CN104910010A - Method for producing di-trimethylolpropane heptylate - Google Patents

Abstract

The invention relates to a method for producing di-trimethylolpropane heptylate. The method is characterized by comprising the following steps: based on the purchased current batch of di-trimethylolpropane and heptylic acid, determining the theoretical molar ratio for complete esterification reaction with heptylic acid according to the number of hydroxyls in the adopted di-trimethylolpropane molecule, or selecting the small experiment molar ratio corresponding to current small experiment according to the previous experience molar ratio formed by the raw materials, and adjusting the small experiment molar ratio once or repeatedly so that the acid value of the current small experiment sample is less than or equal to 1.5mg KOH/g; performing decoloration and suction filtration, and detecting the separability between the synthetic liquid and water; and performing large-scale production by adopting the small experiment molar ratio at which the acid value of the current small exerpiemnt is less than or equal to 1.5mg KOH/g and the separability between the synthetic liquid and water meets the requirements as the molar ratio of the current batch of raw materials so as to realize economic and reasonable production of di-trimethylolpropane heptylate.

Description

A kind of method of producing ditrimethylolpropane heptanoate

Technical field

The invention belongs to organic chemistry raw material and manufacture field, relate to a kind of method of producing ditrimethylolpropane heptanoate.

Background technology

In numerous fatty acid esters, a class fatty acid ester is had to have the special construction of quaternary carbon atom, also known as neopentyl structure, typical example as: pentaerythritol fatty ester, bis pentaervthritol ester, trimethylolpropane fatty acid ester, ditrimethylolpropane fatty acid ester, neopentyl glycol fatty acid ester, they enjoy the favor of people.Because the β position carbon atom of the carbonyl of these neo-pentyl fatty acid esters does not have hydrogen atom, so can not with the resonance structure of the carbon of the alcohol moiety of ester group and hydrogen evolution six atom cycloalkyl, only have high-energy could destroy such ester structure, this makes the stability of the oxidation-resistance of amyl-based polyol fatty acid ester and anti-elimination reaction fine.Thus amyl-based polyol fatty acid ester has the unrivaled superiority of other ester class, becomes the optimal selection of the high-end synthetic ester in current lubricating oil.

Not only thermal oxidation stability is good for amyl-based polyol fatty acid ester, heat decomposition temperature is high, and resistance to low temperature good, easily degrade in the environment, the lubricant in the synthetic base oil of lubricating oil and metal rolled process can be used as, so be more and more subject to people's attention.

Although people have synthesized numerous amyl-based polyol fatty acid esters, but carrying out esterification with ditrimethylolpropane (also known as two-TriMethylolPropane(TMP), Di-trimethylolpropane) and enanthic acid under the effect of an acidic catalyst, to carry out the report of synthesizing bis (trihydroxy methyl propane) heptanoate little.

Ditrimethylolpropane is a kind of compound having four alcoholic extract hydroxyl groups, have neopentyl structure.It is unlike tetramethylolmethane, and its alcoholic extract hydroxyl group is not connected on a carbon atom, forms the molecule of stereo structure, but is dispersed on two carbon atoms, thus can form the molecule of flush type after being unlikely to carry out esterification with acid.Because the molecular weight of ditrimethylolpropane is larger, so although there is higher viscosity with the amyl-based polyol fatty acid ester that ditrimethylolpropane synthesizes, but the steric effect in molecule is not clearly, and viscosity index is higher, one of can yet be regarded as well lubricant, can be applied to the occasion needing high viscosity lubricants.

Although enanthic acid is somewhat expensive, but it is as a kind of saturated fatty acid with odd numbers of carbon atoms number, synthesize with it and amyl-based polyol, high fatty alcohol etc. the synthetic ester obtained, obvious feature is exactly that the pour point of product is low, can use at low ambient temperatures.

The technique document of current synthesis amyl-based polyol fatty acid ester series products is many, nothing more than employing direct esterification and ester-interchange method.Ester-interchange method owing to using basic catalyst, and can produce lower aliphatic alcohols etc. and has inflammable and byproduct that is explosion hazard, so in fact use seldom.Even employing direct esterification, be mostly adopt the excessive reaction forward of impelling of certain raw material to carry out, this will run into excessive raw material and the difficulty of product separation in follow-up purification, treating process.Even if adopt the means such as molecule rectifying to remove certain excessive raw material, even if can take off very thorough, also will inevitably cause the decline of target product yield, and the energy consumption that sepn process brings thus also can not be ignored, be thus difficult to synthesize the competitive product of price.

The current production technique display of some document reflection, in the process of synthesis amyl-based polyol fatty acid ester, adopts solvent or water entrainer to improve the efficiency of dehydration, makes esterification be unlikely to just can carry out at relatively high temperatures thoroughly.But one that adopts such technique to bring fearful effect finally will allow these solvents or water entrainer and product realize being separated thoroughly also very difficult.And the existence of a small amount of low boiling point solvent or water entrainer can cause the flash-point of product obviously to decline, at high temperature use to product and bring hidden danger.

The also current production technique display of some document reflection, in order to improve esterification yield, reduce the time of reaction, often adopts the excessive way of lipid acid to react, then carries out aftertreatment to product.To in the aftertreatment of product, mostly adopt neutralization, washing and point equal purification means.The consequence adopting such technology to bring is that the raw material of these acidity has loss, unit consumption is difficult to reach desirable level, production cost remains high.The salt produced in N-process is difficult to removing, and the process that will meet environmental requirement to the salt be in waste water is also a thing that make repeated headache.Because used alkaline matter in the process of aftertreatment, there is the situation of saponification reaction in the ester that also may occur to be synthesized, product is gone wrong again in follow-up use procedure.

Double the disclosed process data about synthetic ester, can find in current Technology in the selection of catalyzer, mostly the catalyzer of abandoning tradition, use load miscellaneous or composite catalyst instead.The cost in fact preparing various novel catalyzer is just higher, and the catalytic effect of these novel catalyzer is good not as good as traditional catalyst.Even if some solid catalyst can reclaim, but along with the effective constituent of in use solid-carried catalyst is constantly by wash-out, in fact these catalyzer can reusable restricted lifetime.

Because the source of raw material is different, production technique is also not quite similar, the index such as purity, foreign matter content of different batches raw material also exists trickle fluctuation, so qualified amyl-based polyol fatty acid ester will be produced, also need the feature for different batches raw material to carry out lab scale to grope, the proportioning of Reasonable adjustment raw material.

For the quality fluctuation of raw material between the deficiency of existing production amyl-based polyol fatty acid ester Product Process and different batches, be necessary the harmony considered production control cost and take into account quality product, adopt the tosic acid be easy to get as catalyzer, in conjunction with determining rational proportioning between different batches raw material by lab scale, come economical, reasonably produce ditrimethylolpropane heptanoate.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of method of producing ditrimethylolpropane heptanoate, employing tosic acid is catalyzer, in conjunction with adjusting, determine rational proportioning between different batches raw material by lab scale, economical, reasonably produce ditrimethylolpropane heptanoate.

For solving the problems of the technologies described above, technical scheme of the present invention is: for ditrimethylolpropane and the enanthic acid of purchasing the present lot come,

First determine the theoretical molar proportioning of carrying out with enanthic acid completely needed for esterification according to the quantity of hydroxyl in ditrimethylolpropane molecule used, or select the mol ratio of current lab scale according to the former experience mol ratio formed for ditrimethylolpropane and enanthic acid;

Adopt tosic acid as catalyzer, rely on heating to carry out esterification when logical nitrogen, and the water taken out of with nitrogen is collected by collection device, observe in collection device and no longer included after water deviates from 5 ~ 20 minutes, sampling, the acid number of working sample, makes current lab scale sample meet acid number≤1.5mgKOH/g by the adjustment of one or many lab scale mol ratio;

Add gac, continue heated and stirred 0.5 ~ 2h, then heating is stopped, when being cooled to 50 ~ 70 DEG C in lab scale sample, suction filtration is carried out while hot in the Büchner funnel being covered with diatomite and middling speed quantitative paper, product in filter flask is transferred in reagent bottle, the method specified according to GB/T 7305-2003, measure the separation property of synthesis liquid and water; After if the result display high-speed stirring recorded terminates within three ten minutes left standstill after, the volume of emulsion layer is less than 3mL, then represent that the separation property of this synthesis liquid and water is good, terminate this lab scale;

Acid number≤1.5mgKOH/g in this lab scale and synthesis liquid and water separation property also satisfactory lab scale mol ratio carry out large-scale production as the proportioning raw materials of present lot raw material.

Further, described concrete steps are as follows:

step S1: for ditrimethylolpropane and the enanthic acid of purchasing the present lot come, the quantity calculating hydroxyl in ditrimethylolpropane molecule used determines the theoretical molar proportioning of carrying out with enanthic acid completely needed for esterification, or selects the mol ratio of current lab scale according to the former experience mol ratio formed for ditrimethylolpropane and enanthic acid;

step S2:the mol ratio setting ditrimethylolpropane and enanthic acid in this lab scale is 0.9:4 ~ 1.2:4;

step S3:carry out lab scale, in the three-necked bottle of 500mL, first put into magnetic stir bar, drop into the enanthic acid of 0.8 ~ 2.0mol, then the ditrimethylolpropane meeting the respective batch that mol ratio requires in step S2 is dropped into, open the intensification switch of oil bath heater, material in still is heated, when temperature in the kettle is raised to 110 ± 4 DEG C, add enanthic acid and ditrimethylolpropane always feed intake quality 0.5 ~ 2% tosic acid as catalyzer, under nitrogen tube is inserted into liquid level, nitrogen is passed into the flow velocity of 10 ~ 100mL/min, open the stirring of stirrer in magnetic agitation still, timing from now, material in still is warmed up to 140 ~ 200 DEG C, heating 5 ~ 15h, the water of observing response by-product is deviate to the speed conditions in collection device under the drive of nitrogen, by the time no longer included after a water deviates from collection device in 5 ~ 20 minutes, sampling,

step S4:the acid number of working sample, if the acid number≤1.5mgKOH/g of sample, then leaps to step S9; If the acid number > 1.5mgKOH/g of sample, then enter next step;

step S5:continue reaction 0.5 ~ 2h;

step S6:the reacted acid number of sampling and measuring, if acid number≤1.5mgKOH/g, then jumps to step S9; If acid number > is 1.5mgKOH/g, then enter next step;

step S7:judge the absolute value of acid number and the adjacent last hypo acid value difference measured in above-mentioned steps S6, if this absolute value > is 0.5mgKOH/g, then return step S5; If this absolute value≤0.5mgKOH/g, then enter next step;

step S8:if acid number is > 1.5mgKOH/g still, then terminate this lab scale, and return step S2 and again adjust in the scope of 0.9:4 ~ 1.2:4 and the concrete mol ratio setting once enanthic acid and ditrimethylolpropane in lab scale test; If acid number≤1.5mgKOH/g, then enter next step;

step S9:add in three-necked bottle ditrimethylolpropane and enanthic acid always feed intake quality 0.5 ~ 2% gac, continue heated and stirred 0.5 ~ 2h, then heating is stopped, when being cooled to 50 ~ 70 DEG C in lab scale sample, in the Büchner funnel being covered with diatomite and middling speed quantitative paper, carry out suction filtration while hot, the product in filter flask is transferred in reagent bottle;

step S10:according to the method that GB/T 7305-2003 specifies, synthesis liquid in mensuration reagent bottle and the separation property of water, if be less than 3mL at the volume of the three ten minutes internal emulsification layers left standstill after the result display high-speed stirring recorded terminates, then represent that the separation property of this synthesis liquid and water is good, terminate this lab scale, write down this batch of ditrimethylolpropane and the suitable mol ratio of enanthic acid, using the mol ratio of this lab scale as proportioning raw materials when carrying out large-scale production with the raw material of present lot; If the separation property of measurement result display synthesis liquid and water is bad, then return step S2, finely tune the concrete mol ratio of enanthic acid and ditrimethylolpropane in lab scale test next time, then carry out lab scale next time;

step S11:large-scale production;

Further, the step of described large-scale production is specially:

step S111:the ditrimethylolpropane for present lot obtained with lab scale and the suitable mol ratio of enanthic acid, at 2M ³reactor in, drop into enanthic acid and ditrimethylolpropane, the total mass of raw material in still is made to be in the scope of 500 ~ 1500kg, open and stir, during beginning, rotating speed maintains 5 ~ 50rpm, open the heating valve of reactor, material in still is heated, when temperature in the kettle is raised to 115 ± 5 DEG C, add enanthic acid and ditrimethylolpropane always feed intake quality 0.5 ~ 2% tosic acid as catalyzer, open nitrogen valve, nitrogen is passed into the flow velocity of 1 ~ 100L/min, the rotating speed of stirring is brought up to 50 ~ 300rpm, timing from now, material in still is warmed up to 140 ~ 200 DEG C, heating 5 ~ 15h, the water of observing response by-product is deviate to the speed conditions in collection device under the drive of nitrogen, by the time no longer included after a water deviates from collection device in 5 ~ 20 minutes, sampling, the acid number of working sample,

step S112:if the acid number of sample can not reach≤level of 1.5mgKOH/g, then carry out reaction 0.5 ~ 2h, resampling detects acid number, until the acid number≤1.5mgKOH/g of sample;

step S113:add in reactor ditrimethylolpropane and enanthic acid always feed intake quality 0.1 ~ 2% gac, the diatomite of 0.1 ~ 1%, continue heated and stirred 0.5 ~ 3h, then heating is stopped, when being cooled to 50 ~ 70 DEG C Deng the temperature of product in still, open the valve at the bottom of still, with refining filtering pump by flow out material pumping in pressure filter, carry out circulation press filtration, press filtration material out turns back in reactor, till the color that circulation press filtration proceeds to the product returned has not seen that the activated carbon granule of diatomite particle and black is residual, product after press filtration being decoloured pours in pail pack.

The invention has the advantages that:

(1) each batch of raw material owing to buying has trickle fluctuation in purity, so adopt in the theoretical molar proportioning of corresponding raw material or the basis of experience mol ratio, the raw material of each batch is first adjusted to their proportioning by lab scale, until the acid number of amyl-based polyol fatty acid ester that lab scale is synthesized both met the requirements, also after meeting the requirements with the separation property of water, the feed molar proportioning adopting this suitable again goes to carry out large-scale production, raw material can be made to be fully utilized, ensure the quality of product, eliminate the highly energy-consuming that molecule rectifying is such, the lossy post-processing step of product, make production process economy, rationally, product has the market competitiveness.

(2) need not as current some processes, high, the not poisonous organic solvent of the boiling point such as toluene, dimethylbenzene is adopted to go as water entrainer, avoid the Dangerous and Harmful Factors in operating process, there is not the residual of low-boiling-point substance in product, thus ensure that the amyl-based polyol fatty acid ester be synthesized can at high temperature use.

(3) lipid acid owing to not adopting some traditional technologys to adopt is excessive, and then the technique that neutralizes is carried out with alkaline solution, eliminate washing and point equal post-processing step, and reluctant salts substances can not be produced, make that production process seems succinctly, environmental protection, avoid the product that is synthesized in the basic conditions again by the risk of saponification, hydrolysis.

(4) adopt traditional tosic acid as catalyzer, conveniently be easy to get, not exist batch between the discrepant problem of catalytic activity, it also has a benefit, be exactly that its fusing point is about 106 DEG C, after reaction end product cools down, in the process of decolorization filtering, the tosic acid of separating out from system can be filtered out together, realize being separated of catalyzer and product.

(5) gac and diatomite is adopted to combine as adsorption decolouriser, can the rational thickness of filter bed of heap, under the prerequisite of quality of guaranteeing to decolour, reduce the consumption of price greater activity charcoal, effectively reduce the cost of decolorization.

Embodiment

embodiment 1

step S1: for ditrimethylolpropane and the enanthic acid of purchasing the present lot come, have 4 hydroxyls in a ditrimethylolpropane molecule, then enanthic acid is 4 with the theoretical molar ratio of ditrimethylolpropane;

step S2:synthesize according to front the experience drawn several times, ditrimethylolpropane and the proper mol ratio of enanthic acid are 1.05:4 ;

step S3:carry out lab scale, in the three-necked bottle of 500mL, first put into magnetic stir bar, drop into 1.2mol(156.216g) enanthic acid, then correspondingly drop into 0.315mol(78.854g) ditrimethylolpropane, open the intensification switch of oil bath heater, material in still is heated, when temperature in the kettle is raised to 110 DEG C, add enanthic acid and ditrimethylolpropane always to feed intake the 1%(2.35g of quality 235.07g) tosic acid as catalyzer, under nitrogen tube is inserted into liquid level, nitrogen is passed into the flow velocity of 30mL/min, open the stirring of stirrer in magnetic agitation still, timing from now, material in still is warmed up to 160 ± 5 DEG C, heating 6.5h, the water of observing response by-product is deviate to the speed conditions in collection device under the drive of nitrogen, by the time no longer included after a water deviates from collection device in 10 minutes, sampling, the acid number of working sample, for 0.8mgKOH/g,

step S4:because the acid number of sample reaches≤the level of 1.5mgKOH/g, therefore directly enter step S9;

step S9:in three-necked bottle, add ditrimethylolpropane and enanthic acid always to feed intake the 1%(2.35g of quality) gac, continue heated and stirred 1h, then heating is stopped, when being cooled to 60 DEG C in lab scale sample, in the Büchner funnel being covered with diatomite and middling speed quantitative paper, carry out suction filtration while hot, the product in filter flask is transferred in reagent bottle;

step S10: the separation property measuring synthesis liquid and water, the result recorded is that when leaving standstill 30 minutes after high-speed stirring terminates, between oil phase and aqueous phase, the volume of emulsion layer is 5mL, represents that the separation property of this synthesis liquid and water is bad;

Return the concrete mol ratio that step S2 finely tunes enanthic acid and ditrimethylolpropane in lab scale test next time; For this batch of ditrimethylolpropane buied and enanthic acid, its mol ratio is adjusted to 1.03:4;

Then step S3 is entered, again drop into 1.2mol(156.216g) enanthic acid, then correspondingly drop into 0.309mol(77.352g) ditrimethylolpropane, to the product sampling synthesized, recording its acid number is 1.1mgKOH/g, proceed the decolouring of step S9, filter, then the separation property of synthesis liquid and water is measured, the result recorded be high-speed stirring terminate rear leave standstill 20 minutes time, between oil phase and aqueous phase, the volume of emulsion layer is 2mL, represent that the separation property of this synthesis liquid and water can accept, write down the raw material for this batch buied, suitable ditrimethylolpropane and the mol ratio of enanthic acid are 1.03:4, using the proportioning raw materials of this lab scale as proportioning raw materials when carrying out large-scale production with the raw material of present lot,

step S11:large-scale production.

The concrete steps of large-scale production are:

step S111: at 2M ³reactor in, drop into 781.08kg enanthic acid and 386.76kg ditrimethylolpropane, the total mass of raw material in still is made to reach 1167.84kg, open and stir, during beginning, rotating speed maintains 15rpm, open the heating valve of reactor, material in still is heated, when temperature in the kettle is raised to 115 DEG C, add enanthic acid and ditrimethylolpropane always to feed intake the 0.8%(9.34kg of quality) tosic acid as catalyzer, open nitrogen valve, nitrogen is passed into the flow velocity of 20L/min, the rotating speed of stirring is brought up to 150rpm, timing from now, material in still is warmed up to 160 ± 5 DEG C, heating 7h, the water of observing response by-product is deviate to the speed conditions in collection device under the drive of nitrogen, by the time no longer included after a water deviates from collection device in 10 minutes, sampling, the acid number of working sample, for 1.2mgKOH/g,

step S112:because the acid number of sample reaches≤the level of 1.5mgKOH/g, so reaction need not be proceeded again;

step S113:in reactor, add ditrimethylolpropane and enanthic acid always to feed intake the 0.3%(3.5kg of quality) gac, diatomite 0.15%(1.75kg), continue heated and stirred 1.5h, then heating is stopped, when being cooled to 60 DEG C Deng the temperature of product in still, open the valve at the bottom of still, with refining filtering pump by flow out material pumping in pressure filter, carry out circulation press filtration, press filtration material out turns back in reactor, after circulation press filtration carries out four minutes, the color of the product returned has not seen that the activated carbon granule of diatomite particle and black remains, product after press filtration being decoloured pours in pail pack.

Getting the sample of the ditrimethylolpropane heptanoate product that above-described embodiment obtains, be placed in reagent bottle, observe under natural light, is lurid thick liquid.Detect above-mentioned sample, recording its kinematic viscosity 40 DEG C time is 40.12mm ²/ s, kinematic viscosity when 100 DEG C is 7.58mm ²/ s, viscosity index is 160, its pour point <-35 DEG C, and flash-point is 260 DEG C.These data declaration ditrimethylolpropane heptanoates are a kind of well lubricants.

Claims (3)

1. produce a method for ditrimethylolpropane heptanoate, it is characterized in that: described method is ditrimethylolpropane and enanthic acid for purchasing the present lot come,

First determine the theoretical molar proportioning of carrying out with enanthic acid completely needed for esterification according to the quantity of hydroxyl in ditrimethylolpropane molecule used, or select the mol ratio of current lab scale according to the former experience mol ratio formed for ditrimethylolpropane and enanthic acid;

Adopt tosic acid as catalyzer, rely on heating to carry out esterification when logical nitrogen, and the water taken out of with nitrogen is collected by collection device, observe in collection device and no longer included after water deviates from 5 ~ 20 minutes, sampling, the acid number of working sample, makes current lab scale sample meet acid number≤1.5mgKOH/g by the adjustment of one or many lab scale mol ratio;

Add gac, continue heated and stirred 0.5 ~ 2h, then heating is stopped, when being cooled to 50 ~ 70 DEG C in lab scale sample, suction filtration is carried out while hot in the Büchner funnel being covered with diatomite and middling speed quantitative paper, product in filter flask is transferred in reagent bottle, the method specified according to GB/T 7305-2003, measure the separation property of synthesis liquid and water; After if the result display high-speed stirring recorded terminates within three ten minutes left standstill after, the volume of emulsion layer is less than 3mL, then represent that the separation property of this synthesis liquid and water is good, terminate this lab scale;

Acid number≤1.5mgKOH/g in this lab scale and synthesis liquid and water separation property also satisfactory lab scale mol ratio carry out large-scale production as the proportioning raw materials of present lot raw material.

2. the method for production ditrimethylolpropane heptanoate according to claim 1, is characterized in that described concrete steps are as follows:

step S1: for ditrimethylolpropane and the enanthic acid of purchasing the present lot come, the quantity calculating hydroxyl in ditrimethylolpropane molecule used determines the theoretical molar proportioning of carrying out with enanthic acid completely needed for esterification, or selects the mol ratio of current lab scale according to the former experience mol ratio formed for ditrimethylolpropane and enanthic acid;

step S2:the mol ratio setting ditrimethylolpropane and enanthic acid in this lab scale is 0.9:4 ~ 1.2:4;

step S3:carry out lab scale, in the three-necked bottle of 500mL, first put into magnetic stir bar, drop into the enanthic acid of 0.8 ~ 2.0mol, then the ditrimethylolpropane meeting the respective batch that mol ratio requires in step S2 is dropped into, open the intensification switch of oil bath heater, material in still is heated, when temperature in the kettle is raised to 110 ± 4 DEG C, add enanthic acid and ditrimethylolpropane always feed intake quality 0.5 ~ 2% tosic acid as catalyzer, under nitrogen tube is inserted into liquid level, nitrogen is passed into the flow velocity of 10 ~ 100mL/min, open the stirring of stirrer in magnetic agitation still, timing from now, material in still is warmed up to 140 ~ 200 DEG C, heating 5 ~ 15h, the water of observing response by-product is deviate to the speed conditions in collection device under the drive of nitrogen, by the time no longer included after a water deviates from collection device in 5 ~ 20 minutes, sampling,

step S4:the acid number of working sample, if the acid number≤1.5mgKOH/g of sample, then leaps to step S9; If the acid number > 1.5mgKOH/g of sample, then enter next step;

step S5:continue reaction 0.5 ~ 2h;

step S6:the reacted acid number of sampling and measuring, if acid number≤1.5mgKOH/g, then jumps to step S9; If acid number > is 1.5mgKOH/g, then enter next step;

step S7:judge the absolute value of acid number and the adjacent last hypo acid value difference measured in above-mentioned steps S6, if this absolute value > is 0.5mgKOH/g, then return step S5; If this absolute value≤0.5mgKOH/g, then enter next step;

step S8:if acid number is > 1.5mgKOH/g still, then terminate this lab scale, and return step S2 and again adjust in the scope of 0.9:4 ~ 1.2:4 and the concrete mol ratio setting once enanthic acid and ditrimethylolpropane in lab scale test; If acid number≤1.5mgKOH/g, then enter next step;

step S9:add in three-necked bottle ditrimethylolpropane and enanthic acid always feed intake quality 0.5 ~ 2% gac, continue heated and stirred 0.5 ~ 2h, then heating is stopped, when being cooled to 50 ~ 70 DEG C in lab scale sample, in the Büchner funnel being covered with diatomite and middling speed quantitative paper, carry out suction filtration while hot, the product in filter flask is transferred in reagent bottle;

step S10:according to the method that GB/T 7305-2003 specifies, synthesis liquid in mensuration reagent bottle and the separation property of water, if be less than 3mL at the volume of the three ten minutes internal emulsification layers left standstill after the result display high-speed stirring recorded terminates, then represent that the separation property of this synthesis liquid and water is good, terminate this lab scale, write down this batch of ditrimethylolpropane and the suitable mol ratio of enanthic acid, using the mol ratio of this lab scale as proportioning raw materials when carrying out large-scale production with the raw material of present lot; If the separation property of measurement result display synthesis liquid and water is bad, then return step S2, finely tune the concrete mol ratio of enanthic acid and ditrimethylolpropane in lab scale test next time, then carry out lab scale next time;

step S11:large-scale production.

3. the method for production ditrimethylolpropane heptanoate according to claim 1 and 2, is characterized in that the step of described large-scale production is specially:

step S111:the ditrimethylolpropane for present lot obtained with lab scale and the suitable mol ratio of enanthic acid, at 2M ³reactor in, drop into enanthic acid and ditrimethylolpropane, the total mass of raw material in still is made to be in the scope of 500 ~ 1500kg, open and stir, during beginning, rotating speed maintains 5 ~ 50rpm, open the heating valve of reactor, material in still is heated, when temperature in the kettle is raised to 115 ± 5 DEG C, add enanthic acid and ditrimethylolpropane always feed intake quality 0.5 ~ 2% tosic acid as catalyzer, open nitrogen valve, nitrogen is passed into the flow velocity of 1 ~ 100L/min, the rotating speed of stirring is brought up to 50 ~ 300rpm, timing from now, material in still is warmed up to 140 ~ 200 DEG C, heating 5 ~ 15h, the water of observing response by-product is deviate to the speed conditions in collection device under the drive of nitrogen, by the time no longer included after a water deviates from collection device in 5 ~ 20 minutes, sampling, the acid number of working sample,

step S112:if the acid number of sample can not reach≤level of 1.5mgKOH/g, then carry out reaction 0.5 ~ 2h, resampling detects acid number, until the acid number≤1.5mgKOH/g of sample;

step S113:add in reactor ditrimethylolpropane and enanthic acid always feed intake quality 0.1 ~ 2% gac, the diatomite of 0.1 ~ 1%, continue heated and stirred 0.5 ~ 3h, then heating is stopped, when being cooled to 50 ~ 70 DEG C Deng the temperature of product in still, open the valve at the bottom of still, with refining filtering pump by flow out material pumping in pressure filter, carry out circulation press filtration, press filtration material out turns back in reactor, till the color that circulation press filtration proceeds to the product returned has not seen that the activated carbon granule of diatomite particle and black is residual, product after press filtration being decoloured pours in pail pack.