chamber set to provide a test temperature of 24 + 2 ° c . a primary stock solution ( 100 . 040 mg wm / l ) was prepared by weighing 1 . 0004 g of the test compound into a 10 - ml volumetric flask and then bringing to volume with acetone . four additional stocks ( 50 , 020 ; 25 , 010 ; 12 , 505 ; and 6 , 253 mg wm / l ) were prepared by serial dilution starting with the primary stock . each serially diluted stock solution was prepared by pipeting 5 ml of the appropriate stock solution into a 10 ml volumetric flask and bringing to volume with acetone . test solutions ( i . e ., 10 . 0 , 5 . 00 , 2 . 50 , 1 . 25 , and 0 . 63 mg wm / l ) were prepared by adding 40 μl of the appropriate stock solution to 400 - ml volumes of filtered test medium . an algal test medium control and a solvent ( acetone ) control were maintained concurrently with the test solutions . the acetone concentration in the solvent control and all test solutions was 0 . 1 ml / l . following stirring , ph measurements were taken and then four 100 ml aliquots of each test solution were transferred to sterilized 250 - ml glass erlenmeyer flasks ( including one chemical blank ). three replicates were inoculated with algae while the fourth was established as a chemical &# 34 ; blank &# 34 ; control for each treatment and was not inoculated with algae . all flasks were capped with gas exchange caps . the 96 - hour exposure was initiated with the inoculation of approximately 10 , 000 cells / ml to each test flask ( 234 μl of an inoculum culture with a cell density of 428 × 104 cells / ml ). the test chambers were randomly positioned in a temperature - controlled chamber under continuous fluorescent lighting and continuously swirled on an orbital shaker table at approximately 100 rpm ( revolutions per minute ). test chambers were impartially re - positioned daily to eliminate position effects . light intensity ranged between 35 . 3 and 63 . 3 ( mols / m 2 / s as measured by a li - cor , inc . model li - 189 light meter equipped with a 2π quantum sensor . algal growth was measured at least three times per inoculated flask by direct cell counts using an electronic particle counter ( coulter counter model z1 ) every 24 hours . morphological observations were also conducted on each test treatment daily using a compound microscope to detect abnormal cell morphology and coloration as compared to the control . chemical &# 34 ; blanks &# 34 ; were counted concurrently with each test concentration to establish a background level , if any was present . to eliminate any effect of background during counting , the mean of the treatment blank was subtracted from the appropriate cell counts of the coinciding replicates prior to statistical analysis for all treatments and controls . all cell numbers presented in this report have already been corrected for any background detected . after 96 hours , algal growth was maximally inhibited at nominal concentrations of 5 . 00 and 10 . 0 mg wm / l ( i . e ., either no algal growth or a net decrease in algal growth as compared to the initial inoculum ); therefore , evaluation for algistatic versus algicidal response was necessary . this was accomplished by removing 0 . 5 ml aliquots of test solution containing growth - inhibited algae from each replicate test chamber . these aliquots ( 1 . 5 mil total volume ) were combined for each maximally inhibited test concentration into new test flasks and diluted with fresh ( test substance free ) algal medium to 100 ml , resulting in a test concentration of & lt ; 0 . 15 mg wm / l ( a nominal test substance concentration which did not affect growth as compared to the control ). a control flask was also set up with an initial cell density of approximately 10 , 000 cells / ml to confirm acceptability of the procedures . the subcultures were incubated under the environmental conditions of the definitive test . the recovery phase was conducted for six days and was discontinued as soon as significant algal growth occurred in the maximally inhibited treatment . algal growth was measured during the recovery phase by direct cell counts using a hemocytometer counting chamber with a compound microscope . temperature was measured in one uninoculated flask of test medium daily during the test . the temperature range of the environmentally controlled chamber was monitored using a minimum / maximum thermometer and the diurnal temperature ranges recorded daily . light intensity was measured daily during the 96 - hour exposure period at the level of the test solutions . the ph was measured at test initiation in the composites and at test termination in all control and test flasks using a fisher accumet ® 1001 ph meter . no water samples were collected or analyzed during the tests . nominal concentrations were used during both the range - finding and definitive tests . algal growth response ( as percent inhibition , i , or stimulation , s , in the test solutions compared to the controls ) was calculated as follows : % i =--( c -- t )/ c × 100 or % s =( t -- c )/ c × 100 where c = mean growth of the control and t = mean growth of treated culture . mean and standard deviation of the algal responses were calculated and plotted for each treatment and control . based on results of the test ( percent inhibition of cell growth ), the 96 hour ec 10 , ec 50 , and ec 90 values with their 95 percent confidence limits were calculated . after 96 hours of exposure , the percent inhibitor in cell numbers compared to the pooled controls ranged from 12 percent at 0 . 63 mg wm / l to 99 + percent at 5 . 00 and 10 . 0 mg wm / l . daily mean cell counts and standard deviations for the control and test solutions are presented in table 1 . growth curves show that algae in the controls and low treatments exhibited a pattern of - exponential growth during the 96 - hour growth period . the coefficient of variation for cell numbers in the control was 4 %. observations of cell morphology detected no differences in treated algal cells as compared to the control cells . the 96 - hour ec 10 , ec 50 , and ec 90 values were calculated using the probit method to be 0 . sup .˜ 64 , 1 . 38 , and 2 . 97 mg wm / l , respectively . the noec was 0 . 63 mg wm / l , based on the lack of significant inhibitory effects observed at these test concentrations . no undissolved chemical was observed in the test medium during the test . the measured test temperature during the 96 - hour exposure ranged from 23 . 0 to 25 . 6 ° c . the initial ph of the controls and all test solutions ranged from 7 . 1 to 7 . 5 . all phs were adjusted to 7 . 5 + 0 . 1 before inoculation with the algae at test initiation . after 96 hours , the ph ranged from 7 . 0 to 7 . 3 in the test solutions and from 7 . 2 to 7 . 8 in the controls . in the recovery phase of the study , which was conducted to separate algistatic from algicidal effects of the test substance , significant growth of the algae was observed in all of the recovery treatments after 6 days of incubation . this demonstrated that the effect of the compound to the freshwater alga was algistatic in nature and not algicidal . the measured test - temperature during the 6 - day recovery period ranged from 25 . 0 to 27 . 0 ° c . light intensity ranged between 50 . 6 and 55 . 3 μmols / m2 / s . there were two deviations from the test protocol during the conduct of this study . 1 . the stock algal culture was 4 days old at test initiation instead of 5 - 10 days as stated in the protocol . the initiation of the test was based on the growth conditions of the stock algae ( pattern of exponential growth ). 2 . the test temperature during the recovery phase ranged from 25 . 0 to 27 . 0 ° c ., slightly exceeding the range stated in the protocol ( 24 + 2 ° c .). in the scientific opinion of the study director , these deviations did not affect the outcome or validity of the test results . table 1______________________________________cell numbers ( as determined by an electronic particle counter ) after 96 hours of continuous exposure of the green alga , selenastrum capricornutum under static test conditionsnominalconcentration mean cell numbers (× 104 , / ml ) percent ( mg wm / l ) 24 hr 48 hr 72 hr 96 hr change______________________________________control 1 . 18 6 . 66 42 . 3 244 -- ( 0 . 12 ) ( 0 . 30 ) ( 7 ˜ 25 ) ( 958 ) solvent 1 . 26 6 . 60 35 . 8 226 -- control ( 0 . 35 ) ( 2 . 14 ) ( 9 ˜ 33 ) ( 23 . 2 ) 0 . 63 1 . 37 6 . 40 38 . 3 208 - 12 ( 0 . 25 ) ( 1 ˜ 19 ) ( 3 . 74 ) ( 1 . 33 ) 1 . 25 1 . 15 4 . 54 23 . 9 142 - 40 ( 0 . 31 ) ( 2 . 97 ) ( 18 ≠ 1 ) ( 95 . 3 ) 2 . 50 0 . 81 2 . 01 8 . 55 43 . 3 - 82 ( 0 . 28 ) ( 0 . 43 ) ( 2 . 75 ) ( 15 . 6 ) 5 . 00 0 . 36 0 . 32 3 . 04 0 . 31 - 99 + ( 0 . 28 ) ( 0 . 27 ) ( 4 . 43 ) ( 0 . 52 ) 10 . 0 0 . 02 0 . 02 0 . 00 1 . 12 - 99 + ( 0 ˜ 06 ) ( 0 . 03 ) ( 0 . 39 ) ( 0 . 93 ) pooled 1 . 22 6 . 63 39 . 1 235 -- controls______________________________________ values are means and standard deviations of triplicate test chambers ; the standard deviations are presented in parentheses . percent inhibition as determined against pooled control cell numbers at 9 hours ( 235 × 104 cells / ml ). note : coefficient variation = standard deviation × 100 / mean
the present invention relates to a method for the prevention of growth of algae by incorporating within liquids or coating on surfaces certain substituted amino alcohols . more precisely , this invention provides for algistat end uses for amino alcohol compounds endowed with chain extension which have the general formula : ## str1 ## wherein n is 1 - 1000 ; and r 1 = r 2 , and r 1 and r 2 are from the croup consisting of -- ch 2 -- ch 2 --; -- ch 2 -- ch --; and -- ch -- ch 2 --; r 3 , and r 4 are each independently selected from the group consisting of h , -- ch 3 , -- ch 2 ch 3 , -- ch 2 oh , and -- ch 2 -- ch 2 -- oh ; and the diasteromeric salts thereof .